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Méthode RehabiMed Architecture Traditionnelle Méditerranéenne II. Réhabilitation Bâtiments Método RehabiMed Arquitectura Tradicional Mediterránea II. Rehabilitación El Edificio

RehabiMed Method Traditional Mediterranean Architecture

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Méthode RehabiMed Architecture Traditionnelle Méditerranéenne II. Réhabilitation Bâtiments Método RehabiMed Arquitectura Tradicional Mediterránea II. Rehabilitación El Edificio

RehabiMed Method Traditional Mediterranean Architecture

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9 THIS PROGRAMME IS FINANCED BY THE EUROPEAN UNION

EUROMED

EUROMED HERITAGE

AGENCIA ESPAÑOLA DE COOPERACIÓN INTERNACIONAL

COL·LEGI D’APARELLADORS I ARQUITECTES TÈCNICS DE BARCELONA

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Consortium RehabiMed: Project Manager: Xavier CASANOVAS Members: Ministry of Communications and Works Department of Antiquities of Cyprus Person in charge: Evi FIOURI Bureau Culturel de l'Ambassade de la République Arabe d'Egypte en France Supreme Council of Antiquities, Egypte Persons in charge: Mahmoud ISMAÏL and Wahid Mohamed EL-BARBARY Col·legi d’Aparelladors i Arquitectes Tècnics de Barcelona, Espagne Persons in charge: Xavier CASANOVAS Ecole d’Avignon, France Persons in charge: Gilles NOURISSIER Centre Méditerranéen de l'Environnement Marrakech, Maroc Persons in charge: Moulay Abdeslam SAMRAKANDI Institut National du Patrimoine, Tunisie Persons in charge: Mourad RAMMAH

Director: Xavier CASANOVAS Coordination of the volumes: Oriol CUSIDÓ Ramon GRAUS Amèlia MARZAL Development and drafting of the method: Oriol CUSIDÓ Ramon GRAUS

Network of experts of the RehabiMed Consortium: Cyprus Persons in charge: Evi FIOURI and Irene HADJISAVVA Constantinos ALKIDES Athina ARISTOTELOUS-CLERIDOU Michael COSMAS Eliana GEORGIOU Kyriakos KOUNDOUROS Yiola KOUROU Athina PAPADOPOULOU Agni PETRIDOU Eleni PETROPOULOU Maria PHILOKYPROU Eleni PISSARIDOU Socrates STRATIS Egypt Persons in charge: Mahmoud ISMAÏL and Wahid EL-BARBARY Mahmoud ABD EL MAGEED Mahmoud EL-ALFY Mohamed ELARABY Philippe HEARINGER Hany HELAL Bernard MAURY Mohamed SIEF AL-YAZEL Spain Persons in charge: Oriol CUSIDÓ and Ramon GRAUS Martí ABELLA Josep ARMENGOL Santiago CANOSA

Cèsar DÍAZ GÓMEZ Albert FUSTER José Luis GARCÍA GRINDA Soledad GARCÍA MORALES José Luis GONZÁLEZ MORENO-NAVARRO María-José JIMÉNEZ José Manuel LÓPEZ OSORIO Carmen MARZO Irene MARZO Camilla MILETO Joaquín MONTÓN Josep MUNTAÑOLA Francisco POL Emilio RAMIRO Pere ROCA Cristina THIÓ Fernando VEGAS Antoni VILANOVA Montserrat VILLAVERDE France Persons in charge: René GUERIN and Patrice MOROT-SIR Xavier BENOIST Christophe GRAZ Maria LÓPEZ DÍAZ Michel POLGE Jean-Alexandre SIRI Christian THIRIOT Véronique WOOD Morocco Persons in charge: Abderrahim KASSOU and Quentin WILBAUX Karim ACHAK Mohamed BOUAZZAOUI Hicham ECHEFAA Jamal-Eddine EL-GHORAFI Ameziane HASSSANI Oum-Kaltoum KOBBITE Said LOQMANE Abdellatif MAROU Ahmed OUARZAZI Tunisia Persons in charge: Radhia BEN M’BAREK and Abdellatif GHILENE Mourad RAMMAH Mohamed KERROU

Monther JAMHAWI (Jordanie) Oussama KALLAB (Lebanon) Nikolaos KALOGIROU (Greece) Vito LAUDADIO (Italy) Yasmine MAKAROUN BOU ASSAF (Lebanon) Moshe MAMON (Israel) Hilmi MARAQA (Palestine) Filipe MARIO LOPES (Portugal) Nikolaos MOUTSOPOULOS (Greece) Farhat MUHAWI (Palestine) Yael F. NA’AMAN (Israel) Yassine OUAGENI (Algeria) Alkmini PAKA (Greece) Rubi PELED (Israel) Avi PERETS (Israel) Simona PORCELLI (Italy) Bougnerira-Hadj QUENZA (Algeria) Cristina Scarpocchi (Italy) Sinan SENIL (Turkey) Haluk SEZGIN (Turkey) Mai SHAER (Jordan) Yaacov SHAFFER (Israel) Ram SHOEF (Israel) Giambattista DE TOMMASI (Italy) Shan TSAY (Jordan) Fandi WAKED (Jordan) Eyal ZIV (Israel) Scientific Committee of the Rehabimed Project: Brigitte COLIN (UNESCO) Josep GIRALT (IEMed) Paul OLIVER (Oxford Brookes University) English translation: Elaine FRADLEY ADDENDA Illustrations: Joan CUSIDÓ Cover illustration: Fernando VEGAS, Camilla MILETO Photographic material: RehabiMed, CORPUS and CORPUS Levant teams. Other sources are indicated with the photo. Graphic design: LM,DG : Lluís MESTRES

Collaborating experts in other Mediterranean countries:

Website: www.rehabimed.net

Nur AKIN (Turkey) Nazmi AL-JUBEH (Palestine) Mustafa AL-NADDAF (Jordan) Ziad AL-SAAD (Jordan) Suad AMIRY (Palestine) Koksal ANADOL (Turkey) Carlo ATZENI (Italy) Abdelaziz BADJADJA (Algeria) Kurtel BELMA (Turkey) Demet BINAN (Turkey) Can BINAN (Turkey) Andrea BRUNO (Italy) Khaldun BSHARA (Palestine) Yotam CARMEL (Israel) Banu ÇELEBIOGLU (Turkey) Vito CENTRONE (Italy) Nathalie CHAHINE (Lebanon) Ofer COHEN (Israel) Michel DAOUD (Lebanon) Habib DEBS (Lebanon) Michelangelo DRAGONE (Italy) Reuven ELBERGER (Israel) Tal EYAL (Israel) Fabio FATIGUSO (Italy) Antoine FISCHFISCH (Lebanon) Yael FUHRMANN-NAAMAN (Israel) Giovanni FURIO (Italy) Sinan GENIM (Turkey) Feyhan INKAYA (Turkey)

© 2007 Col·legi d’Aparelladors i Arquitectes Tècnics de Barcelona pour le consortium RehabiMed Bon Pastor, 5 – 08021 Barcelona, Espagne rehabimed@apabcn.cat ISBN : 84-87104-75-4 RehabiMed wish to encourage the reproduction of this work and the diffusion of its contents, with due mention of its source. This project is financed by the Euromed Heritage programme of the European Union and by the Agencia Española de Cooperación Internacional (AECI). The opinions expressed in this document do not necessarily reflect the position of the European Union or its member states.


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Preface The first Euromediterranean Conference of heads of state in 1995 saw the launch of the Barcelona process, an ambitious initiative ratified in 2005 at the Barcelona +10 Summit. The priority objectives are intended to seek sociopolitical, economic, cultural and environmental synergies from a regional and mutual development viewpoint. It was within this context that the Euromed Heritage Programme emerged in 1998, to contribute towards the improvement and protection of the diverse heritage shared by the different Mediterranean countries. Traditional architecture, as an essential part of the cultural legacy generated by the collective imagination of the Mediterranean, plays an important part in the actions carried out by Euromed Heritage. In their first years, CORPUS and CORPUS Levant carried out an enormous task cataloguing and analysing the characteristics and typologies of traditional Mediterranean architecture, identifying the problems presented and suggesting the best alternatives for preserving it. RehabiMed wanted to continue this stage of analytical study to develop the essential ideas arising from the needs and urgent requirements detected by these projects – promoting effective, respectful rehabilitation.

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Today, in a globalised world, where economic and cultural uniformity mark the development criteria to be followed based on standard patterns, RehabiMed's proposal is even more meaningful. Rehabilitation counteracts the idea of globalisation, and regional wealth, cultural diversity, different ways of life and particular local features become essential elements to be preserved.

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There are many public and private initiatives aimed at recovering constructed heritage; some are oriented towards singular, monumental heritage, which we call Restoration, and others, as is the case with RehabiMed, are directed towards more modest, more abundant heritage with a greater presence in the territory, such as traditional architecture in historic town centres, rural villages and dispersed throughout the territory. This is what we call Rehabilitation, always carried out to provide buildings – the majority of them without any kind of heritage protection – with a use. This activity involving action on what has been built presents a wide diversity of situations, if we look at the Mediterranean sphere. In European countries, rehabilitation activity represents almost 50% of total activity in the sector, while in the countries of the south and east of the Mediterranean basin, this activity does not amount even to 10% of activity in the sector, despite its importance concerning economic development and the social cohesion of the population.

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RehabiMed's aim is to reinforce rehabilitation activity and maintaining traditional Mediterranean architecture as a factor in sustainable (social, economic and environmental) development. Achieving this objective will allow us to move forward with two historical challenges that may appear contradictory but from our point of view are perfectly compatible and complementary: firstly, contributing towards improving the living conditions of residents, who are the people who give meaning and life to this heritage; and, secondly, contributing to preserving the historical and cultural identity of Mediterranean peoples. To achieve this aim, RehabiMed's approach has been to work in three directions. Firstly, we have developed some strategic and methodological tools orientated towards rehabilitation; alongside these, we have carried out various publicity actions and training for professionals in the spirit of the content of the tools developed; and, finally, we have launched four pilot operations with real rehabilitation work to test, experiment and demonstrate the importance, possibilities and positive effects represented by good rehabilitation policy.

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They have been three years of hard work, constructive debates and experiences shared with experts, with students and, above all, with the population directly linked to our actions, which has allowed us to meet the objective we initially set. We believe that the results are excellent and that we have created a good starting point for rehabilitation to get off on the right foot, giving meaning to the tools created, the training given and the experiments carried out. I am delighted to present the first volume of our methodological work, the result of the effort of more than 150 experts from different professional spheres in 15 countries. The texts in this publication contain the RehabiMed Method for rehabilitation of Traditional Mediterranean Architecture, which have been considered and drawn up at length to respond to the concerns of our collaborators and experts. In addition, the publication develops the different points put forward by the RehabiMed Method to provide guidelines on specific proposals, to facilitate their application and to show different situations sharing very similar forms of action in the rehabilitation of the regional and urban heritage of traditional architecture. All this should serve politicians and officers of the different administrations to make it easier for them to generate and develop their initiatives to promote rehabilitation from a very broad frame of reference, raising the awareness of the population and getting it to take an active part in decision-making.

Xavier Casanovas RehabiMed Project Manager Barcelona, 30 June 2007


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RehabiMed Method Traditional Mediterranean Architecture II. Rehabilitation. Buildings

Preface Introduction Traditional Mediterranean Architecture A changing world. Architecture under threat Rehabilitating Traditional Mediterranean Architecture The RehabiMed Method on the scale of the building. The Guide and its constituent tools

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Part 1. The RehabiMed Guide to the rehabilitation of traditional buildings. An integrated approach to the building I / Objectives of the Guide II / The initial agents in the process III / The phases of the Guide

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I. Knowledge 1. Preliminaries Decision to take action / Interview with the client Preliminary diagnosis The preliminary diagnosis report 2. Multidisciplinary studies (analysis) Establishing of provisional hypotheses Programme of multidisciplinary studies Social aspects Historical aspects Architectural aspects Construction aspects

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II. Reflection and the project 3. Diagnosis (synthesis) Critical evaluation of studies Confirmation of hypotheses Writing a report 4. Reflection and decision-making Feasibility Confirmation of criteria Decision-making 5. Project Outline proposals Project

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III. The work 6. Rehabilitation Tender action Obtaining the building permit Carrying out the work Handover of the work

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IV. Lifespan 7. Maintenance Publicizing the building’s values among the community Choice of the model of maintenance The ‘identity card’ Maintenance work according to a timeframe

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Part 2. The RehabiMed tools. An aid to the rehabilitation of traditional buildings I. Knowledge Tool 1. Knowledge of traditional architecture as a basis for rehabilitation Traditional Mediterranean Architecture. Territory, landscape and traditional architecture. José Luis García Grinda 49 Traditional Mediterranean Architectures: collective values. Michel Polge 67 The Social and Cultural Values of Cultural Heritage in Palestine: Whose values, the practitioners or the owners? Suad Amiry, Farhat Muhawi 72 Architectural heritage: adaptation, use and maintenance. Abdelaziz Badjadja 75 Bioclimatic values in the rehabilitation of Traditional Mediterranean Architecture. Xavier Casanovas, Ramon Graus 78 Traditional architecture and climate in Tunisia. Radhia Ben M’barek 87 A tool to develop the use of solar energy in Mediterranean basin: the European Solar Radiation Atlas (ESRA). École des Mines de Paris 90 Tool 2. Starting with a precise preliminary diagnosis Steps for an engineering (and non-structural) survey in pre-diagnosis phase. Yaacov Schaffer Support material for the preliminary diagnosis stage. Ramon Graus The preliminary diagnosis - the Cyprus experience. Yiola Kourou Tool 3. Overall knowledge of the building The programme of studies. Fernando Vegas, Camilla Mileto Historical studies and archaeological interventions: Tools for the knowledge of Traditional Mediterranean Architecture. Abdellatif Marou, Jordi Ortega, Montserrat Villaverde Archaeology as a tool for finding out about the building. Evi Fiouri Applying the archaeological method to Lebanese architecture. Yasmine Makaroun Bou Assaf A comprehensive understanding of the building. José Luis González Moreno-Navarro

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Architectural analysis of buildings. Typologies in Cyprus. Eliana Georgiou Thermal comfort in existing homes. Maria López Díaz Acoustic comfort in existing homes. Christian Thiriot Tool 4. Making the graphic survey of the building Preliminary reflections on the graphic survey of vernacular heritage. Santiago Canosa Reboredo Pointers for drawing up a good survey. Michel Daoud Graphic Survey. The Cypriot experience. Eleni Pissaridou Stratigraphic analysis of architecture and its application to traditional architecture. Camilla Mileto The colour study, the first step in rehabilitating a façade. Ramon Graus, Cristina Thió The applications of digital photography. Joaquín Montón Tool 5. Understanding structural damages Structural damages in Traditional Mediterranean Architecture. César Díaz Seismic risk in the traditional architecture. Giambattista De Tommasi The European-Mediterranean Seismic Hazard Map. María-José Jiménez The seismic behaviour of traditional constructions with masonry walls. Pere Roca Fabregat Tool 6. Understanding the processes of degradation of the materials used Identifying types of damp: the causes and the lesions they produce. Soledad García Morales Degradation of Building Materials (stone, earth, timber). Maria Philokyprou Various types of scientific techniques used to identify degradation mechanisms of stone. Mustafa Al-Naddaf Agents in timber degradation. Joaquín Montón

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II. Reflection and the project Tool 7. The criteria of intervention Criteria of intervention in traditional architecture. Fernando Vegas, Camilla Mileto Technical issues in housing rehabilitation. Michel Polge Choosing the project direction. José Luis González Moreno-Navarro The innovation value for quality in the traditional architecture rehabilitation. Fabio Fatiguso Notes on the rehabilitation and reuse of traditional and historical architectural heritage. Carlo Atzeni Rehabilitating and building using traditional materials. The Egyptian experience. Bernard Maury The dilemma criteria: The point of view of heritage value. Irene Hadjisavva-Adam Systems and equipment installations challenges. Athina Papadopoulou Tool 8. Rehabilitation techniques: reinforcing structures Rehabilitation of structural elements in Traditional Mediterranean Architecture. César Díaz Reinforcement and treatment of foundation. Egyptian experiences. Wahid El-Barbary

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Technological and structural aspects in the conservation of Old Akko. Ofer Cohen, Yael F. Na’aman Walls strengthen and treatment: the Egyptian experiences. Wahid El-Barbary Seismic improvement and conservation of structural features. Giambattista De Tommasi Reinforcing traditional Algerian structures to resist earth movements. Abdelaziz Badjadja Restoring traditional timber constructions: the Turkish experience. Banu Çelebioglu Tool 9. Rehabilitation techniques: consolidating materials Renderings: consolidation, restoration or replacement. Patrice Morot-Sir The treatment of damp in traditional architecture. Soledad García Morales Consolidation of the sandstone monuments of the world heritage site of Petra. Ziad Al-Saad, Fandi Waked Treating and protecting timber. Joaquín Montón Methods and substances for treating and repairing the wooden elements, the Egyptian experience. Wahid El-Barbary

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III. The work Tool 10. The reality of on-site work On-site reality. José Manuel López Osorio Job creation through restoration towards a sustainable community. Khaldun Bshara Some observations about Project Management. Athina Papadopoulou

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IV. Lifespan Tool 11. Maintenance of traditional architecture Support material for building maintenance: the “identity card”. Ramon Graus

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Introduction

Traditional Mediterranean Architecture

RehabiMed uses the term traditional architecture to refer to everyday architecture that is alive because it is inhabited, essentially civilian, domestic and of pre-industrial construction. It is a form of architecture built using local resources, which covers materials, techniques and the skills of its constructors, and it is the fundamental expression of the culture of the different communities and their relation with nature and the landscape. It is an architecture that covers different forms of grouping and the scattered habitat with all its auxiliary constructions, not forgetting the more modest elements (fountains, paths, etc.), which, altogether, form the traditional Mediterranean landscape. RehabiMed focuses broadly on this architecture, including both the rural habitat, fundamental to the humanization and structuring of the territory, and the city, the clear expression of life in community and the optimization of resources and human relations, going beyond the filters of highbrow architecture to incorporate all the values of more modest forms of architecture. Rural architecture is primarily linked to systems of agricultural and livestock production, which, beyond a simple presence in a bygone landscape, plays a vital role in understanding the processes that have produced today’s landscape, the result of a social and a natural history. Rural architecture has always played a salient role as an element that structures the landscape in which buildings, crops and nature are in perfect balance, the result of a continuous process of change and transformation, a socioenvironmental reality generated jointly by biophysical and socioeconomic factors throughout history. The traditional rural habitat takes the form of a heterogeneous variety of built typologies which may be scattered or form small settlements. It is also accompanied by a large variety of auxiliary elements and constructions that are vital to the domestication of the territory (cabins, dry-stone walls, ovens and kilns, caravanserais, fountains, wells, mills, stables, granaries, etc.), and infrastructures (canals, paths, irrigation channels, etc.) which are the result of the historical interaction between natural resources and human ways of appropriating them that bear witness to the coherent hybridization of the biophysical factors of a region and the socioeconomic factors of the community that inhabit it. Urban architecture, on the other hand, is built in the context of a city or urban settlement, being the expression of a more complex form of community dwelling, in which artisans and traders predominate over the land-related trades and where ‘the new needs and forms of society find their place’ (Mumford, 1961). The urban settlement, though also originally linked to the rural space and to the need to commercialize farming surplus, appeared as a structure to dominate the territory, defined by Braudel (1968)

Elmali, Turkey

‘more than by its walls or the number of its population, by the way in which it concentrates its activities on the most limited surface area possible’. The urban habitat covers a large typological range, derived to a large extent from geographical differentiation and from its origin and historical evolution. This historical and morphological diversity not only translates as buildings, construction procedures or materials used, it is also the configuration of the urban form, expressed in the way of structuring and considering collective space (streets, squares, etc.), of organizing constructions and uses which, in the rural world, are scattered (sanctuary, fountain, fortress, etc.), of relating private architecture and public space, developing a greater variety of residential typologies that reflects more complex social structures, in the uses of buildings, in the singularity of its infrastructures (market, school, etc.), and so on. These settlements, which in days gone by exclusively configured the city as a consequence of its growth and transformation, now form an integral part of the contemporary city, where they play the role of historical nucleuses. It is, then, the form of traditional architecture that humankind used to settle and construct its habitat in the territory around the Mediterranean Sea, a palimpsest permanently rewritten by the relations between people and their surroundings, and which has today become cultural landscape and collective imaginary.

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Introduction X

Qalaat al Manika, Syria

Hacienda Algarrobo, Malaga, Spain

Rovinj, Croatia

Lucca, Italy

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Introduction X

A changing world. Architecture under threat

The inventories drawn up as part of the CORPUS and CORPUS Levant (EUROMED Heritage I) projects showed in 2002 the farreaching transformations and pressures to which architecture, landscape and traditional territory are subject. Today, traditional surroundings are in a dramatic situation throughout the Mediterranean Basin, reduced to a continuing loss of their social and cultural character, threatened by intense degradation and constantly on the retreat. Likewise, the breakdown of the traditional world and the tendency to cultural homogenization as a result of globalization have brought about disregard for much of this architecture, often considered to be a symbol of poverty with values and qualities that are far removed from the mediatized concept of modernity. Pressure on the traditional habitat began with the process of industrialization, though it was much accentuated by the modern movement and urbanism in the early 20th century, seeking new models of dwelling and building cities that could overcome the deficiencies of traditional settlements; it went as far as denying all functional, social and even aesthetic values, and radically placed ‘the new’ before ‘the old’. This process emerged at different times according to the country in question and whether we refer to the urban or the rural space. Today, in the era of the ‘global village’, when the metropolitan industrial city is turning into a diffuse metapolis and the borders between country and city are becoming increasingly hazy, the pressure on this architecture and the population that it houses is even greater. In the rural environment, many villages are becoming depopulated due to the lack of alternatives for development, and others are subject to violent transformation under the pressures of property or tourism-related speculation without the necessary urban planning. This contemporary urbanism is upsetting the historical balance between humankind and nature, and converting the rural landscape into a landscape without activity, where traditional architecture loses its meaning and original function, and is reused and transformed. In urban environments, the ‘historical nucleuses’ are affected by different problems according to each historical and regional circumstance, which we could summarise according to four main vectors of pressure, sometimes complementary or simultaneous, and with differing degrees of influence: nucleuses in the process of overpopulation due to migration (south-north or country-city) with the subsequent physical (over-occupation and modification of dwelling), social (constitution of ghettos, insecurity, etc.) and

Arnavutkoy, Istanbul, Turkey

Mostar, Bosnia Herzegovina

environmental (insalubrity, lack of comfort, pollution) deterioration of the urban environment; nucleuses in the process of depopulation due to the abandonment of the historic fabric for the city, with the subsequent loss of social values and the deterioration of buildings and architectural heritage; nucleuses affected by heavy-handed urban renovation work (demolition of heritage, destruction of the historic fabric with the creation of new expressways, incoherent insertion of new architectures), and, finally, nucleuses affected by processes of urban reinvestment, in which we can distinguish three main processes: the development of tourism, tertiarization (especially in historic centres) with the possible loss of the residential function, and gentrification (the installation in a run-down neighbourhood of residents from a

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Introduction X

Tunis, Tunisia

Aleppo, Syria

high-income bracket), all processes that can have a counterproductive effect in social terms. Institutions such as the UNESCO and ICOMOS have issued repeated alerts about the loss of this heritage. In this respect, mention should be made of the recommendations of the International Charter for the Conservation of Historic Towns and Urban Areas (Washington Charter) of 1987 and the Charter on Built Vernacular Heritage (1999). Both charters, in addition to providing criteria for intervention, stress the need for long-term action in the form of education and sensitization measures, involving the promotion of training and specialization programmes in areas of preservation of traditional architecture, aimed at technical professionals and politicians, who should head policies for the assessment and rehabilitation of this heritage, and seeking the complicity of the population, an active protagonist and participant in this shared legacy. It is in this context that the RehabiMed project proposes a series of measures to encourage the rehabilitation of this architecture on the basis of sensitization and training.

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Introduction X

Rehabilitating Traditional Mediterranean Architecture

In its global dimension, traditional habitat has a great deal to contribute to a context of sudden changes and urbanization that is neither sustainable nor environmentally friendly, and is marked by a need for the reorientation of urban policies in order to reduce conflicts between humankind and nature, improve quality of life, encourage basic values of community life and call for the recovery of the existing territory and recognition of cultural diversity. For RehabiMed, the concept of rehabilitation covers a broad range of action with a view to recovering and updating a lost or damaged function—in this case, dwelling. On the basis of present-day concerns, rehabilitation means improving the action of dwelling by seeking a point of balance between technical aspects, the preservation of heritage values and criteria of social justice, economic efficiency and preservation of the environment (the three mainstays of sustainability). RehabiMed continues the task begun by the European Charter of Architectural Heritage and the complementary Amsterdam Declaration, both dated 1975 and promoted by the European Council. These documents put forward the concept of ‘integrated conservation’ for the recovery of run-down historic centres, based not just on the restoration of monuments but also on the promotion of actions to rehabilitate the fabric of dwellings and social measures. RehabiMed therefore proposes a methodology that addresses the rehabilitation process on the basis of integrating traditional space into a wider territorial context; from the global viewpoint of a multisectorial, economic, social and environmental approach; that is driven by a desire for coordination and calls for consensus of action between the various agents; that is flexible, due to the need for continual adaptation to changing realities; and, essentially, non-dogmatic, not claiming to produce single solutions to the problems of the traditional habitat in the Mediterranean, seeking instead solutions that adapt to the conditioning factors and specificity of each local context.

Thessalonica, Greece

Beirut, Lebanon

Istanbul, Turkey

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Introduction X

The RehabiMed Method on the scale of the building. The Guide and its constituent tools

Whereas the first volume of this publication is devoted to the RehabiMed Method and its intervention on the scale of villages, towns, cities and the territory, volume two is its complement, focusing on the scale of the building. It is, then, a text aimed at the architects, engineers and builders who design, direct and carry out rehabilitation work on traditional buildings in the Mediterranean. Rehabilitation of a building calls for an overview of the territory in which it is set and an understanding of its relation with the territorial and urban context. This is why the RehabiMed Project insists on the need to apply this Guide in the framework of the overall rehabilitation method outlined in the first volume of this publication, which sets out a series of shared, coherent criteria for intervention in order to address the complex problems involved in these situations. This second volume is also divided into two different parts: a methodology, which we refer to as the Guide, establishing procedures for the successful undertaking of rehabilitation work, and a practical part containing specific tools for concrete problems. The first part is the product of the joint work of a network of Mediterranean experts who, in the first year of the RehabiMed Project, drafted the basic principles and procedures of the Guide. The texts in the Guide have been debated at length after presentation at the 2005 RehabiMed Symposium in Marseilles, and constituted the conceptual bases for various training seminars in 2006 and 2007 (Nicosia, Cairo, Kairouan, Marrakech). The second part, comprising practical tools, was written by individual specialists in a variety of fields with a view to providing elements of support for the various phases of rehabilitation work. It aims to cover a broad range of problems and sensibilities which, in our opinion, characterize the Mediterranean basin. It is true that strict compliance with a guide of this nature calls for a high degree of commitment and may raise issues that are difficult to address according to the reality of a given country and place, but we are convinced that setting high standards will, in the long term, stimulate the quality of the rehabilitation of our traditional architecture and contribute to its preservation.

Dubrovnik, Croatia

La Selva del Camp, Spain

Cairo, Egypt

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First part The RehabiMed Guide to the rehabilitation of traditional buildings An integrated approach to the building


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RehabiMed Guide for Rehabilitation of traditional buildings

Objectives of the Guide

With the aim of rehabilitating traditional architecture in a conscious, orderly and adequate manner, this document offers the architect/engineer a guide1 to follow during the rehabilitation of traditional buildings. The way we have chosen, though not necessarily the only one, first of all defends the need to preserve the fact of ‘dwelling’, both in the sense of improving the living conditions of inhabitants and preserving the meaning of this architecture within the community. Secondly, it sets out to recognise traditional architecture as part of the Mediterranean cultural landscape. Its rehabilitation with a minimum rigour represents the transfer to future generations of heritage values (historical, artistic, memorial, testimonial, etc.). We have to point out that acting according to these principles calls for an arduous task of sensitization: of the technical professionals, because most of their university training is based on the construction of new buildings using reinforced concrete and industrialized techniques that are hard to reconcile with this architecture, and of the community, because it is vital for it to recognise the testimonial value of its architecture. To this end, we propose mechanisms for the community’s active participation in decision-making. TOOL 1

It is also a guide that sets out to be, as far as possible, ‘scientific’, ‘objective’ and ‘precise’, and one that places a great deal of emphasis on the initial phases of diagnosis and reflection prior to the project; it is a guide that disagrees with interventions in built environments carried out without a thorough knowledge of the building and its circumstances, on the basis of the fact that ‘this is how it’s always been done’; a guide that mistrusts the excesses produced by a blind faith in new technologies applied without criteria; and, finally, a guide that aims to cut back the habitual lack of economic control of rehabilitation work. It is quite true that for each specific building it is necessary to find the scale and scope of each of the stages proposed. The RehabiMed guide therefore presents a general outline of maxims to be adapted to each specific case. The guide takes as its starting point the premiss that if we do not know, we are unable to reflect and, therefore, we cannot rehabilitate. It therefore proposes four divisions of the process (knowledge, reflection and the project, the work, lifespan) within which the different stages of work are carried out. The aspects of architecture and construction proposed in a guide of this kind for the rehabilitation of buildings might seem to be well known to all, but the very fact that they are known often leads to false premisses in the various stages, and the quality of rehabilitation work tends to suffer. To close this introduction, we would just like to remind that this guide acquires its maximum value when it is applied in a broader area of action, whether on the scale of the district, the town or the territory, and as part of a coordinated action plan as proposed in the RehabiMed Method for the rehabilitation of traditional Mediterranean architecture.

Traditional architecture is extremely vulnerable to the pressures of the contemporary world. Its rehabilitation requires particular care to prevent its values from being damaged. Zuccarello, Italy

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The initial agents in the process

The foremost agent in any operation to rehabilitate a building is the owner, who may be public or private, individual or collective. In all cases, the owner represents the soul of the operation, the seat of the desire to improve a home, do business, simply keep a building standing, share in the collective enthusiasm of improving a street, etc. It is also important to remember that some or all of the dwellings in an apartment building may be rented, and the needs and opinions of the tenants therefore have to be taken into account. On the other side of the relation, the architect/engineer is the professional qualified to direct the various stages of rehabilitation with the collaboration of a multidisciplinary team. This guide uses the term architect/engineer, though in the Mediterranean context we find various professionals who are qualified, totally or partially, for this kind of work, such as the architect, the architect-engineer, the building engineer, the technical architect, etc. However, the complexity of careful rehabilitation work means that they are particularly trained and sensitized to these issues, as well as being open to the collaboration of experts from different disciplines (historians, anthropologists, restorers, topographers, etc.). The third agent in the process is the builder or contractor. The role and capacity of this figure is different all over the Mediterranean. In some areas, traditional know-how has completely disappeared, whereas in others it is still possible to build as it was done in the past. By protecting traditional Mediterranean architecture, we are also protecting these crafts.

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The phases of the Guide

RehabiMed observes how, in practice, the client decides on a series of improvements or changes to be made to a building and immediately undertakes rehabilitation work. In some cases, the client will consult an architect/engineer, but the result of rehabilitation is the reflection of the immediate needs of the moment. Some would argue that it has always been so, that this is an ‘architecture without architects’, but we all know that the organic growth of pre-industrial architecture responded to techniques and conducts that were distilled by tradition and carried out by true professionals, experienced workmen, whether master builders, masons or maalem, who all form part of a world that has practically disappeared. The proposal of the systematic participation of university-trained technical professionals may seem a frankly technocratic alternative, but we think it responds to the reality of the far-reaching social changes in the Mediterranean basin. All of these technical professionals have to be aware of the inevitability of most of these changes and the fact that, as Kevin Lynch2 reminds us, they will probably only be able to ‘manage transitions’.

As a rough guide, we might say that, while in general practice the process comprises just two phases (the decision to take action and the work itself), RehabiMed proposes a sequential procedure, a process in four consecutive phases that begins with the decision to act: I. Knowledge: any intervention must be preceded by knowledge of the building and its occupants. Stage one (1. Preliminaries) includes the client’s decision to take action but takes the form of a preliminary diagnosis that makes an initial, objective valorization of the proposal and the object of intervention (the building and its users). The complexity of the building usually calls for a second stage of knowledge (2. Multidisciplinary studies (Analysis)), based on meticulous disciplinary research to analyse3 social, historical, architectural and construction aspects. II. Reflection and the project: once knowledge of the building and its users has been acquired, we can go on to reflection, which represents a third stage, 3. Diagnosis (Synthesis), that synthesizes4 the information collected during the previous phase. This stage individually explores problems and their

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causes, and produces an overview of the building’s potentials and deficits. The fourth stage (4. Reflection and decisionmaking) picks up the client’s ideas for rehabilitation work and seeks to reconcile them with the reality of the building, its heritage values, economic possibilities for investment, etc. At this point the criteria of intervention are confirmed (how to conserve, to what extent to transform, etc.), and they must therefore be guided by a solid professional ethic. And, finally, on the basis of sound criteria, it is now possible to move on to the fifth stage (5. Project) and the drafting of the project document that enables the contracting, constructing and control of rehabilitation.

IV. Lifespan: it would seem that once rehabilitation of the building is complete, the process is at an end, but we also include a seventh and final stage, 7. Maintenance, which comprises minor cleaning work, repairs and renovations carried out according to a timeframe throughout the building’s lifespan until future rehabilitation (a major operation that will restore the building to the standards of the time). Particularly important in this stage are periodic inspections to detect deficits and new needs before the building begins to decline.

III. The work: Having passed through these two major stages, phase six (6. Rehabilitation), will be far more precise, preserving the values of the building, adapting better to the client’s needs and, though apparently contradictory, at a lower economic cost because the uncertainties surrounding work have been better defined. But in order to guarantee the quality of physical rehabilitation work, the contracting of the builder and his collaborators is vital, be they artisans, restorers or other specialised companies.

This graph shows the conceptual difference between rehabilitation and maintenance: from the moment of its construction, the building starts to age; if minor maintenance operations are carried out periodically, the building will age more slowly; finally, it reaches a point when the living standards of the time make it obsolete (what we call the end of its lifespan) and a rehabilitation operation will be necessary.

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As shown in this poster printed by Guarda City Council, although each of the street’s inhabitants carry out with the best of intentions operations that might be termed rehabilitation, without supervision, a guide or criteria of conservation, the street will ultimately be changed to the point that it is unrecognisable. (Câmara Municipal da Guarda, 1985, Portugal).


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1 Preliminaries

b e

This first stage brings together all the necessary contacts to begin a building’s rehabilitation process, once the client has decided to do so. The themes addressed are very varied in order to allow a sufficiently open initial approach to the general framework of the operation. This stage turns around what is generally called the preliminary diagnosis, a phase of orientation for the client. Decision to take action / Interview with the client This stage represents an open dialogue between the owner and the architect/engineer. The architect/engineer has to identify the client’s needs and desires, and detect possible ways of putting the idea into effect. It is important to bear in mind that the initial reasons for a commission may differ from the final decision. The owner will often consult an expert for a minor problem (a crack, damp, etc.), issues of comfort, municipal conservation requirements, etc., but it is the architect/engineer who has to be capable of orienting the owner in order to rationalize the intervention and perceive the more determinant needs which may

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different to the owner’s initial concerns. The owner may also have decided on rehabilitation of the building for purposes of financial investment, and in this case the architect/engineer has to be a good advisor with regard to the legal aspects and economic cost of the operation. Preliminary diagnosis TOOL 2 The key point in this first stage is the preliminary diagnosis. This involves an initial global approach to the building, its values (architectural, historical, etc.) and its problems (related to construction, habitability, etc.) by means of a preliminary inspection of the building. This first visit takes the form of a visual inspection in which the architect/engineer’s experience plays a fundamental role. A visit to the whole building will be conducted in an attempt to recognise the construction system used, its characteristic architectural values, the pathologies affecting it, associated social problems, etc. Particular attention will be paid to the load distribution and water drainage. All of this information can be compiled in one or various systematized inspection sheets. This is the case of the MER in France and Switzerland, and the Test Mantenimiento in Spain, etc. Some of these inspection methods have recently incorporated data associated with the building’s energy behaviour and other environmental parameters. In situations of major fragmentation of ownership of the building, a series of interviews is required to guarantee the participation of all owners and users of the building. Alongside the inspection, the architect/engineer has to investigate

During the first visit, the architect/engineer has to acquire an overview of the building’s problems (Como, Italy)

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the building’s legal status with a view to finding out the urban planning obligations and restrictions to which it is subject (permitted urbanistic use, level of listing, legal protection imposed by urban planning, mortgages, censuses, etc.) and the grants that may be applied for in the event of rehabilitation. The degree of heritage protection of the area and/or building is generally decisive to the operation. Initial contact with the corresponding authorities (municipality, regional administration, etc.) may help to clarify this context. It is also necessary to detect the legal conditions of the building’s occupants: low-rent tenants, occupied dwellings, sublet tenants, etc. The preliminary diagnosis report After inspection and legal consultations, the architect/engineer has an initial understanding of the building and will have detected its deficits and potentials. The preliminary diagnosis report may clearly include in summarised form the data collected, and must evaluate the building’s state of conservation and set forward recommendations. The expert may, then, from the start of the process, inform the owner of the possibilities of rehabilitating the building and technical and economic restrictions. At this point, the client has to decide whether to continue with his or her initial ideas or reformulate the intervention. This report may of course take the verbal form of an interview, but it is always best to make a written record, as the client may wait several months to make a decision or consult another expert, and the written word is always more precise. If the building is in a good state of repair and no major changes are foreseen, we can go straight on to stage 7 (7. Maintenance) and propose a preventive maintenance plan. However, 90% of cases call for a second stage of multidisciplinary studies before starting rehabilitation.


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2 Multidisciplinary studies (analysis) This stage of the process consists of the systematic collection of information in all the fields requiring research in order to produce full knowledge of the object of study. Conducting these multidisciplinary studies successfully depends on the training of the expert responsible for carrying out or directing them (the corpus of knowledge of the technical expert may, in the simplest cases, be concentrated in one person with, at some points, the consultation of various specialists). We cannot trust exclusively to our own experience and intuition, which, though very necessary, must be accompanied by the systematic collection of information, which, in some cases, will be backed by specialized tests. TOOL 3 Establishing of provisional hypotheses The multidisciplinary studies stage is fundamental to gaining sufficient knowledge of the building and its context before intervention begins. By this token, it is advisable to set the objectives and some initial hypotheses5 in accordance with the

information collated in the preliminary diagnosis report and to verify them as the studies advance. Programme of multidisciplinary studies These hypotheses will be taken as a basis to plan a feasible, coherent study campaign using the means available. At this point, the architect/engineer must be fully aware of the scale of the intervention (a small house, a large building containing many dwellings, a listed building of great monumental value, etc.). The work may also be staggered to allow subsequent verifications to be made of initial ones. By this point it should be clear who the director of all the studies is to be. Social aspects Depending on the type of rehabilitation, socioeconomic aspects may be crucial to the intervention. The basis for study tends to be a sociological survey to detect family units and possible problem situations (overcrowding, marginalization, unemployment, abandonment, etc.) and their relation with the district as a whole. According to the type of operation, the possibility of provisional or definitive rehousing of inhabitants with very close links to the municipality should be organized.

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Furthermore, in the world of traditional architecture, anthropology may provide us with valuable data about the social significance of the house, use of spaces, customs, etc.—all the intangible aspects related to the community’s perception of its architecture. In the case of constructions that are as fragile as traditional architecture, anthropological studies should be promoted to document forms of dwelling that are in danger of disappearing. The fact that many dwellings in traditional neighbourhoods are now inhabited by people emigrating from other traditions implies the need for knowledge of both cultures and the possibility of combining them harmoniously.

Historical aspects Architecture, and this also applies to the traditional form, is valued when it can be recognised as part of a tradition. The introduction of historical studies always helps to set far more solid criteria of intervention. First of all, the historical method explores documentary sources (notary archives, family archives, old photographs, past projects for the building) in order to compile data that helps to understand the building and its transformations. At the same time, the building itself is a splendid historical document that can be carefully studied as material culture using the archaeological method that is generally conducted alongside the graphic survey of the building (test drilling in walls, analysis of construction materials, stratigraphic analysis of the building, etc.). Another historical discipline, oral history, plays an important role in the rehabilitation of traditional architecture. Asking questions of the elderly may produce very useful data about the building and also about traditional construction techniques that are disappearing. Architectural aspects Without a good graphic survey of the building it is difficult for the architect/engineer to understand it and therefore to produce a project in keeping with reality. The level of complexity of the building and planned interventions will suggest the most suitable type of plan and its degree of precision. The type of survey may be manual (using a tape measure), topographic or photogrammetric. In all cases, all efforts must be made to produce a precise plan,

An understanding of the customs associated with traditional lifestyle is part and parcel of a careful approach to its architecture. The ethnographer Violant i Simorra studied the customs of the people of the Pyrenees before transformation.

Rehabilitating a building is not intervening in an object; a house is the reflection of the people who live there, and it is necessary to find out their concerns, aspirations and needs. Baakline, Lebanon

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Deeds, wills, bills of sale and old plans form part of a rich documentary heritage that provides first-hand knowledge about the history of a building. Santa Perpètua de Moguda, Spain, 1777 – ACA


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since it will provide the basis for all subsequent work. At the same time, good photographic or video documentation is extremely useful, since it retains elements that may go unnoticed at first sight. A graphic plan is not only an abstract measuring operation. Drawing the building is the best way to discover and understand it. An important part of the plan is recognition of the building’s architectural values and the graphic plan of materials, construction techniques and their pathologies from a construction viewpoint. TOOL 4 The way a 21st-century architect/engineer sees traditional

architecture is inevitably a present-day viewpoint marked by present-day concerns. It is important to take into account the fact that the very idea of cultural heritage is a cultural construction of the last 200 years. In this respect, the value and authenticity of traditional Mediterranean architecture, in all its diversity, cannot be valorized by a fixed criterion. The necessary respect for the cultures of the Mediterranean basis calls for an understanding of architecture in its tradition. The inspection will involve an unbiased study of the building’s architectural values (integration in the place, spatial configuration, singular structure, type of ornamentation, etc.), attempting to

The method of producing the graphic plan may be complicated by the characteristics of the dwellings as well as the degree of precision. Cave dwelling in Matmata, Tunisia – Institut National du Patrimoine, T. Dammak and M. Chakroun

An evaluation of the values and transformations of the traditional dwelling can be represented by the layers of finishes on the dwelling’s surfaces (floors, ceiling and walls). Dwelling in Tinerhir Ksar, Morocco – III Atelier de Réhabilitation des Kasbahs du Sud de l’Atlas

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In order to understand a building within the architectural tradition of the area, it is important to consult works of reference about local architecture (historical or typological studies, etc.). (J. Revault: Palais et demeures de Fès, CNRS, 1988, Morocco)

In order to discover spatial and constructional transformations, the architectural analysis has to be based on a historical analysis that dates and identifies stylistic influences. Building in Barcelona, Spain – àqaba.documentació històrica

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avoid fragmentary appreciations and seeking the unitary logic that produced the architecture. During this stage we recommend consultation of the completed studies about the building’s typology and, in some cases, the carrying out of further studies about singular aspects of the building. Traditional architecture is particularly characterized by the surfaces of its walls (colour, texture, irregularities, etc. of façades and interiors), making studies of colour and applied decoration very valuable. This will involve multidisciplinary participation, because the focus on the use of colour or applied paint calls for a study of the history, art and construction of traditional techniques. It is also important to remember that though change is slow in the pre-industrial world, a traditional building grows and is modified in keeping with the needs and means of each period. It is therefore advisable to study the building’s architectural transformations, once again with recourse to a historical study, in order to understand its present-day configuration. This stage will also require detailed consultation of the building’s legal and urbanistic framework. In the case of listed buildings, their records will be studied in order to understand why they are partially or completely listed.

A building tends to have a long life, and the exterior image may have changed several times in its history. Colour studies analyse the layers of painting and/or stucco on the façade with a view to discovering its original decoration and how it has evolved. Façade on the Rambla in Barcelona, Spain


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Construction aspects TOOLS 5-6 This stage includes the identification of all the building’s physical and construction elements, and observation of its lesions. Here we should point out that the training of architects and engineers since the 19th century has centred on the study of construction by subsystems (foundations, walls, floors, facings, etc.); in traditional architecture the building was constructed as a whole, and it is important to address it from this global viewpoint. This stage therefore calls for an architect/engineer who is familiar with the traditional construction methods of the region, with a solid scientific and technical training in the pathology of traditional buildings.

The approach to problems has to be as scientific as possible: detection of lesions, a preliminary hypothesis as to their causes and verification of these hypotheses. The architect/engineer will also have access to a series of experts (chemists, geologists, biologists, etc.) and tests (on site and in the laboratory) that will allow him/her to identify materials, possible alterations, monitoring of fissures, wood boring insect attacks, etc. It is particularly important to evaluate the building’s structural safety in order to avoid accidents. This involves soil investigation (by means of a geotechnical report if necessary), an analysis of the structural coherence of the whole and the structure’s load capacity. This evaluation is particularly essential in seismic areas, where a careful study of the building’s vulnerability is necessary. This is a particularly conflictive issue, since structural safety standards are designed for new constructions of steel and reinforced concrete, and it is practically impossible to assimilate them to the traditional reality. The dilemma of simultaneously conserving and making a building secure can be nuanced by knowledge of the building’s structural behaviour over long periods of time. When approaching the rehabilitation of a building, we recommend introducing criteria of sustainability and environmental protection. This involves analysing the building’s water and waste cycles and energy consumption, and studying winter and summer comfort levels. Mediterranean construction tradition has countless bioclimatic solutions that should not be undervalued due to ignorance of them during an intervention. This phase should not overlook verification of the building’s connectivity (state and position) with basic infrastructures (drainage, drinking water, electricity, telephone networks, etc.) in order to foresee from the start the effective possibilities of connection, which in some cases would call for work that is simply unfeasible.

An evaluation of the gravity of a building’s lesions calls for detailed knowledge of how the building was constructed. Thessalonica, Greece, 1997 – Manos Anagnostidis, Maria Dousi, Olympia Hatzopoulou

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3 Diagnosis (synthesis) Critical evaluation of studies The diagnosis6 stage involves a task of synthesis and critical reflection that is based on the multidisciplinary studies carried out during the previous stage. This evaluation has to lead to unitary planning to avoid excessively fragmentary results due to limitations on the material available. In order to organize and establish information it is always necessary to place it beside other information and highlight it. For example, superposing it graphically over the geometric plan of the building. Three types of maps can be systematically drawn (in floor plan, elevation, section): firstly, a map of values with notes about the spatial, colouristic, historical and artistic values of each part or the whole of the building; secondly, a map of deficits with notes on the building’s social problems, features, and lesions and degradations; and thirdly, the map of former and/or existing uses showing how the building was and is used before intervention.

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The diagnosis phase must bring together all information in orderly fashion (plans of values, deficits and previous uses). The team of Professor Luigi Zordan at the Università degli Studi dell’Aquila (Italy) has developed a ‘reasoned guide’ offering examples of how to represent this data in order to produce a judicious diagnosis (Luigi Zordan: Le tradizioni del costruire della casa in pietra: materiali, tecniche, modelli e sperimentazioni, 2002).

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Confirmation of hypotheses The initial evaluation should produce an overview of the building and confirm the hypotheses put forward at the start of multidisciplinary studies, based on observations and tests. However, it is always possible to raise new hypotheses (initial hypotheses not subsequently confirmed, appearance of new conditioning factors, etc.) and return to the study phase in order to verify them. Writing a report At the end of this stage it is once again necessary to establish, in writing, the knowledge gained about the building. This report will list the building’s composition, describe and justify its values, list its deficits and their causes, and offer recommendations. The diagnosis report will always be written on the basis of individuation of problems and their causes, according to the criterion of technical impartiality. This is a reasoned expert report and must be written so that other technical professionals external to the process can understand it, but it must also include a summary that can be understood by a non-professional reader. The conclusions must be clear, concise and complete. This note will specify the strong and weak points in order to show the potential for rehabilitation of the existing building.

Beside, a map of the original uses of a building produced by a historical study. Antic Hospital de clergues de Sant Sever, Barcelona, Spain – àqaba.documentació histórica

At the end of this stage we will have a report on the state of the building that lists the causes of its deterioration, abandonment, etc. (Istituto de ricerca sul legno, Florence, Italy)

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4 Reflection and decision-making Feasibility Now, with a perfect knowledge of the building and its users, it is possible to study the feasibility of the client’s ideas. A further dialogue will take place with the owner about his/her future needs and economic possibilities with regard to the potential of the existing building. The feasibility study will be based on three partial studies: 1. What we call the transformability map, which simply compares and contrasts the maps of values, deficits and previous uses produced in the last stage, showing which parts of the building would be subject to changes (eliminations, additions, alterations, etc.) and which parts should be conserved to preserve their value; 2. The programme of new uses proposed by the client (the brief) and rationalized (surfaces, relations between uses, etc.) by the architect/engineer; 3. The evaluation of regulatory conditioning factors associated with parameters of urban planning and listing of cultural objects.

And, finally, it is time to go back to the client’s ideas and analyse their feasibility. Meeting at Selva del Camp Town hall, Spain

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Another two examples from Professor Zordan’s guide show us how to graphically represent what he calls the map of transformability and processes of compatibility with a view to reflecting on the integration of new uses.

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Continuity of use is generally accepted as the best way of protecting this architecture, though in some cases its revitalization involves a change of use. It is important to suggest sensible changes of use, since some proposals may involve the practical total loss of the values of traditional architecture. Confirmation of criteria TOOL 7 As commented above, due to its great diversity, traditional Mediterranean architecture cannot be approached with fixed criteria. In this stage, the architect/engineer has to establish the criteria to be applied to the project (additions, eliminations, priority of aspects of habitability, reintegration of lost parts, reversibility of risky interventions, consolidation of ruined parts, etc.). Initially, neither extreme should be dismissed: pure conservation or pure restoration. The Charter on the Built Vernacular Heritage represents a first general framework to consider7. Decision-making Having confirmed the criteria, the compatibility of the type of intervention has to be considered, striking a balance between improvement to the inhabitants’ living conditions, safety of the structure, safeguarding heritage values and the available economic resources. And, finally, the decision can be taken, with full knowledge of the type of rehabilitation work (from conservation to restoration).

Three examples of buildings restored according to different criteria. Lefkara, Cyprus / Thessalonica, Greece / Damascus, Syria

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5 Project

Outline proposals The outline proposals are a stage of comprehensive dialogue with the client, during which it should be possible to activate the participation of the inhabitants or users of the building. It will gauge which of the various planning alternatives best adapt to the proposed alterations and the existing building by applying the criteria outlined during the previous phase. From the start, particular attention will be paid to compliance with the legal framework. Finally, the client will reach an informed agreement as to the type of intervention contained in the project. Project TOOLS 8-9 The working drawings will describe the intervention in sufficient detail to be able to follow administrative procedures, contract the work and carry it out without deviating from established costs. The project interprets the criteria of intervention and applies a series of technical parameters for the physical construction of the intervention.

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The outline proposals phase systematically studies the alternatives for the integration of the new programme of uses into the building to be rehabilitated. One method is J.N. Habraken’s, which studies the flexibility of spaces on the basis of what he calls the theory of supports, used in some European rehabilitation work (J.N. Habraken: Denken in Varianten, het methodisch ontwerpen van dragers, 1974).


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As a general rule, therapeutic intervention in a building’s problems must address the causes, not just the symptoms. The choice of a traditional or a modern technique will also depend on the kind of builder who is contracted. It is now a question of finding out whether traditional techniques are still used in local construction and whether it is possible to recover them to carry out rehabilitation. Here we would like to mention a trend in theory that we think could usefully be adapted to the rehabilitation of traditional architecture and which centres on a necessary knowledge of traditional techniques for responsible intervention in this form of architecture. It includes the works by the Compagnons du Devoir in France, studies on timber structures (Carpintería de lo blanco) by Enrique Nuere in Spain and, most particularly, by Paolo Marconi in Italy, who has put this knowledge to practice in the Manuale del Recupero. The Manuale documents local construction tradition (generally of a municipality or homogeneous region) and presents professionals with forms of traditional intervention. Another step forwards taken in Italy is the Codice di Pratica which introduces methods of analysis and intervention in traditional architecture (structural consolidation, earthquake, etc.), seeking to reconcile traditional construction and more modern techniques. These documents should be consulted during this phase and their

The design of the project calls for consultation of publications on local construction (Paolo Marconi: Manuale del Recupero del Centro Storico di Palermo, 1997 / Antonino Giuffrè and Caterina Carocci: Codice di Pratica per la Sicurezza e la Conservazione del Centro Storico di Palermo, 1999)

The project specifies interventions to consolidate and reinforce the building in sufficient detail on the right scale. Reinforcement of the timber floor of Can Plantada, Spain – Cristina Gonzalo Diego

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recommendations followed when working on the project. It was these documents that launched the debate in Italy about the use of modern techniques to reinforce and consolidate old structures. During the design of the project, the impact of each of the techniques used will be studied, along with their compatibility with the existing building and the final visibility of the intervention. The same pains should be taken when integrating modern installations into the building. From the outset, measures must be taken for their integration without detracting from façades and interiors, for example by proposing specific layouts. The project also has to incorporate such parameters of sustainability as are reasonable for the scale of the intervention (water- and energy-saving measures, introduction of renewable energies or facilities for the correct management of domestic waste, etc.). At the same time, each of the design decisions will study what is now called the maintainability of construction solutions—that is, ensuring that all elements are accessible for subsequent ease and safety of maintenance. The most obvious example is a window that is practically impossible to clean, etc. The project must be detailed but open to modifications justified by discoveries made during rehabilitation work. It will include the following documentation: geometric definition of the proposal with measurements (floor plans, sections and elevations), plans of the structure, finishes and installations, technical description, bill of quantities, budget, technical specifications, and health and safety measures.

Some municipalities have a traditional colour card for reference when drafting the project. L’Escala City Council, Spain

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Work on recovering façades specifies colours but also the type of chemical product to be used and how to apply it and control the quality. Façade in Barcelona, Spain – Chroma Rehabilitacions Integrals SL


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III. The work

6 Rehabilitation Tender action In order to guarantee correct rehabilitation, the choice of the builder or contractor is very important. In some regions it is still possible to find builders who are familiar with and use traditional construction techniques, though they are, sadly, fast disappearing. In some cases it may be possible to train the builder(s) in specific techniques, but in most cases it is simply not possible to use certain techniques because of their economic cost. If working with a construction firm that has little specialized knowledge, particular attention must be paid to the contract in order to supervise materials and techniques. The type of contract will guarantee the quality of work and the professionalism of the builder(s). Some tasks of cleaning delicate walls or artistic works call for the temporary contracting of restoration professionals using specific methods and techniques.

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III. The work X

Obtaining the building permit The programming of rehabilitation has to take into account the waiting time for the relevant authorities to issue permits. In the case of listed buildings, waiting times may be longer. The report may also be unfavourable, necessitating a return to the project phase. Carrying out the work TOOL 10 Works direction in the case of a traditional building calls above all for flexibility and dedication. Unforeseen events tend to arise as work is carried out, and it is difficult to only apply what is indicated by the project. The follow-up of the work may, then, allow the ongoing revision of the project and reinterpretation of the building in the light of new discoveries, which, in some cases, may call for changes to the project. The project describes construction solutions to reinforce, consolidate or renovate an element. During work it will be necessary to establish mechanisms to verify the suitability of the construction solution and its correct functioning. Important aspects to follow up are initial considerations, economic supervision, and control of the effectiveness of solutions to reinforce and coordinate the safety of work. During work a mechanism will have been established to produce a dossier about all the work carried out, upon completion. This comprises a series of plans that reflect how the rehabilitation as built. This document is vital for documenting work in accordance with the Venice Charter but also for organizing a maintenance programme (see stage 7). There are also a series of organizational aspects of the work that have to be taken into account, ranging from the programming of

When organizing the work site, it is useful to put up a notice board showing the main plans to ensure an overview of the process and pinpoint problems at all times. Beit Baluk, Damascus, Syria

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work to the planning of the entry of several trades, to studies of site accessibility (a great deal of the work is carried out in the narrow streets of historic centres), interior work using small machines (low heights, narrow passages, etc.), foreseeing the protection of certain parts of the building from the elements and rehabilitation work itself, and avoiding accumulation of workers. Furthermore, it is difficult to envisage demolition operations on a rehabilitation site; these will in fact be deconstruction or dismounting operations. At the start of work, elements to be dismounted for reuse will be marked (collecting tiles, timber beams, etc.) and measures will be taken for the correct disposal of site waste. The project supervisor must at all times supervise dismounting work and take the necessary safety measures to avoid accidents due to partial imbalances in the building or the appearance of materials or products that are dangerous for health (asbestos cement, asbestos insulation, electrical transformers with PCBs, etc.). Handover of the work Upon completion of the work, legal procedures will be carried out to consider it finished and, in some cases, to apply for grants. It is important to use this stage to analyse the management, construction and compliance of the project with planned uses. Though at this point some aspects can be corrected, this feedback stage should serve to improve the project phase for subsequent commissions; no opportunity to learn from mistakes should be wasted.


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Stratégie

IV. Lifespan

7 Maintenance

As we have commented several times, traditional architecture is extremely vulnerable. Custom has been responsible for its conservation (whitewashing during spring celebrations, checking tiles after high winds, etc.), but socio-cultural changes in today’s world (the culture of disposability) have accentuated the abandonment of this form of architecture. If the need for rehabilitation has arisen, it is due in part to such abandonment. Having made the effort to undertake rehabilitation, it is important to make the most of the opportunity to promote its upkeep, because on the very day rehabilitation work is completed, the building starts to age. Publicizing the building’s values among the community The breakdown of the traditional world and cultural homogenization have led to disregard for much of this architecture as a symbol of the poverty and backwardness of its

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IV. Lifespan

population. Once rehabilitation work is complete, it has to be a priority to acquaint the community with its values and make them part of its rehabilitation. Each case will be different but it is important to promote some kind of sensitization activity to show the value of the work carried out (a small event to show how work was carried out, publication of photographs of before and after rehabilitation, publication of the work in the local press, etc.). Choice of the model of maintenance An initial definition of building maintenance would be the series of periodic tasks carried out in order to conserve it, during its lifespan, in suitable conditions to cover foreseen needs. Maintenance is habitually associated with the idea of repairing damaged elements, what we call corrective maintenance, but what the RehabiMed method proposes is to think in terms of planned and preventive maintenance. Planning involves the preparation of a calendar of maintenance operations, and preventing means carrying out maintenance operations before the construction element deteriorates.

It is a good policy to promote care of rehabilitated housing by instituting public initiatives that value heritage. 1987 Prize for the whitest street, Serpa, Portugal

Maintenance extends the lifespan of buildings and slows the ageing process. Cairo, Egypt

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The ‘identity card’ TOOL 11 In order to systematize this way of organizing maintenance, we propose to give the building an ‘identity card’, a document that compiles all the information about the building and incorporates a timeframe to programme maintenance operations. This card will be presented to the owner (in some cases to all the tenants) so that recommendations can be followed. In most cases, the architect/engineer who completed work and is perfectly acquainted with the building will prepare the information about the building and a timeframe of maintenance operations. Information about the building will comprise the dossier as built (see previous stage) and recommendations for use of the building. The timeframe will also programme maintenance operations for the coming 10 years (cleaning, inspections, repairs and renovation). The timeframe should also indicate who will carry out these tasks (the user, a trusted builder, an installer, a specialized firm or the architect/engineer). These cards can also be used to make a note of maintenance operations carried out, incidents that have taken place and alterations made, so that with the passing of the years it becomes a record. The ‘identity card’, a kind of clinical record about the building, will also in the long term provide invaluable information for the conservation of and future interventions in the building.


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IV. Lifespan X

Maintenance work according to a timeframe The operations programmed on the calendar will include a series of periodic inspections by an architect/engineer to evaluate the building’s safety (for example, in relation to detachment of façades, risk of gas leaks, structural deformations) and reprogramme the timeframe. In some cases, it will be possible to detect serious problems in time and propose the repeat of the entire process (1. Preliminaries). In this way, the architect/engineer will become, like a family doctor, the ‘general technical practitioner’ with the building among his or her records, thereby ensuring long-term sustainability of what is now a complete rehabilitation project.

1

To guide: ‘to go before, showing a path’.

2

LYNCH, Kevin: What time is this place?, 1972.

3

Analysis: ‘distinction and separation of the parts of a whole in order to discover its principles and elements’.

4

Synthesis: ‘composition of a whole by the joining together of the parts’.

5

Hypothesis: ‘a provisional theory or supposition taken as the basis for research to confirm or deny its validity’.

6

Diagnosis: ‘act of deciding the nature of an illness by observation of the symptoms and signs’.

7

Guidelines in practice of the Charter on the Built Vernacular Heritage, ratified by the ICOMOS 12th General Assembly, in Mexico, October 1999: ‘1. Research and documentation Any physical work on a vernacular structure should be cautious and should be preceded by a full analysis of its form and structure. This document should be lodged in a publicly accessible archive. 2. Siting, landscape and groups of buildings Interventions to vernacular structures should be carried out in a manner which will respect and maintain the integrity of the siting, the relationship to the physical and cultural landscape, and of one structure to another. 3. Traditional building systems The continuity of traditional building systems and craft skills associated with the vernacular is fundamental for vernacular expression, and essential for the repair and restoration of these structures. Such skills should be retained, recorded and passed on to new generations of craftsmen and builders in education and training. 4. Replacement of materials and parts Alterations which legitimately respond to the demands of contemporary use should be effected by the introduction of materials which maintain a consistency of expression, appearance, texture and form throughout the structure and a consistency of building materials. 5. Adaptation Adaptation and reuse of vernacular structures should be carried out in a manner which will respect the integrity of the structure, its character and form while being compatible with acceptable standards of living. Where there is no break in the continuous utilisation of vernacular forms, a code of ethics within the community can serve as a tool of intervention. 6. Changes and period restoration Changes over time should be appreciated and understood as important aspects of vernacular architecture. Conformity of all parts of a building to a single period will not normally be the goal of work on vernacular structures.’

The maintenance timeframe programs operations over the year and indicates which professional should carry them out. (Carnet d’entretien, PI-BAT, 1991, Switzerland)

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RehabiMed Guide for Rehabilitation of traditional buildings X

go to

Good state, without new needs

1

7

= programme maintenance plan Good state, with new needs

PRELIMINARIES

MAINTENANCE

= extend studies

Decision to take action / Interview with the client

Preliminary diagnosis report

Preliminary diagnosis Visual inspection of building

Habitability problems = extend studies

Conservation problems (obsolete) = extend studies

Identification of users

Important value for the community (listed) = extend studies

I. KNOWLEDGE

(building and users)

Start of participatory process

Serious problems of habitability (overcrowding, fire security)

Legal framework of building and users

go to

2

= extend studies Serious problems of structure

MULTIDISCIPLINARY STUDIES (ANALYSIS)

= evacuation and extend studies

2

Social aspects

Historical aspects

Socioeconomic

go to

Study of documentary sources

approach

MULTIDISCIPLINARY STUDIES (ANALYSIS)

Anthropological approach

5

3

Archaeological method

PROJECT

DIAGNOSIS (SYNTHESIS)

Oral history

Programme of multidisciplinary studies

Outline proposals Architectural aspects Graphic survey

(building and users)

I. KNOWLEDGE

Technical parameters

Construction system

Integration in the place

Project

Construction aspects

Degradation phenomena

Typological analysis

Structural and fire security

Spatial analysis

Comfort parameters

Colour and decoration study

Environmental parameters

Legal and urbanistic framework

Infrastructure connectivity

Documentation

Planning alternatives

II. REFLECTION AND THE PROJECT

Establishing of provisional hypotheses

Incorporation of ideas from the participatory process

Agreement with the client

Local construction knowledge

Working drawings

Visibility of the intervention

Production information

Technological compatibility

Bill of quantities

Integration of modern installations

Budget

Sustainability

Technical specification

Maintainability

Health and safety measures

return to

2 MULTIDISCIPLINARY STUDIES (ANALYSIS)

3

6

DIAGNOSIS (SYNTHESIS)

REHABILITATION

Obtaining the building permit

Critical evaluation of the studies

Follow-up

Handover of the work Organization

Choice of the builder

Building’s composition

Ongoing revision of the project

Programming of works

Effectiveness of the construction solutions

Protection of building

Call for tenders

Description of studies carried out

(historical, artistic...)

Justification of building values

Building contract

Evaluation of new discoveries

- from the elements - from the rehabilitation work itself

Map of deficits Description of deficits

(social, features, lesions...)

Training workers

Diagnosis Map of former and/or existing uses Recommendations

Decisionmaking

4

42

Carrying out the work

Writing a report

Map of values

Programme maintenance plan

Contracting specialists

7

7

MAINTENANCE

MAINTENANCE

Improve energetic performance and comfort

Maximum conservation

Avoid accumulation of workers

Information about the building

Maintenance work according to a timeframe

Dossier of work as built

Cleaning

Recommendations for use

Inspections

Adapt the maintenance programme

Repairs Preventive maintenance

Improve basic equipment and supplies

Programme of new uses

Dossier of work as built

Choice of the model of maintenance

Improve environmental performance

Transformability map (values + deficits + existing uses)

Reuse of materials, waste control...

The ‘identity card’

Improve basic habitability

Confirmation of criteria

Coordination of works safety

go to

Rehabilitate the façade and/or the roof

REFLECTION AND DECISIONMAKING

Feasibility

Confirmation of hypotheses

III. THE WORK

II. REFLECTION AND THE PROJECT

Tendering process

Corrective maintenance

Extensions, change of use

Maintenance timeframe Cleaning

Repairs

Inspections

Renovation

Renovation

The building needs further rehabilitation

Structural consolidation Evaluation of regulatory factors

Maximum transformation

Seismic consolidation

Fire prevention

go to

5 PROJECT

Complete rehabilitation

IV. LIFESPAN

II. REFLECTION AND THE PROJECT

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Publicizing the building's values among the community

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1 PRELIMINARIES


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Second part The RehabiMed tools An aid to the rehabilitation of traditional buildings


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I. Knowledge


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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation


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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation


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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation

Traditional Mediterranean Architecture. Territory, landscape and traditional architecture

To speak of a Mediterranean territory is to refer to a diversity of landscapes in which sea and mountains are involved in constant dialogue and reach out to each other, in a geographical formation marked by a series of territorial contrasts—the fertile and the desert, mountains with plains, rough and smooth, plateaus with riverbanks, coastline and inland—where the hand of humankind has shaped the urban and the rural. The Mediterranean is a space where human activity over the centuries has used and shaped the territory, leaving marks, traces, landmarks, references, the products of its historical development. Cities, towns, villages, caseríos, estates, temporary settlements, cabins, tents, refuges, etc., with miscellaneous arrangements, spaces and organizations, are the forms of human dwelling in this territory. Added to these are other non-residential arrangements, dissociated from the dwelling and associated with productive uses (farming, stock-keeping, forestry, pre-industrial, etc.), or other collective and private needs and services. The network of roads, for vehicles, people on foot or livestock, along with natural watercourses, aided by ports, wharves, moorings, etc., interlink and communicate settlements and places. In addition to the hydraulic network, artificially created to harness the territory’s water resources, these constitute the organization of the space constituted by the terrazgo and the montazgo, with their divisions and limits, and a variety of scattered built elements, a structured territorial complex with those settlements and arrangements. All this is the result and reflection of prolonged interaction throughout different historical epochs and societies between humankind, nature and the physical environment. Bearing witness to the relation of developing communities, individuals and their environment is the creation and shaping of landscapes in territorial spaces of cultural interest, known as cultural landscapes—territories in our geographical scope, in the materialization and personalization of which traditional architecture has a significant role. It is important to clarify that professional specializations (urbanism, architecture or engineering) apart, I understand architecture in a territorial sense, following the definition provided by William Morris in the second half of the 19th century, as a series of alterations produced on the surface of the earth at the service of human needs. This broad definition embraces and ties up with the architectural concept of cultural landscape, including settlements at their various levels of size and complexity, buildings, infrastructures and the various treatments presented by urban and rural non-built spaces.

I. Knowledge

José Luis García-Grinda Doctor of Architecture Professor of the Department of History and Theory o Architecture at the School of Architecture of Madrid (Technical University of Madrid), Spain

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Landscape of rural settlements with farmed terraces: Estellecs (Spain)

When referring to traditional Mediterranean architecture, the house is the heart and the symbol of this organized architecture as a whole, in both urban and, particularly, rural settlements. It is conceived as the seat and the heart of traditional life and activities, and, in the words of Viollet-le-Duc, in architecture as a whole, the home is what best characterizes the customs, tastes and uses of a people—the way it lives and feels. Set on its own site, it may be accompanied by buildings or parts of buildings that meet the various artisan, farming and commercial uses and needs. The actual estate or private property may also include, though separate from the house or on common land, a whole range of buildings of this kind, which go to define the characteristic traditional architecture of each comarca or territory. The house in this sense is not just a physical structure, it is an institution created for a complex set of ends, and its construction can be qualified as a cultural phenomenon. It is, then, not unusual in traditional

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I. Knowledge

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architecture for the concept and actual name of the house to be used to identify not just dwelling place but also the estate as a whole and its associated properties, seen as a symbolic place of coexistence and production. These auxiliary architectures vary a great deal in their nature. They basically serve farming or livestock functions or provide back-up for these productive activities, separated from the house for reasons either of function or hygiene, such as stables, sties, ovens and kilns, granaries, silos, barns, drying sheds, storehouses, threshing grounds, cellars, dovecots, apiaries, refuges, etc. There are also others that respond to the same needs but are collective in use or ownership, such as granaries, refuges, livestock pens and folds, etc., some of them permanent and some used in transhumance. Another group of architectures provides facilities or public services to the community, often adopting traditional forms and organizations, and, on occasion, forming part of the housing programme. In some cases, these architectural elements were the property of the council or collective associations, sometimes also providing revenue for them to support the development of their activities. These included various types of fountains, wells,

Tool 1 Knowledge of traditional architecture as a basis for rehabilitation Traditional Mediterranean Architecture. Territory, landscape and traditional architecture

cisterns, tanks, deposits and supplies of water for human and animal consumption and watering, such as washing places, water troughs, pools, aqueducts and irrigation channels, and the constructions and mechanisms that extract water from its natural courses and wells, such as dams, millraces, crankshafts and waterwheels, for services such as the forge, the smithy and the kiln. Others provided infrastructure for hunting activities, such as hides, kill sites or pits to catch bears, wolves or other “vermin”. The architectures of civil and religious institutions were represented by the town hall, with various facilities for education, justice, food supplies, trade, lodging, health, sport and celebrations, such as

House in Languedoc and Provence (France), with dovecot, drawing by Viollet-LeDuc

Caseríos in La Axarquía (Spain), based around modern raisin production

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Alquézar (Spain), Al kassar, a town founded in the 13th century beneath the 10thcentury castle of Arabic origin


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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation Traditional Mediterranean Architecture. Territory, landscape and traditional architecture

schools, prisons, pillories, counsel trees, markets, souks, shops, guilds, almudís, corn exchanges, fondouk or khan, salt storehouses, pósitos, tithe barns, tercias, hostelries, inns, taverns, hostels, baths, hospitals, poorhouses, hospices, bowling alleys and pelota courts, complemented in some cases by private activity. The specifically religious included churches, mosques, synagogues, oratorios, sanctuaries, wayside crosses and cemeteries. Pre-industrial architecture dedicated to production, which may be listed under some of the previous headings, included mills driven by beasts of burden, water or wind, olive-oil mills, presses, paper and sugar mills, smithies, coppersmith’s, water-driven sawmills,

I. Knowledge

fulling mills, saltworks, pottery, glass, iron, lime and plaster kilns, different artisan workshops, textile mills, tanneries, dyers and forges. Extraction activities covered mines, quarries, kilns and mineral-panning sites. There was also the organization and elements of certain road infrastructures (actual roads, cart tracks and paths, livestock tracks, paths, or bridges, pontoons, footbridges, sewers, etc.) and systems of irrigation and those associated with sailing and fishing activities, such as ports, wharves, shipyards, moorings and hatcheries. Another heading was the treatment of public space (pavements, steps, ramps, roofs, pergolas, benches and vegetation), elements to form and enclose farming space, such as terraces, fences, hedges, walls, enclosures, gates, etc., or these elements organized to this end, exemplified in such exposed spaces as some African oases, where the palm grove becomes a solar roof, beneath which fruit trees grow, and the lower level becomes a vegetable garden, feeding on the structure of irrigation channels, enclosed by dense palisades made of palm branches that protect it from the desert sands. Added to these organizations are the public spaces they form, which, in both the urban and the rural worlds, are notably complex. They are defined and organized by significant buildings and elements, with specialized uses linked to a whole range of activities (public, civic and religious, representative, commercial, festive, productive, access-related, etc.) in squares, avenues, gardens, streets, alleys, dead ends, open drains, atriums, fountains, watering and washing places, tracts of land, threshing grounds, crossroads, fords, etc.

House in the country; masia in Cassà de la Selva (Spain)

Landscape of terraced crops in La Alpujarra, Ohanes (Spain)

The humanization of the landscape: Bentarique (Spain)

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I. Knowledge

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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation Traditional Mediterranean Architecture. Territory, landscape and traditional architecture

This represented a whole series of architectures ranging from a degree of organizational and constructional complexity, the building of which called for the participation of artisans or specialist tradesmen, to other, more basic examples, which were simply built by the individual in question, alone or with the help of others. In short, a complex and varied body of architecture that gives the Mediterranean territory its own specific identity, reflecting both local specificity and cultural relations in the architectural forms that were the result of historical exchanges, and in which each part, no matter how small, goes to shape the character of these different Mediterranean landscapes that can

truly be termed cultural. The Charter on the Built Vernacular Heritage drafted by ICOMOS in 1999, a continuation of the Venice Charter, provides in its introduction a summarized characterization of this cultural product, tabling an incipient territorial vision:

The human scale in rural landscapes: caserío in Santa María de Nieva (Spain)

Salobreña (Spain), Greek settlement on a former island, with the sugar cane plantations, of Arabic origin, and the Arabic and Christian town centre, crowned by the citadel

Farming caseríos, Ecija (Spain)

Sanctuary of Sidi ali El-Mekki (Tunisia)

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“The built vernacular heritage is [...] the fundamental expression of the culture of a community, of its relationship with its territory and, at the same time, the expression of the world's cultural diversity.


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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation Traditional Mediterranean Architecture. Territory, landscape and traditional architecture

Vernacular building is the traditional and natural way by which communities house themselves. It is a continuing process including necessary changes and continuous adaptation as a response to social and environmental constraints.�

Values of traditional mediterranean architecture Traditional Mediterranean architecture can be characterized as a pre-industrial product, set in both the urban and, particularly, the rural environment, where, until well into the 19th century, urban

I. Knowledge

phenomena were dominated by the rural nature of their surroundings, based on production and evolution within the mechanisms of tradition and therefore associated with a specific territory. The process of designing and constructing this architecture was based on models that varied in accordance with individual experiences, needs and possibilities. These variations mean that in many cases we are dealing with open models, characterized by the presence of significant shared elements, forms or parts. Some authors even consider types as such not to exist, contrasting with the so-called primitive vernacular architectures, products of societies with little stratification and limited economic and social development, in which the types are more closed and constant. The forms used by the latter are present in the Mediterranean area above all in the form of refuges, cabins, shacks and tents, adopting elementary organizations that exist alongside the most complex traditional architectures. Models are the result of the collaboration of many people for generations, including those who used them and those who constructed the buildings. In this respect, there are no actual designers, since everyone was familiar with the models. However,

Section of a dovecot, a specialized construction in cereal-growing areas, Fromista (Spain)

Farm and storehouse, Valle del Mejerda (Tunisia)

Waterwheel, washing place, drinking trough and irrigation channel in a row, Pozo de los Frailes (Spain)

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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation Traditional Mediterranean Architecture. Territory, landscape and traditional architecture

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Forge machinery in Compludo (Spain)

Troglodytic oil press, Galipolli (Italy)

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Watermill adapted to low water levels, Huebro (Spain)


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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation Traditional Mediterranean Architecture. Territory, landscape and traditional architecture

I. Knowledge

specialist craftsmen were habitually involved in their construction due to their greater specific knowledge of both architecture as a whole and the more complex or specialized parts of their construction. Builders, stonecutters, masons, roofers and thatchers, carpenters and ironsmiths are some of the specialized workers involved, who often incorporated details and know-how taken from the historical architecture of designers, even interpreting and integrating certain aspects to make their built work stand out from the rest. Architectural form therefore adapts to given problems, to specific needs and available means, without conscious aesthetic effort, though some buildings present distinguishing decorative features that mark them out, economic possibilities permitting. It is based on the idea that a common task should be carried out in the simplest, most direct and least troublesome way possible, in a society linked to tradition in which changes occur within a given shared inheritance and hierarchy of values, reflected in the types of buildings. Its form is characterized by being a product of use rather than change, marked by its capacity for aggregation and its openness and flexibility, easily allowing for modification and

Agricultural waterwheel in the river Orontes, Shaizar (Syria)

Public spaces protected by arches can be used as a place for gatherings and doing business, Ciudadela (Spain)

Windmills in the port of Rhodes (Greece)

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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation Traditional Mediterranean Architecture. Territory, landscape and traditional architecture

growth. By this token, it is conceived as something simple, clear and easily comprehensible, in which tradition is expressed as a form of collective control, even in the field of architecture, as a form of respect for others and the environment. A decrease in the presence of tradition and greater economic development are related to the greater individual evolution and diversity of the house, reflected significantly in the differentiation and progressive specialization of living and work spaces, particularly as of the Late Middle Ages, with the appearance of differentiated rooms for

daytime, sleeping and eating, and even summer and winter.

An enclosure and roof for livestock; fold in Sesnรกndez (Spain)

Simplicity and cleanness of detail: drain on a terrace, Arcos de la Frontera (Spain)

Collecting rainwater in a dry climate: rural cistern, Los Almagros (Spain)

Classical influences in traditional architecture: house in Minorca.

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Historical cultural relations across the Mare Nostrum are often imprinted on traditional architecture in the presence of elements and organizations that link architectures from relatively distant geographical areas in the Mediterranean, qualifying their exclusive local specificity. In Spain, for example, the concave undertile, known as an Arabic tile, which evolved from the Roman tegula, is significantly referred to as an Andalusian tile in North Africa, as a


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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation Traditional Mediterranean Architecture. Territory, landscape and traditional architecture

I. Knowledge

result of the arrival in those territories, especially in the 16th and 17th centuries, of the Moors expelled from the Iberian Peninsula, while the different circumstances of its presence in other Mediterranean territories give it local names. This architecture uses local materials such as stone, earth, timber and other plant matter, establishing a close relation with the environment and the place. This use of locally available materials directly relates economy and effort with durability, in accordance with the available building technology and knowledge. Their use is governed by a hierarchy of quality and durability of the material, depending on the budget and the symbolic and functional role of the built work. It is not unusual for the most expensive, longlasting materials to be reserved for the main façade, while the remaining façades, parts and auxiliary constructions, of less symbolic importance, are built using cheaper and less durable materials. It is the use of local materials that determines greater continuity of the different construction types, also influenced by evolution. It is also important to bear in mind significant changes produced by a variety of phenomena, such as the replacement of plant matter in roofs and visible structures due to fire risk in relatively recent times in many places in our territory. Exceptionally,

we know of the transport overland and by river and sea, since ancient times, of certain special materials—timber, stone and marble—transported from one side of the Mediterranean to the other. The calceranite from the impressive quarry of El Haouaria in Tunisia, extracted since Punic and Roman times, was loaded directly onto boats waiting in the caves created at the sea’s edge. Timber from the Cuenca mountain range was, in the 10th century, transported downriver to the east coast of Spain and the Arabic ports of Denia and Valencia, where it was used to build ships and buildings, and exported to Egypt. Traditional architecture works with the place, both in establishing settlements, seeking prime orientations and preserving fertile land, and in laying out the house. In the latter case, it adapts knowledge of the microclimate, using simple passive systems based on the thickness and colour of masonry and differing layouts, sizes and coverings of openings to seek protection from inclement weather. The overall shape of the building and its roof responds differently to wet or dry climates, with pitched roofs and projecting eaves or terraced or flat roofs. There were also specific heating systems, with large kitchens that fulfilled their primary function as well as comprising the centre of domestic life. The

Coloured renderings in evolved cave dwellings: neighbourhood of La Chanca in Almería (Spain)

Complements for the house: communal oven, Zalduendo (Spain)

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Curved Arabic roof tiles derived from the Roman tiles, with different shaped imbrexes and channel tiles, Aldea Quintana (Spain)

Tool 1 Knowledge of traditional architecture as a basis for rehabilitation Traditional Mediterranean Architecture. Territory, landscape and traditional architecture

Spanish example of the gloria, a successor of the Roman hypocaust, is a response adapted to deforested cold areas, where a closed hearth with practically no oxygen allows the slow burning of small products such as straw. The harnessing of ventilation to produce through draughts or the construction of fireplaces to draw hot air out of the downstairs rooms can be found in the warm areas in northern North Africa and the Far East, drawing the coldest air from lower-lying north-facing areas, as specific adaptations in places where climatic conditions are adverse. Natural plant materials were incorporated into façades and patios to produce increased climatic comfort with their shade and moisture, complemented by construction elements to enhance their effects. This form of architecture also takes into account the specific experience of some places as regards natural phenomena, such as earthquakes and tremors, generating structures that seek defence from their destructive effects, such as double parallel structures in the façade and roof, independent of the latter to prevent it falling in, based on the flexibility of timber structures, present in the east in Greek and Turkish examples, corresponding to the meeting of the Eurasian and Anatolian Plates. Another example is the incorporation of flexible joints implemented horizontally along the masonry walls or at the building’s corners, comprising joists and

Plant materials: fence to enclose and protect the oasis of Douz (Tunisia)

Timber and stone: floor structure in the Alpujarra, Pampaneira (Spain)

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Brick: Mudejar influences in Nezta (Tunisia)


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right-angled pieces of timber. Solutions of this kind are present in various examples of architecture in North Africa, and they are even used in the architecture of Turkish tradition in the Egyptian maritime centre of Rosetta, in a clear example of historical exportation. One of the frequently cited contemporary values of popular Mediterranean architecture is its function, thanks to these simple yet intelligent climatic adaptations, as an example of the new bioclimatic architecture. Here, constructional passivity combines with adjustments to sunlighting and the creation of systems incorporating ventilation, the creation of shade and moisture, and complementary heating systems in which biomass is the energy resource generally used, as methods used by this form of architecture to improve comfort in response to the climatic conditions. Nor is there any shortage in the rich and diverse array of Mediterranean architecture of solutions that might be termed anticlimactic. The houses in the Alpujarra, in the mountainous region of Granada and Almería in southern Andalusia, feature a characteristic terrace-type roof—not, apparently, the most ideal solution in this mountainous territory with high precipitation and no lack of snow in winter, with some settlements at an altitude of

Cultural transmission and influences: a balcony protected by latticework, the application of the Arabic ajimez to colonial architecture in the Canary Islands, Icod de Los Vinos (Spain)

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over 1,500 m. This distribution, along with an organization of compact houses, without courtyards, is in fact the cultural residue of dwellings of Berber origin that can be related to those in the Moroccan Atlas. The construction and correct functioning of these terraces is based on the use of a purplish impermeable clay, with a high proportion of manganese, called launa, applied in various layers over floor tiles supported by wooden beams. This represents a complement to public space, very limited due to the orographic difficulties inherent in these settlements on steeply sloping mountainsides, using terraces as an open-air workplace and a space to hang out products to dry. Along with judicious adaptation to and respect for place, the use of time-honoured artisan building techniques involving the controlled use of local materials and the reuse of any useful construction element in existing constructions makes traditional architecture a useful contributor to sustainable development. It certainly expresses and conserves the knowledge, accumulated and handed down over generations, of the huge diversity of historical construction techniques based on different varieties and characteristics of the local materials used. This shared body of traditional knowledge can be regarded as a true cultural legacy of building know-how in the Mediterranean, an intangible heritage to add to that of tangible reality, clearly applicable to the recovery

Stone: mooring points or nerois in the port of L’Escala (Spain)

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and restoration of historical architecture. It is a form of knowledge on occasion tinged with ingenuity, since it uses solutions that are not strictly orthodox in technical terms, but that do offer a freshness and even a primitivism that gives them an appeal of their own. Local materials and traditional artisan techniques in themselves represent a major economic potential. The implementation of processes to recover and rehabilitate this architecture generate qualified labour, constituting a market even in areas where there is no industrial labour alternative, as in much of the Mediterranean rural world.

Gloria stove and trivet in a cave dwelling, section, Castrojeriz (Spain)

Gloria stove and trivet in mountainous area (Spain), drawing by Leonardo Rucabado, early 20th century

Climatic use of vegetation: orange tree in the courtyard of an Andalusian-style rural, Testour (Tunisia)

CaserĂ­o with terraced roof in the Alpujarra, TrĂŠvelez (Spain)

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The urban courtyard as a climatic regulator and a generator of shade and ventilation, Arcos de la Frontera (Spain)

Street covered by projections in the Alpujarra, Pampaneira (Spain)

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The attraction of traditional architecture for modern architects, as a source of inspiration for their language, is directly related to the simple, rational treatment of many of the solutions it employs, in a direct relation between form, function and built reality. This simplicity in the treatment of its forms that merely seek to respond to specific needs or solve a given problem gives traditional architecture an absolutely modern concept of formal beauty, in which reason adopts the form-function binomial. It is no surprise that masters of the Modern Movement such as Frank Lloyd Wright, Le Corbusier and Alvar Alto drew on this source. More recent figures, too, such as Hassan Fathy and Barragรกn, have used constructional and plastic forms in their new architectures with a marked desire to introduce references to it. The pure, cubic, white volumes of some traditional Mediterranean architecture have served as a reference to much of the modern architecture produced since the 1920s. Regionalist eclecticism, too, in some countries, generated an alternative to this modernity, at the same historical moment, with architectures that combined motifs taken from traditional models in a search for a national architecture as opposed to the internationalization of the Modern Movement. Their forerunners, the supposed pioneers of the Modern Movement, such as the Arts and Crafts movement in the second half of the 19th century, took as their inspiration the vernacular buildings of the Middle Ages to generate a new architecture based on artisan production. Even earlier, at the time of Neo-

Terraces and chimneys in the Alpujarra, Capileira (Spain)

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Reuse of old stone materials: Bosra (Syria)

Direct, rational solutions as a paradigm of modern beauty: Lucainena de las Torres (Spain)

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A washing place built with reused elements, Arcos de la Frontera (Spain)

Simplicity of form and volume as the inspiration for modern architecture: cemetery at Casabermeja (Spain)


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The white cubic houses that inspired the language of modern architecture: rural dwelling in Ibiza.

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Classical architecture and the European Enlightenment, traditional constructions were frequent references in the search for picturesque and rustic models, with a premium on diversity and variety of elements as opposed to the rigid classical norm, creating architecture of recreation or pleasure in country gardens and mansions. Today, some sectors of contemporary architecture continue to refer to popular architecture as a symbol of the local, with their sights set on sustainability and bioclimatic and ecological solutions as opposed to globalized or decontextualized languages, seeking specificity and architecture linked to the place, in a globalized world where identity is often sought in the local. There is no doubt that traditional Mediterranean architecture continues to establish itself as part of the built cultural heritage, as part of historic centres or singular architectural sites, and as singular or ethnographic examples, because it constitutes the historical legacy of our lifestyles in a process that has not been without difficulties and losses. As cultural heritage, it also has significant economic potential, complementing built and natural heritage as a knowledge and leisure resource. It is, however, equally true that in some Mediterranean countries it has ceased to be produced for some decades and in others, though still alive, it might be considered, to use a naturalist simile, a species threatened by extinction.

Rehabilitation and mediterranean rural space

The Swiss Cottage is a thatched cottage ornĂŠ designed by John Nash in the early 19th century. Inspired by traditional architecture, it sought the picturesque as opposed to the rigidness of the Neo-Classical architecture of the time, Cahir (Ireland).

The rural space is the most fragile as regards traditional Mediterranean architecture, with the phenomena of abandonment and destructive transformation related to the growing influence of the urban environment, subsequent emigration and abandonment of rural settlements, and the cultural and economic changes associated with globalization. The mass introduction of industrial materials unknown to traditional practice, the incorporation of introduced architectural types together with new housing demands and needs, and changes in production now taking place in the rural environment, as well as the abandonment of part of the habitat, in the context of the transformation and loss of collective and individual traditional rural values, mean that traditional architecture is in serious danger of disappearing from this space. Here I refer not only to the house, but also to much of the auxiliary architecture, particularly that which is associated with traditional productive processes, that fall into disuse as a result of growing industrialization and modifications to farming, livestock and forestry uses, and other facilities for miscellaneous communal needs. In short, what has been transformed or is threatened by substantial transformation is this architecture as a whole, understood and structured in the form of rural landscape.

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Rehabilitation as a mechanism for the recovery of traditional architecture must not, then, be based solely on urban settlements, but most particularly extend to the wider rural environment, at its different scales, from the viewpoint of the territory as a whole. Of particular importance here are the instruments of territorial organization associated with sustainability, affecting settlements of different levels and sizes, their public spaces, the individual scale of each building and detailed architectural treatment, with attention both to the house and to the auxiliary architectures. Rehabilitation has to be understood as a complex technique of recuperation, which pays attention to architecture at its different scales and complexities, integrated into an approach or even an overall programme of local sustainable development, requiring the confluence of different disciplinary viewpoints and experiences and citizen participation. As well as professional training in the specific techniques of rehabilitation, user recognition of this form of architecture as a part of culture and identity is key to its future. Only that which is familiar and valued will be conserved and handed on to future generations. This calls for campaigns of explanation and dissemination to present rehabilitation work to the population. Careful rehabilitation work speaks far louder in the rural environment than a thousand speeches or articles, because it illustrates how intelligently rehabilitated traditional architecture provides levels of habitability in keeping with contemporary expectations and requisites. This process accords importance to the role of the local artisans with their knowledge of traditional construction techniques who can pass on their specific know-how by means of specific experiences of rehabilitation, contributing their expertise to the training of future rehabilitation experts. Traditional architecture is a cultural and economic resource and the basis for sustainable development, and its rehabilitation represents a lever in these rural communities, as opposed to models of new construction, that avoids the occupation of agricultural land. The growing pressure of tourism and its associated new uses has to be used intelligently and channelled in such a way as to promote the rehabilitation of this form of architecture and avoid unsuitable environmental and sociocultural transformations of local communities. Some of the early Spanish experiences in this field showed how rural tourist accommodation can distinguish different territories by recovering and rehabilitating traditional architectures. Their inclusion in programmes of sustainable development is the key to establishing each territory’s visitor capacity in environmental and socio-cultural terms in order to retain a balance between visitors and local population, given the limitation and fragility of resources. Tourism has to be one element more contributing to local economic activities without necessarily becoming a monoculture, though it can act as a catalyst to set everything else in motion in depressed areas. Quality, locally managed tourism scattered across the 64

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Urban rehabilitation, recovering coloured renderings, Villajollosa (Spain)).

The reconstruction of significant traditional architectural features as tourist attractions: marshland dwelling in El Rocío with a reed roof, Doñana National Park (Spain)


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Rehabilitation of a rural water complex as a tourist attraction. Section of the mill and hydraulic ironwork in Teixois as part of a rural development programme carried out in the 1980s.

Traditional architecture and activities rehabilitated as a living museum: an artisan paper mill at Capellades (Spain), cross section.

territory, which conserves local resources and rehabilitates heritage, is basic to compliance with parameters of sustainability and non-conflict with the recuperation of traditional architecture. The specific consideration of cultural heritage necessarily involves an appreciation of the architecture of the specimens conserved, with their different levels of quality and durability, and must qualify the different interventions. Rehabilitation involves the transformation and partial destruction of the targets in order to give them a new lease of life, and the key is to establish which parts and elements should be completely preserved and what should be the tolerable degree of transformation in order to prevent loss of identity. There will also be examples that, due to their singularity in terms of architecture, history, ethnography, function or landscape, etc., are the object of careful restoration and conservation, included in architectural restoration policies and given uses that are compatible with their integrated conservation, and provide a specific explanation of the traditional lifestyles they served. The role in the landscape of some territorial elements must also be considered. They may even be the object of reconstruction and interpretation, in the case of significant examples that have disappeared, which may be important to the history and culture of a specific territory. Obviously, many examples should be the object of renovation and replacement, for reasons of conservation and obsolescence. The debate in these cases is deciding which are to be characteristic of the new architecture, seeking the conservation and integration of characteristic typological and construction features, with attention

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Traditional architecture as tourist accommodation: hotel in a cave dwelling in Matmata (Tunisia)

Traditional architecture rehabilitated for rural tourist accommodation: thatched cottages as bed-and-breakfasts, Adare (Ireland)

Rehabilitation seen as an overall architectural and territorial operation, including constituent elements, the settlements, their dwellings and constructions, the elements of public space and their integration into the natural setting, etc. Baget (Spain)

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to the experiences of climatic adaptation and values of sustainability, with no need to produce folkloric falsifications of traditional architecture. Like any human product, traditional architecture has not remained unchanged over time; it, too, has been subject to evolution, qualified throughout its transformative slowness by tradition. It is possible to identify evolving lines, with the incorporation of some exceptional innovations, where the new architecture can be integrated without its presence necessarily signifying the destruction of the image of the places and the rural landscape. These architectures constitute a historical legacy of the way we live, and in many Mediterranean countries they call for specific attention to the issues of valuation and rehabilitation in order to avoid the process of destruction and disappearance that they usually suffer. Now, at the start of the 21st century, it seems to be necessary to extend pilot rehabilitation operations applied to the rural territory, choosing settlements and significant architectural types of an exemplary nature, in order to complete and step up the recuperation work that is usually undertaken in urban historical centres.


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Traditional Mediterranean Architectures: collective values

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Michel Polge Chief architect and urbanist Technical Director of the Agence Nationale de l’Habitat (ANAH), France

The use value-heritage value binomial seems to be marked by conflict, exclusive choice or Manichean debate. It could be represented by another old conflict (for the French, at least): engineer versus architect, or even “replacer” versus conservator. An ideological approach to these debates will get us nowhere. If, on the other hand, we table the issue from the viewpoint of other questions such as continuity, reparability or improvement, we see constructions as what they are: existing, used, reusable. Then we can work on the margin of adaptation of these constructions, on their cultural value and the conditions of their sustainability. 1.1 The century when the Mediterranean opened up again The second half of the 19th century was a period of transition. The Mediterranean once again became an active commercial focus after several centuries during which conflict had limited trade. After the Renaissance, with the colonization of America, Atlantic trade supplanted Mediterranean commerce, and trade in the Mediterranean was largely restricted to large blocs: the Ottoman and the European Mediterranean, at the same time limited by conflicts between or within these blocs. For better or for worse, human and commercial exchange were reactivated in the Mediterranean in the 19th century with Europe’s ever increasing influence over the southern Mediterranean, a hold that went hand in hand with declining Ottoman power in both the north and the south. The Westerners colonized and developed commercial exchanges, going as far as opening the cul-de-sac that was the Mediterranean via the Suez Canal, restoring its interest as a commercial route that went beyond its intrinsic economic capacities. In the late 19th century, the Mediterranean was once again “globalized” and industrial Europe began to spread its models in a process that did not end with colonization. Until the 19th century, expertise spread with the men who bore it, slowly, adapting it to local resources and materials and pre-existing know-how. Andalusian Renaissance architecture, both the “highbrow” and the “popular”, is a remarkable example of technical syncretism and evidently things did not stop in Andalusia: the Spanish then transported their own know-how to America, the French adopted examples of Spanish stereotomy and developed them, and so on. But with the advent of manufacturing, it was the products that then spread, and on a very large scale. Factories were needed to produce them, and production initially took place where there was coal, but it later spread everywhere, following engineers and traders. Those responsible at local level for the actual building process merely had

Deir el Qamar (Lebanon)

to learn the process. From this point on, globalization of construction and architecture models took over at a scale that had not existed since the Roman Empire, that great disseminator of models. Industrial production made the process of standardization even more radical. 1.2 The paradoxical destiny of the Marseilles tile As of the 1850s, and for several decades, merchant ships set sail from Marseilles with mechanically produced tiles that were loaded in the hold as ballast and then sold in ports. So, in Algiers, Beirut, Istanbul and even Odessa, roofs were tiled with this new material. Houses began to be roofed with “Marseilles” tiles when the need had not hitherto been felt, even more so in countries that traditionally had terrace roofs. Why was this? There are probably many reasons, the least of which are technical. Marseilles tiles did not, for the southern Mediterranean, represent “progress”, in the sense that they were not a material that replaced another without needing thorough changes in expertise. The roof structures built in Beirut before the 1914-1918 war show that there were no local roof-building traditions adapted to this new material, nor did the people master the use of this exogenous material (minimum slope, etc.). In fact, the Marseilles tile was used in southern ports as decoration. It was probably appropriated as the sign of foreign architecture imported from the rich and powerful countries of the time. Cement, industrially produced bricks, metal roof structures—new techniques were to follow, with no regard for

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Suez Canal (Egypt)

pre-existing know-how. These imported novelties marked a before and an after in traditional architecture: this is how it was done before and this is what is disappearing... 1.3 The boom in manufactured products With the Mediterranean back on powerful trade circuits, moving beyond traditional areas of exchange, the phenomenon of industry came into its own. Industry mass-produced construction materials cheaply and could transport them far and fast by train and ships. Manufactured products flooded the market, and another process came into play: the artisan as the local actor in construction gradually lost his “plural” know-how and either disappeared or started to use industrial materials. Industry sought to eliminate any obstacle to the use of its products: complex implementation was one such, so there was a need for products that were simple to use and implement, but used on a large scale to encourage a large output: big companies were called for, with a highly specialised labour force with few qualifications—the complete opposite of the traditional artisan industry. Traditional means of construction—the work locally of artisans— could only have stood up to this onslaught if they were perceived as a value... but they were not. Just as in the first countries to be industrialised, the countries newly “conquered” by manufactured products saw first how local architectures became hybrids and gradually disappeared, in an outward movement from the town to the country. The idea that pre-industrial construction has a value in itself is a recent one, a “distant” idea never acknowledged by those who inhabited it when it was still flourishing: they were either rich and sought novelty as a visible sign of their wealth or were poor and rejected what seemed to be the material sign of their condition. From this point on, for several decades, traditional architecture was a theme for picture postcards and artists attracted by the picturesque before it was flattened by the new urbanists.

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We must not judge this phenomenon in hindsight. Indeed, today we see traditional architecture from a considerable distance: there are several generations between those who saw it built and ourselves, and we are no longer swept along by the religion of progress that caught up the engineers and architects between 1850 and 1970. Furthermore, what remains of this traditional architecture is the best part: the bottom-of-the-range constructions, built with few resources and little expertise, have disappeared, just as the worst built architecture of the industrial era will disappear. We sometimes tend to see the past and its material signs as a marvellous civilization, a kind of paradise lost. These past societies probably were charming—for a very small percentage of the population. Likewise, it is pointless to set the virtues of artisan production against the vices of industry. The traditional architecture that remains today must interest us for its use values, its capacity to adapt to milieus, its value as testimony. There is, however, no point in promoting it by comparison with what has come afterwards. 2.1 What does traditional architecture mean? Various features characterize what is usually termed traditional architecture: It is the architecture of artisans: its models are those of “in the style of”, models that are physically close and visible. It is, then, an “apposite” architecture. It is architecture without architects: their work was reserved exclusively for the important commissions of the powerful: monuments, palaces, and so on. Architects used highbrow models from books and treatises: they were essentially utopian in the etymological sense. It is an architecture that uses resources (materials, etc.) that are extracted or produced locally. This is another reason why it is “apposite”. It is an architecture which, for cultural and economic reasons, evolves very slowly, hence the misconception that traditional architecture is immutable and timeless. It is a rural rather than an urban architecture, because the urban is, by nature, more open to innovation, novelty, interchange and cultural crossover. It is an architecture that is generally left out of histories of architecture, which tend to be more open to architect’s architecture and monumental, highbrow architecture—that is, the architecture of power. Of course, there were no strict divisions between architect’s architecture and artisan’s architecture; they influenced each other, the latter trying to copy the former, and the former being obliged to use the technical know-how of the latter. Traditional architecture—it would perhaps be more accurate to say traditional architectures—is, then, the result of the production


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processes of the pre-industrial age. As such, it exists as the result of these processes rather than of a deliberate decision. The very fact of speaking of traditional architectures, of inventing this concept, means that there is a historical breakaway from those forms of production. To speak of traditional architectures is, in this sense, a convenient modern concept, despite being a simplification: if there is such a thing as traditional architecture, there is also a form of architecture that is not traditional. We have seen how the architecture that followed the rupture caused by manufacturing and its mass diffusion is, effectively, quite different. Yet even before this time, construction was subject to tensions, evolution and the comparison between highbrow and popular (or between architect’s architecture and artisan’s architecture, definitions which are, evidently, not value judgements). In order to be exact, then, it would be better to speak not of traditional architecture but of pre-industrial and industrial means of production, as we await the post-industrial, which, I hope, will consider both processes for the greater advantage of what is now called sustainable development. 2.2 The interest in traditional architecture The usual responses are varying and contradictory: Heritage is interested in the value as testimony of the physical signs of history. The French law on historical monuments, for example, refers explicitly to “the general interest from a historical or artistic viewpoint”. This is primarily a cultural reasoning.

Early 20th-century cement tiles by the firm Escofet (Spain)

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Nostalgia is critical of modern society and admires old-fashioned lifestyles (once considerably idealized). From this point of view, the idea is to conserve and protect what remains, and preserve technical expertise. Its discourse is one of beauty as opposed to the truth of heritage. Its intention is often mixed with identitarism, insisting the signs of local old societies, regretting the apparent standardization of today’s world, turning from this fact to heritage, driven by the passion of finding the differential element. This is a more idealistic stance. Commerce realizes that heritage is, potentially, mass merchandise. Functionalism recognises the use value of old constructions and centres on the issue of need to make the old building respond to the criteria of present-day quality in association with economic aspects: the functionalist emerges with the disappearance of the illusion of the tabula rasa as a preliminary for constructing the city of tomorrow. This is a realistic stance. The heritage and functionalist approaches are the two “positive” approaches that can serve as a reasoned way of addressing the issue of built heritage, its conservation, transformations, rehabilitation and improvement. These two approaches are, in theory, complementary rather than contradictory, since they bring together the notions of use value and cultural value. This is even more the case if we add the notion of sustainability, which brings us to: rehabilitation is better than reconstruction, improvement is better than reconstruction, sustainable is better than ephemeral, thrifty is better than extravagant, renewable energies are better than fossil energies, etc. Yet the path is not as smooth as it apparently ought to be... The nostalgia or cultural identity approach seems in theory to be a rather unconstructive, reactive attitude. Unfortunately, this approach often creeps into the “positive” approaches (notably those of heritage), confusing the truly historical approach of heritage and an aestheticizing approach that is all the more dangerous as it is highly subjective. The purely commercial approach is related above all to tourism. For the purposes of this article, suffice it to say that tourism is obviously a good thing for its economic effects, provided it does not destroy the things it is based on. If there is a plea to be made for the rehabilitation of traditional architectures in the Mediterranean, and elsewhere, it is that the different “positive” approaches work together: the cultural/heritage approach and the functionalist/use values approach. The idea, then, is to combine conservation and improvement without overemphasizing, forgetting or denying the economic side. A rehabilitation policy that costs more than new construction would be socio-economic nonsense: buildings are, primarily, to inhabit, to be worked and lived in, not to be looked

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at. Likewise, a rehabilitation policy that produced housing or workplaces that were markedly less adapted to modern life than new construction would merely sentence itself to death. It is important to know how to both conserve and improve. Perhaps the happy medium lies in sustainability: we all know now that there is no future in the overconsumption of resources as it continues to be practised today. 2.3 An example of pointless conflict between heritage and functionalism: windows In rehabilitation operations in France, windows are often the cause of tension when it comes to replacement. So, why do windows need replacing? The first reason is dilapidation due to a lack of maintenance, errors in the initial conception or, simply, wear and tear. In this case, it seems—in France, at last—normal to throw out the old frame and install a new one. The idea of repairing an old window on a normal building site would not occur to anyone. I recall seeing some lovely 18th-century casements sent to the rubbish tip simply because no-one had thought to look for a joiner—supposing there was one in the area—who knew how to repair the bottom part (weathering, sill cove, subsill), as a new in-set window was going to be installed anyway to improve thermal performance. The second reason is to save energy. There is a great deal to be said about ways of addressing energy saving in older properties. Technical solutions are still the field of great debate, but there is no space here to add to it. Suffice to say that energy saving is a major public issue everywhere, that existing housing is frequently a very “bad pupil” in this respect (in France, in any case), and that windows are, by definition, an aspect that cannot be neglected.

Gokçuogen (Turkey)

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There are just two solutions: to produce new energies or improve the performance of the existing. So the windows are replaced, as no one knows how to repair existing quality windows and reinforce them (for example, with double glazing). Suddenly, instead of addressing good technical solutions for repair/reinforcement, the debate turns to aesthetics: using glazing bars, using wood... “Wood” is the automatic reflex reaction: but are we sure that the wood we use today to make windows, for the products it contains, for its source, be it known or unknown, is automatically as sustainable as all that? Should we not take the issue a little further? This takes us to the limits of our practice: the aesthetic question is obviously the least important, though it is bought to the forefront, and the real technical and heritage issue is left to one side in the absence of suitable technical solutions: as far as I know, it is only very recently that the Danes started to bring a more sustainable approach to this issue: conserving and repairing existing windows with a production chain for this purpose, reinforcing the fittings to obtain better performance. This example serves to show how the rehabilitation debate is easily distorted when the heritage and the use-value approaches are brought into conflict rather than combined. As in many technical issues in rehabilitation, compromise is necessary, in the positive sense of the word, leaving to one side the aesthetic questions that are, by definition, subjective. In the above example, the questions to ask are: Is the existing window valuable in terms of heritage (for reasons of age, construction technique) and, if so, how should it be repaired and conserved? In this case, how can its heat- and soundproofing performance be improved: by reinforcing the fittings? With double-glazing? In this case, what is the appropriate approach to associated issues such as ventilation? If the original window is not conserved, what should it be replaced by and, most of all, using what material? When we ask this kind of question, the aesthetic issue is returned to its normal place: secondary. Which it always has been: no architecture treatise of the past treats the issue of windows and their design any differently to the most rational of engineers. The important question for a traditional joiner, whether working for an architect or a humble client, was how to allow in as much light as possible, using highly transparent glass in large panes to limit the number of glazing bars and, furthermore, at an affordable price; how to produce large opening leaves that were as rigid as possible, and how to ensure that the fastening was rain- and windproof (invention of half-round tongues and grooves in the 18th century, for example). The beauty of traditional windows lies in the possibility of manufacturing rational, efficient, sustainable


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products. This is the lesson to be learned, rather than their supposed aesthetics. By approaching the issue in this way, we would avoid the olde worlde windows we see all too often in protected areas, which satisfy neither the historian nor the technical expert.

3. Traditional architecture: what are the advantages today? The above arguments show various reasons to rehabilitate traditional architecture. Firstly, and this is the value most recognised by both the “informed� and the general public, it has a value as testimony, a heritage value: to conserve it is to conserve a memory, not for the sake of nostalgia or identity, but because it is a human need to establish oneself in time and, in order to do so, to retain signs of it in the form of physical traces. This is why conquerors seek to destroy not only people but also their monuments and towns. The destruction of Warsaw was a drama representing this point of view. But ordinary architecture cannot serve merely as testimony. It cannot comprise empty shells conserved as museum pieces. There are monuments for this purpose, in the primary sense of the word. Architecture is, above all, functional, and this is its only legitimization. The failure of urban renovation policies in the years after World War II demonstrates the need to maintain and rehabilitate old towns. It soon became apparent that the systematic destruction of old centres to build completely new districts was merely a dangerous illusion that merely by building everything anew it was possible to create a better world. This utopia, in the etymological sense of the word (remember, in the 1950s, urbanists thought they should build for the coming 30 years, then demolish everything and rebuild it all even better) rapidly came up against reality in the form of the economic impasse of this approach, not to mention human reactions. That reaction was so strong that it has often led to the opposite extreme: the desire to conserve everything, to condemn concrete (there is a curious ideological confusion between forms and material), to imitate the styles of old towns and architectures, as though the town were merely an abstract stage set (all things considered, the error of pastiche is the same as that of the old partisans of the tabula rasa: believing that the form generates the content). Knowing how to rehabilitate means knowing how to demolish, because it requires a choice.

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But it is not enough to conserve: it is also necessary to improve. Traditional buildings have used the means available in successive ages to translate the needs of these periods. These needs are not immutable; no one would agree to live today in the same conditions as two or three centuries ago if there is access to what the present day can do better. To improve is to take into account constantly changing needs as regards safety, hygiene, energy and resource saving. The architecture of old is not an ideal Platonic production just waiting to be rediscovered and re-evaluated. Hygienism did not go out with the urban utopias of the last century: built works, be they newly constructed or rehabilitated, must still provide fresh air and light, improve the living conditions of their inhabitants and adapt, in Mediterranean towns even more than in many other places. Rehabilitation is a project, not a revival. Ultimately, traditional architecture has a lot to teach us. Without idealizing it, at its best it has brought an economical approach to technical situations in which our modern solutions may work, but at too high a cost. It uses local materials profitably, it ventilates houses in hot countries without the need for air-conditioning, and it implements human expertise in the face of both scarcity and wealth of resources. These indeed are lessons to be learned, not copied thoughtlessly but analysed to make the most of past experience.

So let us unashamedly make economics our central concern: making improvements at an affordable cost, with the idea of making something to last, is evidently more acceptable than constantly reconstructing, abandoning what was still useful yesterday and will continue to be, provided the right means are implemented.

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The Social and Cultural Values of Cultural Heritage in Palestine: Whose values, the practitioners or the owners?

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Suad Amiry Ph.D. in Architecture Director of Riwaq Centre for Architectural Conservation, Ramallah, Palestine (P.N.A.) Farhat Muhawi architect Associate architect at Arco Office, Ramallah, Palestine (P.N.A.)

Introduction: Cultural Heritage in Palestine is rich and diverse. In addition to its numerous monumental religious sites such as the Dome of the Rock, the Nativity Church, the Holy Sepulchre, and the Ibrahimi Mosque, Palestine has a number of valuable historic Monuments which are of different historic periods and architectural styles; of most important are 13th century Mamluk public buildings in Jerusalem. In addition Palestine posses’ historic city centres such as the old city of Jerusalem, Hebron, Nablus and Bethlehem. Further, the Palestinian villages with their organically beautiful peasant architecture add to the variety and richness of this heritage. The desert monasteries located in the eastern slopes illustrate another typology, as does “throne village architecture”, which refers to the feudal palaces in the eighteenth and nineteenth century rural Palestine. The caravanserais along historic trade routes, in addition to the dispersed holy shrines (maqamat), and the beautifully constructed dry stone farm houses, within the typically terraced hills of Palestine also illustrate the variety and richness of a cultural heritage which the Palestinian people have been entrusted with for the World Community at large. The Old City of Jerusalem was included in the UNESCO’s World Heritage List in 1981. A tentative list of twenty Cultural and Natural Heritage Sites of Outstanding Universal Value in Palestine1 was also prepared in June 2005 by the Ministry of Tourism and Antiquities through a consultative process that involved Palestinian experts from several cultural heritage institutions. Like most other third world countries, the protection of cultural heritage in Palestine faces a number of obstacles and challenges which makes its protection (let alone its development), an extremely difficult task. Such difficulties vary from the lack of proper legal frame works, lack of skilled human resources in most areas of cultural heritage (conservation, management, documentation, planning etc) and the absence of a national

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Mazra'a Alquiblia [Rula Halawani, RPA]

policy for protection, and hence the lack of budgets. The scarcity of land in Areas A and B2 resulted from the Oslo Agreement in 1993; the lack of efficient cultural heritage authority, in addition to the chaotic and unplanned urban sprawl which took place in the last ten years, left the cultural heritage in Palestine under continues threat of destruction. Moreover, cultural heritage has not yet been put as a priority on the national agenda, and is still seen as a liability rather than an economic and social development factor.

The Social and Cultural Values: Whose Values, Practitioners or Owners? This article tries to shed some light on the issue of social and cultural (and other) values of cultural heritage in the case of Palestine. It tries to discuss the reasons for the immense


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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation The Social and Cultural Values of Cultural Heritage in Palestine: Whose values, the practitioners or the owners?

Al Nabi Mousa on way to Jericho [John Torday, Riwaq Photo Archive (RPA)]

Artas valley [John Torday, RPA]

Dead Sea-Jericho [John Torday, RPA]

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discrepancy which exists between cultural heritage experts and practitioners "agreed upon" aesthetic, historic, scientific, social values (that of international conventions and charters such as the UNESO Convention of 1972 and the Burra Charter), and that of the laymen's and owners of the cultural heritage properties. Is that gap in developing countries, such as Palestine, much more than that in developed western countries? And if yes why? And what are the pre-requisites for bridging that gap? If one assumes that recognizing the value of cultural heritage is the first pre-condition or pre-requisite to its protection, then the question becomes which values and for whom? It is true that cultural heritage (for us specialists and practitioners) should be protected for its own merits as it embodies a nations/community/a group of peoples collective memory, history, and forms an important component of its identity. However this does not seem to be of relevance even for people like the Palestinians, whose cultural heritage has been the main target of eradication and destruction in on going political conflict with the state of Israel. As a result of the creation of the state of Israel in 1947, as well as Israel's continued 38 year policy of grapping more land from the West Bank, the Palestinians have lost a great deal of their cultural heritage: the eradication of hundreds of villages, the demolition of many historic quarters. Most important has been the systematic Judiazation (manifested in building more settlements) of the land, which results in the dramatic change of character of land, landscape and human settlements; from having an Arab character to that of westernized character3. The relevant and challenging question is: has such dramatic losses made the Palestinians value the remaining parts of their cultural heritage more? The authors of this paper argue that the sad and surprising answer is NO. This is of course manifested in the every day alarming destruction that one sees in the historic centers of all Palestinian cities and villages. This is also manifested in the Muqata' the Headquarters of late President Arafat in Ramallah which witnessed historic events for a historic figure such as Arafat. How come this has been easily demolished or "cleaned up" no traces has been left of that collective memory? The same is true in Egypt where the house of the most loved singer in the history of the Arab world; that is the Villa of Um Kulthum, had been demolished in Cairo with very little attention or consideration to protect it. Such sad examples made us as practitioners think: under what circumstances/conditions or what does it take for people to value their cultural heritage? How can we make people believe in the values of cultural heritage when basic every day life need of cultural heritage owners are not meet under Israeli military occupation?

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Since a lengthy discussion is beyond the scope and length of this paper the authors of this paper chose to ask the relevant questions without necessarily answering them. This brings us to the more complex issue or concept of the private versus the public: How does the concept of the private space/ownership and the public space/public ownership play into this? How does the "sacredness" of the private property relate to the public interest and values? And hence the issue of whose heritage it is? How does the concept of citizenship or lack of it

play a role in the protection? What is the role of governments in protecting the right of the public? And what is exactly the role of governments central and local? And particularly in the case of Palestine, how does the absence of middle class play a positive or negative role in this matter (issues of ramification)? Finally we would like to say that only through the economic value of cultural heritage do people in third world countries start valuing their architectural heritage, i.e. when cultural heritage becomes an economic source of income.

1 For more information see: Inventory of Cultural and Natural Heritage Sites of Potential Outstanding Universal Value in Palestine, June 2005. The Palestinian National Authority, Ministry of Tourism and Antiquities, Department of Antiquities and Cultural Heritage. 2 Areas A: Area which was under the security and administrative control of Palestinian National Authority (PNA) after Oslo peace process. Areas B: only administrative control o PNA. 3 For more information on this subject see: Benvenisti, Meron. Sacred Landscape: the Buried History of Holy Land since 1948. Berkeley: University of California Press, 2000.

Beit Wazan [Mia Grondahl, RPA]

Nablus [Rula Halawani, RPA]

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Architectural heritage: adaptation, use and maintenance

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Abdelaziz Badjadja Architect Professor in Architecture at the University of Constantine, Algeria

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These days, old architectural heritage excites a feeling of indifference or even hostility in most people, since buildings constructed in the past no longer respond to present-day needs or “architectural” tastes. Just because it is old, rather than falling into disuse a building should recover its interest and awaken an awareness of its cognitive and emotional value; the need to ensure the conservation of cultural heritage has to be widely accepted and form part of the sensibility of all social spheres. However, an interest in safeguarding this precious threatened heritage by no means conceals a tendency to neglect the needs of the present day. On the contrary, it is the consequence of changes in the mentality, inclinations and aspirations of contemporary society. The conservation of old buildings has to form part of a wider campaign that seeks to protect and improve humankind’s living conditions.

Inappropriate use Due to their rapid development and the growing density of their populations, cities have undergone a far-reaching alteration of both their figurative and building structure. Predominantly residential constructions are experiencing major changes: ground floors and mezzanines are, for the most part, converted for use to commercial or artisan purposes. These inappropriate uses can be attributed to the socioeconomic conditions of their inhabitants. Families have small incomes and many young people are unemployed while aspiring to a certain social status, as the opening up of the market offers interesting opportunities for the demands and needs of a growing population. The resulting modifications, often without the intervention of a professional, are frequently detrimental to the building. When it proves to be necessary, the choice of a new function is an infinitely subtler process because it raises a number of underlying issues: how to conserve the architectural character of a building after a change of function? As a result, work carried out to change a building’s function (from residential to commercial), often without the intervention of an architect, actually damages the building on different levels. Alteration of the figurative structure and urban profile The architectural character of the building is erased in the face of the additions required by the new function. Building work masks

Zaouya Sidi Abderrahmane, Constantine.

or distorts its arrangement and decoration. This attitude of modernization according to present-day tastes, comprising a complete upheaval with no consideration for the character of the construction, causes major and sometimes irremediable damage: Modification of openings in the façade Suppression of mouldings (bands, cornices, parapets, niches, etc.) A new distribution that does not take into account the layout of the façades The use of concrete as a replacement material Renovation of the lower part of the façade involving a rendering that does not allow predominantly stone walls to breathe remplacement des menuiseries anciennes par des modernes Use of ostentatious artificial lighting (neon, spots) Excessive use of modern materials (floor slabs, marble, miscellaneous wall coverings, aluminium display cases and racks, etc.) characterized by a polychromy and texture that present a considerable contrast with traditional materials, shrouded in a patina that gives them a beauty that represents the age-old expertise of humankind.

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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation Architectural heritage: adaptation, use and maintenance

Destabilization of the bearing structure When developing a site, a number of parameters must be addressed in order to ensure optimum use. Work generally involves: Extending surface areas iIntroducing new installations Increasing ceiling heights Lighting and ventilation of interior volumes Treatment of spaces Renewing old drainage networks. If carried out without the intervention of a professional, these operations often involve aberrant solutions that compromise the stability of the building:

Constantine.

Large openings (display cases, windows, etc.) are made in vertical and/or horizontal bearing elements (openings to build a stairway, trap door leading upstairs, etc.) Structural floors are overloaded (storeroom, miscellaneous apparatus, etc.) Rather than being resolved, existing defects are ignored and concealed, for example using wall coverings (tiles, wallpaper) to hide unsightly manifestations of pathologies such as blistering, black damp stains, etc.

Lack of maintenance The occupants of housing in old city centres are largely tenants and often have ambivalent relations with the property owners. Their cultural (little or no education) and socio-economic status (social class of rural origin with its specific form of appropriation of space, characteristically large, low-income families) are determinant factors in their negative attitude to their built environment, which is old, run-down and cramped. Their living environment, often limited to a single room with a high rate of occupation, receives little maintenance or is completely neglected. This behaviour can be attributed to: Ignorance and negligence; the occupants do not even see the defects as serious progressive pathologies and have no idea of the extent of subsequent damage Lack of resources; the work required to correct these defects involves sums of money that the occupant does not have A deliberate attitude in the hope of being allocated alternative housing As tenants, they feel no concern for the state of the property. The owner may be absent, unable to afford work or involved in litigation with the co-owners or neighbours (the existence of

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Dar Meharsi, Constantine.

Courtyard in the Medina. Constantine (Algeria).


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shared elements in constructions makes it difficult to define the party responsible for a given intervention).

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The result of this state of affairs is an almost total absence of responsibility for the building, which takes the form of lack of maintenance and inappropriate use. Building maintenance must not be neglected, because it will prevent defects that are more serious; a building is subject unconditionally to a process of ageing by multiple exterior agents that undermine it and limit its continuity in time. It is also important to take preventive action that may prevent subsequent defects: revision of roofs and downpipes, protection of masonry by maintaining renderings and joints, treatment of wood, etc. Inappropriate or improper use can also be the cause of serious progressive pathologies, such as excessive weight on structural floors (water deposits, storage of objects in a small space), excessive stress of certain elements of the structure (cluttering of ribs and ties), and unsuitable cleaning methods (repeated swilling that in the long term produces rotten timber elements, particularly windowsills). In most cases, when these issues are addressed, the defects are treated superficially, attacking the symptoms rather than the causes: filling cracks, removing and partial replastering crumbling renders, laying boards over a sagging structural floor to restore its horizontality, and so on. For the inhabitants of a town or city, a well-conserved building or architectural complex is a lesson in housekeeping, community spirit and cultural requirements, the symbol of a community. It is this single element, which must not be a museum or a foreign body, which informs the whole atmosphere of the city.

Kasbah, Constantine.

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Bioclimatic values in the rehabilitation of Traditional Mediterranean Architecture

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Xavier Casanovas Technical architect Director of the RehabiMed European project (Col·legi d’Aparelladors i Arquitectes Tècnics de Barcelona) and lecturer in the Department of Architectural Technology II, School of Building Construction of Barcelona (Technical University of Catalonia), Spain Ramon Graus Architect Lecturer in the Department of History and Theory of Architecture, School of Building Construction of Barcelona (Technical University of Catalonia), Spain

The traditional architecture we find in the Mediterranean basin continues to be of an extraordinary richness. It is the product and the reflection of societies accustomed to intense interchange, and it has taken form slowly precisely thanks to these interchanges. It is however important to point out immediately that it is a disappearing architectural form, because it was produced on the basis of a logic that we call pre-industrial, when things happened slowly, when the shapes of architecture were distilled with the passing generations and when know-how was handed down from father to son in families of builders (known as master builders, maalem in Arabic). The societies living in the Mediterranean have changed radically since the arrival of the phenomenon of industrialization, now refined for the umpteenth time in the form of globalization. The communities that built and dwelt in this architecture have disappeared or are breaking down, and other logics are now at play (migration, second homes, creation of ghettos, gentrification, fall in property value leading to replacement by new buildings, etc.).1 Sometimes, our romantic, melancholic view prevents our seeing that its inhabitants have to be able to transform it in order to adapt it to the needs and aspirations of the present day. In this article we will attempt to present the richness in bioclimatic terms of this architecture and to reflect on the possibilities of rehabilitating it to make the most of its huge potential, with all the respect it deserves. The house in a place in the Mediterranean Having ventured to speak of the concept of Mediterranean Traditional Architecture2, we must straightaway stress its wide diversity. In climatic terms, the Mediterranean is characterized by a temperate climate that changes rapidly as we move south, becoming hot and dry, or becomes quickly colder as we move inland and to higher ground in the nearby mountains3. Its traditional architecture responds to a balance between its inhabitants’ various needs (use of the building, subsistence

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Covered passages in Cairo (Egypt)

economy), available building materials and, of course, protection from the natural environment. Firstly, it is important to consider that traditional architecture takes radical and ingenious forms when environmental conditions are very severe. For example, the wealthy houses in Cairo, Egypt, developed the malqaf, a kind of skylight, borrowed from hot areas of Persia, to harness the breeze from the Nile and draw it through the main rooms in the house for ventilation. Then in various hot, dry places in the Mediterranean with rather cold night-time temperatures (Matmata in Tunisia, Cappadocia in Turkey, Guadix


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The malqaf of El Set Wasela (Egypt) and a diagram showing the ventilation system

and Paterna in the Iberian Peninsula, Matera in Italy), cave dwellings were built, homes dug into ground that was easy to excavate, to make the most of the thermal inertia of the site. In colder mountain climes, the kitchen (also the centre of energy) is placed at the centre of the house with walls that also harness thermal inertia, though in this case to prevent the heat leaving too

quickly. In most Mediterranean countries, the houses tended to stand two or three storeys high, with livestock kept in a semibasement ground floor to harness their body heat in the winter (in summer they were sent to graze in the mountains and the interior was cool) and the harvest was dried in the well aired attic, providing excellent insulation.

Underground dwellings in Matmata (Tunisia)

Underground dwellings in Paterna (Spain)

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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation Bioclimatic values in the rehabilitation of Traditional Mediterranean Architecture

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Detached house in the Pyrenean foothills in Guixers (Spain), fireplace and loft

However, when the climate is more temperate and there is an intense cultural residue, the repetition of a specific model of architecture is more associated with the culture of a society than with the climate. Consider the example of the courtyard house. In desert climates, a high, narrow courtyard (for example in the ksar of Tamnougalt in the southern Moroccan Atlas), 4collects the cold

night air and keeps the space cool for much of the day, providing ventilation but not allowing sunlight or sand to enter. In more benign climates, however, the courtyard is larger but does not have a clear bioclimatic function, since it is closely connected to the culture of privacy of an inward-looking house that characterizes Islamic culture.

Courtyard of a kasbah in the Tamnougalt ksar (Morocco)

Courtyard of Dar Ben Abdallah in Tunis (Tunisia)

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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation Bioclimatic values in the rehabilitation of Traditional Mediterranean Architecture

Then we have to be wary of the word “tradition”. Since when and in relation to what is a building traditional? For example, throughout the Mediterranean, the lines between traditional and cultured architecture are ambiguous and blurred. The “traditional” Lebanese house, the house around a central hallway or the three-arch house5, is very similar in structure and functioning to the house on the terra firma of Venice, the Catalan masia and the typical Ottoman house with its central sofa. From all of the above we can deduce that most traditional Mediterranean architecture is situated in areas with a temperate climate. But the conditioning factors represented by the temperate climate, to quote Rafael Serra, “are merely those of other types of climates, less harsh but with the essential characteristic that they may all be present at once. These are the ‘problem of the cold’ in the winter, which may be dry or damp, a distinction that is not important in more extreme climes though it is in these. The ‘problem of the heat’ in the summer (dry or humid), almost as intense as in other climates, despite lasting relatively few days. Finally, the ‘problem of changing weather’ in intermediate periods, when there may be extreme cold or heat for short periods of time.”6 The art of choosing a good site and the intermediate spaces It will come as no news to anyone that traditional architecture has its own particular wisdom when it comes to choosing a site in the territory. This is its starting point. A form of architecture that is poorly positioned in relation to the sun, which is the great dictator, will rarely have bioclimatic virtues. But a good siting also means concealing from or exploiting the wind, orienting each of the rooms according to its daytime or night-time use, and so on. Here we have to insist on the idea expounded above: the more severe a climate, the more radical the solutions. Here we can give examples, too: a ksar is a fortified village in the valleys of the southern Moroccan Atlas Mountains that protects itself from heat, cold and sand by crowding the houses together and seeking to reduce the number of façades that exchange heat with the exterior. Conversely, a farmhouse in the Pyrenean foothills is a building that can stand open to the four winds on a south-facing slope and positions its front door in the façade that is protected from the cold wind. By this token, villages on mountainsides have always constructed their streets to follow contour lines with the ground floor of the building in front dug into the ground to avoid blocking the sun from the building behind, and its front door on the street above. This type of arrangement usually guarantees cross ventilation. This is a concept developed by the Modern Movement, but one that had long been current in traditional Mediterranean architecture. One good example is the Lebanese custom of placing small sandbags at all the doors to keep them open and allow ventilation between the front and the rear of the building.

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The Tamnougalt Ksar (Morocco)

Percentage of openings in the façades of a detached house in the Pyrenean foothills in Guixers (Spain); south, east, north and west façades

Houses terraced on a natural slope in Berat (Albania)

The sandbag used in Lebanese tradition to prop doors open, creating cross ventilation of the rooms

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Foyer of a house in Lefkara (Cyprus)

Roof of plant matter with jasmine in Jesús Maria (Spain)

Gallery of a house in Bda (Syria)

The vegetation in the Riad Berebere in Marrakech (Morocco)

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In addition, in a temperate climate such as ours, traditional architecture seeks protection, pleasant views and sea breezes by means of what we might refer to as intermediate spaces between the interior and the exterior, which generate pleasant microclimates according to the period of the year and time of day. The diversity of these spaces is what makes traditional Mediterranean architecture so singular. A covered street or a porch at the entrance to a house is the first space of this kind. Of solid construction or comprising canes and plants, such as vines or jasmine, it welcomes the visitor and protects the inhabitants when they sit at the front door to wile away the time or mend a tool, etc. This is a key element that in climatic terms leads to the life in the street and the sociability that characterize Mediterranean places. A similar space, and one that is common to the architecture throughout the Mediterranean, is the gallery, a raised porched space, usually with columns that support arches, which serves as a hallway to a series of rooms but is also large enough to sit out or dry the harvest in. In Catalonia, it is also known as solana (a sunny outdoor space), which is the same as the Arabic riwaq or the Greek iliakos. A particular example from the Near East is the iwan, originating in Persia. This is practically a room with one of its sides missing, a covered but open-air space for a variety of functions, serving as a hallway for the rooms that open onto it. The simplest structure is two rooms with a central iwan, but the layout may be further complicated by juxtapositions, courtyards, etc., producing rather complex compositions. A very simple but effective element is the eave, a projection of the roof that provides shade in summer and allows winter sunlight in as a result of the varying trajectory of the sun, which is lower at this time of year. A similar but more sophisticated phase is the tribuna (bow window), a small room that can be closed off from the other rooms in the house and that looks out onto the exterior through a glazed facing. This is a place to spend the winter hours that harnesses the greenhouse effect for heating and transfers some of the heat to adjacent rooms. The tribunes in Barcelona’s Eixample are an obvious example, though it is closely associated with tradition and can be found everywhere, being particularly abundant in the architecture of Turkey. This brings us to the courtyard, the paradigm example of the “inside-outside” intermediate spaces of traditional Mediterranean architecture. Its bioclimatic behaviour and the strong cultural links that have guaranteed its continuance are outlined above. It only remains to add that in every region the proportions of its floor plan and section offer the most suitable response to the climate of each place. The house with peristyle of Hellenistic tradition was followed by a series of adaptations of the courtyard: the Roman domus, the courtyards of the Catalan Gothic townhouses and, of course, the appropriation of the tradition of the courtyard (west


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Eaves of a house in Gjirokastra (Albania)

The buildings of Ait Larbi in the Dades Valley merge with the surrounding landscape (Morocco)

ed-dar, the centre of the house, in Arabic) by Islamic culture and the radicalization of its use, turning it inwards. It was in Islamic culture that the courtyard found its ultimate application, together with vegetation and water. Water was introduced in the form of a fountain or small pool, thereby creating a microclimate with a degree of moisture. This environmental improvement also introduced vegetation, as in the example of the riad of Marrakech.

comfortable interior spaces. In this way, the surfaces exposed to the sun’s rays absorbed the heat, but since thick stone or earth walls transmitted it slowly, the interiors remained cool during the day. The walls then stored the heat and transferred it to the inside, maintaining a pleasant temperature throughout the night. This phenomenon, explained here in relation to the walls, is also applicable to the traditional flat roof. The terrace was a flat ceiling of timber beams covered by a hand’s span of earth that provided a roof and also, depending on the time of year, another room (bedroom, kitchen, drying shed, threshing ground, etc.). Flat roofs of this kind are found in the North African Atlas, the mountains of Lebanon, the Alpujarras of Andalusia and, formerly, across a whole swathe of the Pyrenees7 and the Alpes-Maritimes. Another important factor was the breathability of these walls— that is, their capacity to absorb moisture and dry out, and to balance exterior and interior humidity. This was possible thanks to a culture of using breathable coatings such as plaster, earth or lime mortar renderings, and whitewashes.

Local materials, breathability and thermal inertia The world of pre-industrial construction was characterized by lowcost labour offset by the great expense of transporting construction materials to the site. It was therefore natural to try to use the materials closest at hand to the site or those that were easiest to use. This led to earth, local stone, lime mortar or plaster and wood becoming omnipresent materials in construction. Some materials from the agricultural world, such as straw, were used as good insulation in many different solutions. It is interesting to see how this subsistence economy configured the landscape of a territory. The tones of the earth and stone used to build houses blended in with the colours of the surrounding hills to form an inseparable part of the landscape. At the same time, what was usually a solid earth or stone construction (rammed earth, adobe, rubblework, etc.) was characterized by using its thermal inertia to guarantee

Light filters Finally, traditional Mediterranean architecture is characterized by an infinite wealth of solutions to provide filters on the openings in buildings (doors, windows, balconies), thereby responding to the variations in our temperate climate with the threefold aim of providing thermal insulation, shade and ventilation.

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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation Bioclimatic values in the rehabilitation of Traditional Mediterranean Architecture

Gallery with a whole range of filters in Sidi Bou Said (Tunisia)

Solar Protection with curtains in the Kasbah of Algiers (Algeria)

Making a hole in a façade has always been a delicate task. There was a temptation to make a large hole, but caution advised making it smaller. We have to remember that the use of glass (to provide insulation, let light in and allow visibility) was a luxury for those societies and a great deal of ingenuity was needed to make as large a window as possible without creating an imbalance in heat gain. Whereas initially these openings had just a wooden shutter with a spyhole (a smaller opening with a small opening shutter), they were gradually succeeded by larger openings protected by waxed paper, and it was only considerably later that glass was incorporated. This is a good example of how traditional architecture is not immutable; it constantly changes as it absorbs, we might say, "modernizations". Adaptability is certainly one of the foremost values of this type of architecture, as it has demonstrated over the years. It has taken the incorporation of technologies that are remote from the human scale to bring about a breakaway that traditional Mediterranean architecture continues to resist today as a more sustainable and environmentally friendly alternative. There is a whole range of solutions. For example, in Catalonia, a window opening could comprise the frame and the operable sash of the window, protected on the outside by a paravent, or outer shutter, another shutter in the interior behind the glass to

graduate the light and, finally, net curtains or drapes tamed the sun and provided privacy. The Mediterranean is full of different types of blinds: adjustable elements to control the intensity of indoor light. This is the case of the simple cord blind which, with its various positions (completely up or down, half up/down or resting on the balcony railing) helps to control the indoor temperature. It also applies to the more complex Venetian (or Majorcan, depending on the place) blind, a kind of lattice of adjustable slats on a frame. In this case, the light and air let into a room can be precisely adjusted: completely open, completely closed and the endless variations between, as shown by the images that accompany this article (directing the light to the ceiling or to the floor, allowing someone inside to look out, etc.). Islamic societies combine the climatic need to filter the light of a blazing sun and the culture of the veil—seeing without being seen. Here the mashrabiyyaa comes to the fore. This carved wooden lattice fills the window, allowing in air and very filtered light while allowing those on the inside to look out. Much of the opening is fixed but it also has movable frames, also made of wooden trellis.

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Conscientious rehabilitation Rather than incorporating bioclimatic gadgets, the rehabilitation of a building has to bring a sensitive approach to the traditional


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Recovery of a parapet to allow ventilation on a terrace roof in Hebron (Palestine)

Exterior and interior views of the mashrebeeyeh of El Set Wasela (Egypt)

elements described here. Conscientious rehabilitation work should not prejudice or ignore them. However, we also have to accept that these passive systems of environmental control do have their limits. In themselves, they guarantee reasonable comfort levels, but if we want a constant temperature of 20ºC and relatively humidity of 50% when the outside values are 35ºC and 30%, only an active system will do the trick. However, this is nothing new: to combat the cold in a traditional house, the inhabitants light a fire, which is merely another artificial system for producing heat. A rehabilitation project has to weigh up the needs of a programme (the client’s requirements), the values of the architecture in question (cultural, architectural and also bioclimatic) and knowledge of the current state of the building. The RehabiMed method insists on the need for knowledge prior to the intervention—that is, it is necessary to make a careful diagnosis of the building (including the thermal balance) before undertaking rehabilitation. It is, then, necessary to understand how the building functions, and to rehabilitate and modernize it on this basis. Having read this article, readers will deduce that we favour a form of rehabilitation which, on the basis of traditional construction and ambient control mechanisms, seeks to adapt the conditions of the building to present-day needs; but also brings a sensitive approach to thermal inertia as opposed to insulation without

criteria (for example, in a thick-walled building the north-facing façade can be hyper-insulated, and less or no insulation used on the faces that receive more sunlight to exploit their thermal inertia), maintains the breathability of the walls (for example, using lime renderings and breathable whitewashes or silicate paints rather than the cement renderings and vinyl paints that break with this hygrothermal balance), respects intermediate places (for example, avoiding the speculative appropriation of these spaces by metal window/door frames) and conserves traditional solar filters (for example, avoiding the systematic replacement of frames by simplistic aluminium or PVC solutions). Only after integrating these parameters is it appropriate to consider the real need to introduce an active atmospheric control system (be it heating or air conditioning). Once the building has been rehabilitated, it is occupied by the people who are to live in it. We began this article by saying that the society that produced this architecture has disappeared so the new user might not know how to "work" the building. We think that new users have to be told how to use it by means of a short instruction and maintenance manual presented at the end of rehabilitation work. The “Majorcan” blind would therefore have instructions for use to optimize its functioning, as though it were a domestic appliance. Although, for example, it requires an effort to maintain a woodenframed window rather than install the low-maintenance solutions

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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation Bioclimatic values in the rehabilitation of Traditional Mediterranean Architecture

offered by the market or opt for the convenience of a standard aluminium blind with remote control, we think that it is these aspects that demonstrate a conscientious approach to the rehabilitation of traditional Mediterranean architecture.

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1 CASANOVAS, Xavier (dir.): Rehabilitating Traditional Mediterranean Architecture. Marseilles, 23, 24 and 25 September 2005, Col·legi d'Aparelladors i Arquitectes Tècnics de Barcelona. Barcelona, 2005. 2 NOURISSIER, Gilles; REGUANT, Joan; CASANOVAS, Xavier; GRAZ, Christophe: Traditional Mediterranean Architecture. École d'Avignon, Col·legi d'Aparelladors i Arquitectes Tècnics de Barcelona, Ecole des arts et métiers traditionnels de Tétouan. Barcelona, 2002. 3 FOLCH, Ramon (dir.): Mediterrània: territori i paisatge. Atles Ambiental de la Mediterrània. Institut Català de la Mediterrània, Institut Cartogràfic de Catalunya, Estudi Ramon Folch. Barcelona, 1999. 4 BADIA, Jordi; CUSIDÓ, Oriol; GRAUS, Ramon; MANRIQUE, Emili; NOY, Martí; VILLAVERDE, Montserrat: [Spanish-French version, Marruecos presahariano. Hábitat y patrimonio - Le Maroc présaharien. Habitat et patrimoine. UNESCO, Col·legi d'Aparelladors i Arquitectes Tècnics de Barcelona. Barcelona, 1998. Translated by Marinette Luria]. 5 HUSSEINI, Frédéric; NOURISSIER, Gilles; CASANOVAS, Xavier (dirs.): Manuel pour l'entretien et la réhabilitation de l'Architecture Traditionnelle Libanaise. École d'Avignon, Corpus Levant Project. Avignon, 2004. 6 SERRA FLORENSA, Rafael: Les energies a l’arquitectura. Principis del control ambiental arquitectònic (1993). Edicions UPC (2nd edition). Barcelona, 1995, pp. 200-219. 7 CASANOVAS, Xavier: "I tetti piani nel Pirineo catalano", CATALDI, Giancarlo (Dir.): Attualità del primitivo e del tradizionale in architettura. Atti del Convegno Internazionale 'Le ragione dell'abitare', Prato, 8-9 January 1988. Alinea Editrice. Florence, 1989. pp. 135-141.

The multiple possibilities of wooden blinds with adjustable slats in Barcelona’s Eixample district (Spain)

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Traditional architecture and climate in Tunisia

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Radhia Ben M’barek Architect Chief architect and specialist in heritage architecture 1

Over the centuries, our ancestors acquired a certain knowhow in the field of construction, based on an intuitive knowledge of their environment and climate. The construction techniques and materials used were chosen with great care in order to adapt their dwellings to the climate. This concern is all the more noticeable in areas with a hot climate, such as the south of Tunisia. Cave architecture is a fitting response to the rather harsh climatic constraints of some southern regions. This type of habitat comprises a series of dwellings in the ground, using natural cavities or specially dug-out holes. The principle condition of this type of dwelling is the presence of dampfree soft ground. This type of dwelling is an excellent response to hot climates. The underground dwelling avoids the intense heat of summer and the icy cold of winter thanks to the increase in thermal inertia, due to the mass of the ground. Furthermore, the notion of exterior façade is absent, which considerably limits heat gain in summer and loss of calories in winter. Thus the daily range of temperature is totally irrelevant. The yearly range of exterior temperatures is the only magnitude that influences the interior. The thermal properties of this habitat vary according to: The nature of the ground, which may be more or less inert or insulating The thickness of the walls Exposure to the sun.

Tunis, Tunisia

In the south of Tunisia, there are basically two different types of cave dwelling according to the nature of the ground. The first is in the region of Matmata and the second in Chénini.

dwellings around a courtyard an attractive proposition: in addition to the ground’s thermal inertia, the amount of façade exposed to the sun is kept to a minimum, as the courtyard increases the amount of shade. It also makes it possible to exploit the earth’s radiation (cooling the surfaces of the courtyard). The cool air at the bottom of the courtyard noticeably decreases the ambient air temperature.

The cave dwelling in Matmata In Matmata, the traditionally built habitat comprises dwellings constructed around a fairly deep central shaft, which may be as much as 10 metres deep. The rooms are dug out around this courtyard, sometimes on two levels, and organized in complex apartments made up of bedrooms, storage space, stables, etc. Entry to this central courtyard is via a sloping tunnel that emerges to the exterior some tens of metres away. Some are equipped with a water deposit, dug beneath the courtyard, to collect rainwater. The aridity of the climate makes the construction of underground

Cave dwellings in Chénini In Chénini, another type of cave home is built on a hillside, dug into the earth through strata of hard rock that forms the roof. These dwellings have fewer advantages than those in Matmata, though in relative terms they are more efficient, bearing in mind the impossibility of digging vertically due to the presence of rocky ground. Cave dwellings illustrate the role of the thermal inertia of the ground in establishing interior ambiances and prove to be the dwelling best suited to hot, relatively dry climates with a large annual temperature range.

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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation Traditional architecture and climate in Tunisia

For these cave dwellers, calculations show that the phase shift of the annual thermal wave was in the region of six months. However, whichever form of cave architecture we are dealing with, various other factors and elements intervene in the creation of bioclimatic architecture. Different possibilities were adopted by our ancestors with a view to obtaining maximum comfort and responding to the demands of the occupants of spaces in hot regions, in order to produce a comfortable form of architecture. By way of example, the vernacular architecture of Djerba is based on isolated dwellings with a central courtyard and thick walls, set amid vegetation. This construction is called el menzel. Great use is made of vaulted and domed roofs. The traditional Djerba house is characterized by the presence of one or more rooms raised above the other spaces, situated at the corners of the dwelling. This room, or ghorfa, has a small opening near the top of the space that allows natural ventilation. In the case of the vernacular architecture of Tozeur, palm groves provide a filter to the hot air and the sun’s rays. The building is situated on the north side of the palm grove, protected from the sand-bearing south winds. The characteristic façades of this region of Tunisia are built of solid brick in such a way as to create projections that offer a variety of shaded areas. The exterior spaces of the old towns are also treated with a view to obtaining a degree of climatic comfort. The sabat was created for this purpose, forming shaded areas and reducing the incidence of solar radiation on the house façades. This concern is also found inside the house, where the solution of building around a courtyard means that there is always shade, with a minimum of solar radiation on the various façades of the construction in the course of the day.

In thermal terms, the courtyard is like a cooling shaft, since the cool air cannot escape and cools the rooms that open onto it. The facings of the courtyard absorb the hot air from the interior spaces and the walls that receive the sun, then emit it and cool down. This coolness is then transmitted to the interior of the spaces. The courtyard is, then, a regulating element that benefits the entire dwelling. Finally, we can say that our ancestors had to take into account a variety of factors and elements to achieve a form of architecture that responded to their need for climatic comfort, including:

Matmata, Tunisia

Matmata, Tunisia

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The form of the roofs In summer, the sun shines mainly on the roof. The east and west walls receive half the radiation of the roof. This is why the form of the roofs is important to comfort inside the dwelling. Due to their form, vaults and domes are less exposed to the sun’s rays and the wind. The use of this type of roof therefore helps to reduce the impact of the sun’s rays at roof level and then in the interior space itself. The openings The minimization of openings to the exterior is one point of consideration. Some façades have no more than an entrance door with an opening above it (air vent). This design and organization of the openings ensures good ventilation, giving the home interior comfort at all times. The high position of openings facilitates the exit of hot air. As a result, cool air comes in through the doors and out through openings high up, generating a natural ventilation system.


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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation Traditional architecture and climate in Tunisia

Building materials

I. Knowledge

Stone: for the construction of walls and vaults Gypsum: used as a binding agent Lime: generally used for renderings.

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These three principal materials in traditional construction offer efficient resistance to heat conduction, allowing the creation of a cool interior. The mass of the envelope In traditional construction, the thickness of the walls varies between 50 and 70 cm, and may be as much as a metre, ensuring good insulation and slow heat transmission. Furthermore, the compactness of the volumes helped to limit the effects of heat; building a dwelling (and other constructions) against its neighbours provides extra protection from the heat by minimizing exposed surfaces. Colour The use of light-coloured cladding for the roof, floor and walls ensures minimum absorption of the sun’s rays. Whitewashing or painting them a light colour (particularly white) helps insulation by reflecting solar radiation.

Kairouan, Tunisia

Tunis, Tunisia

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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation

A tool to develop the use of solar energy in Mediterranean basin: the European Solar Radiation Atlas (ESRA).

École des Mines de Paris, France

This atlas offers a unique instrument dedicated to the knowledge and exploitation of the solar resources in the Mediterranean basin. It is a powerful tool for architects, engineers, meteorologists, agronomists, local authorities, tourism professionals, as well as researchers and students. It covers the period 1981-1990. It offers fundamental knowledge on the solar radiation available at ground level, which is of primary importance for both the life and the climate (including the ocean) since it is the primary source of energy on Earth by far. The Atlas co-ordinate by K. Scharmer and J. Greif, published by Les Presses de l'Ecole des Mines as The European Solar Radiation Atlas - vol. 1: Fundamental and maps, describes the course of the Sun across the sky as it varieties throughout the year and with the geographical location. The interactions of the solar radiation with the atmosphere and its components (haze, turbidity, clouds, etc.), and the separation of the radiation into the direct and diffuse parts are discussed. The importance of the solar radiation in various domains is presented, with an emphasis on solar engineering, where solar energy is used to provide electricity in photovoltaics systems, to supply hot water or heat houses. Ground radiation measurement techniques and instruments are described. Satellite images are also used. They are combined with ground measurements to provide a synoptic view of the distribution of the solar radiation over Europe. The structure of the database and its main applications are described. Here, we present 4 of the 26 coloured maps (ten years average 1981-90) that describe the solar radiation and its direct and diffuse parts. They also detail the changes with time. The value of the atlas can be usefully extended by using it in conjunction with the complementary volume and CD-ROM called The European Solar Radiation Atlas - vol. 2: database and exploitation software, also published by Les Presses de l'Ecole des Mines. The database offers spatial (every 10 km approximately) and temporal knowledge for different time scales (from climatological means - more than 700 stations - to hourly values 7 stations -) on the solar resources: irradiation (global and its components), sunshine duration, as well as air temperatures, precipitation, water vapour pressure, air pressure in a number of stations. The software uses the database in either a "map" or a "station" mode at user choice. Once a station been selected, the program looks for all the data available for this station. The software includes algorithms covering the following fields: solar geometry, optical properties of the atmosphere, estimation of hourly slope irradiation under cloudless skies, estimation of solar

irradiation values (going from daily to hourly values, conversion from horizontal to titled surfaces), spectral irradiance, illuminance, daily mean profiles of temperature and other statistical quantities (central moments, extremes, probability, cumulative probability and utilizability curves). Graphics can be displayed in 2 or 3 dimensions. Some applications studies on solar engineering can be performed too. This Atlas has been realised on behalf of the European Commission, by a team led by the company GET (Jülich, Germany), and comprising the Deutsche Wetterdienst (Hamburg, Germany), Armines / Ecoles des Mines de Paris et de Nantes (France), Instituto Nacional de Engenharia e Tecnologia Industrial (Lisbon, Portugal), the Technical University of Lyngby (Denmark), the World Radiation Data Centre (Saint-Petersburg, Russia), and Institut Royal de Météorologie (Brussels, Belgium), John Page (Sheffield, United Kingdom) and Robert Dogniaux (Brussels, Belgium) acting as advisors.

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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation A tool to develop the use of solar energy in Mediterranean basin: the European Solar Radiation Atlas (ESRA

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Global irradiation on horizontal plane. Monthly mean of daily sums. Tens years average. March.

Global irradiation on horizontal plane. Monthly mean of daily sums. Tens years average. June.

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Tool 1 Knowledge of traditional architecture as a basis for rehabilitation A tool to develop the use of solar energy in Mediterranean basin: the European Solar Radiation Atlas (ESRA

Global irradiation on horizontal plane. Monthly mean of daily sums. Tens years average. September.

Global irradiation on horizontal plane. Monthly mean of daily sums. Tens years average. December.

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Steps for an engineering (and non-structural) survey in pre-diagnosis phase

I. Knowledge

Yaacov Schaffer Civil Engineer, M.Sc. Ua. Israel Antiquities Authority, Israel

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The pre-diagnosis phase of an engineering survey for an existing traditional building is probably the most crucial point in the whole frame of the rehabilitation of old buildings. It is crucial because the first judgment of the building can affect the next steps, as the following states: Rehabilitation versus demolition. Liberal approach of rehabilitation versus a conservative approach The first diagnosis of physical condition of the materials and elements of the building The first possible physical-structural solutions for the building This pre-diagnosis stage should be carried out together with the first programs for the rehabilitation of the building and before any other step is implemented. In order to be able to do such a prediagnosis survey in a simple manner, rather than with a large team, there are two possibilities: an architect surveyor or an engineer surveyor. In the first option (an architect, a surveyor, a technical architect, etc., depending on the country's educational systems), he/she has to have wide knowledge on ancient technology, on the deterioration of historic materials and elements, a deep knowledge in conservation (practical skills and philosophy) and a long experience. He/she is still missing the ability to appraise the structural behavior and the condition of the old building, and a structure engineer will have to be added latter on for the structural topic. In the second option (civil building engineer, technical engineer, surveyor, etc.), he still has to have a wide knowledge in historical technology, deterioration of historic materials and elements, a deep knowledge in conservation (practical skills and philosophy) and, unlike the first option he/she has to have good experience in the structural behavior of old buildings. It is not necessary for the pre-diagnosis stage to have a special structural engineer. However, the structural engineer has to have good qualified experience in historic building systems and, more important, to limit himself to structural engineering topics. This, he should not relate to the appraisal of the physical conditions of materials, elements and conservation, conservation philosophy and conservation solutions, all topics that are not related to his skills! We remind again and again that a good engineering pre-diagnosis survey primarily relies on the objectivity of the surveyor. For this reason, it is recommended that the pre-diagnosis survey will be done by one professional and the future planning by another one!

Jaffa (IsraĂŤl)

The pre-diagnosis engineering survey is a three phases survey: The structural engineering condition and the physical engineering condition of materials and elements, and the potential solution in the frame of engineering physical condition. The steps and stages in the life of the building and its correlated conservation values. The future use of the building. Only if this wide approach is done, the pre-diagnosis engineering survey prepares the project for the next stage of a complete documentation, survey and design. Our goal is to rehabilitate the historic traditional buildings in the right, quick and economic ways. We have to take into consideration that these buildings are still a large part of the building-stock in some countries, while only a small part of the building-stock in others. Also, relatively modern buildings in one country can be considered as traditional historic buildings in another country, and we will have to approach the same topics in the same right rehabilitation approach. With this statement, having a large stock of problematic buildings, we have to create a strong and deeply rooted profession to deal with these traditional buildings. So, this pre-diagnosis engineering survey will have to include within a limited time table and a limited survey-report, the whole situation of the building and especially what has to be excluded from it. Six topics should be included in the pre-diagnosis engineering report:

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The main typical historic building technology. The main historic and existing structural engineering systems of the building. The structural engineering condition of the main building and its secondary additions. The engineering condition of materials and elements which will affect in a positive or negative way the overall engineering survey in the pre-diagnosis phase. The general physical condition of architectural elements that might be that will be affected negatively by potential structural engineering solutions. The main possible directions of structural engineering solutions.

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Some questions have to be asked and answered. Why shall one also deal in this pre-diagnosis engineering survey with the ancient technology, material conditions and architectural elements condition? There are three reasons for that: Not only is the ancient technology of the main structure responsible for the existing structural condition, but it also conditions the possible solutions from the structural, economical and conservation points of view.

Akko (IsraĂŤl)

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A good or fair condition of materials and elements could be conditioned and affected by an engineering solution, bringing a series of acts that could jeopardize the architecture and the conservation value of the building, or influence negatively on the economic part of the rehabilitation. A good or fair condition of architecture elements might be affected by a structural engineering solution, bringing together a negative influence on the architecture and the conservation value of the building itself or on the economic part of the rehabilitation. The pre-diagnosis report is especially meant for the clients that are not generally professionals in the field of engineering conservation and rehabilitation. For this reason, it has to be short, clear to the clients & non-professional staff, as well as professional and useful to the professional building staff. An example for any topic dealt with, has to be added in the form of photographs in the written report. Having all these stages and approaches in mind, the first question will be: is there such a professional person who has all the qualities described before? How many of these professionals are in each country/region/place? Can there be a separation between the prediagnosis engineering survey phase and the latter phase of documentation, survey and design planning? Should they be

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implemented by different professionals? We believe that professionals coming from the field of architecture or engineering, with a good background in the history of architecture, building technology and engineering, good specializations in cultural heritage and rehabilitation of historic buildings and a large experience in the field of survey and documentation, are able to conduce the pre-diagnosis engineering survey. More specializations in regional historic building technologies will really create the "professional surveyors of traditional buildings". Then, the addition of a structural engineering or other profession to the pre-diagnosis team will be decided, only when necessary. The separation between the pre-diagnosis surveyor and the planner should also be emphasized. First, it is true that an architect or an engineer who surveys or documents the building will collect a large knowledge for planning and designing in the latter stages. But, from our experience all over the world, we know that the possibility of being objective in the survey, when knowing that it will apply on the design and planning is very low. Today’s planning works are based on percentage rates and therefore they are conditioned by the previous surveys. Second, qualities required from surveyors and documentation persons are different from qualities of people in planning and design. So, let’s get the best from each professional. The last but not least topic is the frame of the engineering survey in its pre-diagnosis phase. Beginning with the main building technology and continuing with the structural engineering condition, the next stage will be the physical condition of materials and elements. The last chapter will be a quick report on the architectural features. Then, the summary of the report will have to include three parts:

I. Knowledge

Examples of pre-diagnosis engineering surveys: 1. The interior and exterior of a wooden building were covered with plaster. The main floors of the ground floors have a distortion, not usual to concrete floors. The back walls have rotten because of the pipes leaking from the kitchens and utilities, located in the back of the building. The first general impression was very bad. Three separate engineers were brought for the pre-diagnosis engineering survey. All three wrote reports that the building was in an irreversible bad engineering condition and that it had to be demolished. However, because of its peculiarity and a preservation approach, it was insisted that a conservation-engineer knowing these kind of technologies will inspect the building. After convincing the municipality engineer and the owner, a prediagnosis engineering survey was conduced together with the conservation-engineer, which reported that the building was in very good condition, except for the back wall. The results after the survey, planning, documentation and implementation of the rehabilitation were very positive, shorter in time and more economical in terms of budget, even when compared with the last pre-diagnosis survey! 2. Adobe buildings in a neighborhood planned for rehabilitation and revitalization faced a first quick survey (the pre-diagnosis engineering survey) by a team of engineers and architects. They immediately pointed out the nice drawings on the gypsum plaster of the interior walls and the “majolica” inside and outside the buildings. As for the engineering side, they recognized the possibility of water penetration from the street floors and other sources. Their recommendations were to

The first part of the summary will address the overall report of the physical and structural condition of the building today. The second part will present the professional engineering and structural opinions on the needs for the rehabilitation, for both the old and new uses. The third part will point-out the indirect influences of the different potential engineering solutions on the architecture, economic and conservation values of the building. To conclude, the pre-diagnosis engineering survey has a crucial influence on the future of the specific historic building and has to be done in a highly professional way. Being limited in time and results, a good pre-diagnosis engineering survey can however save a lot of energy, time and money. A bad pre-diagnosis engineering survey will influence all stages of the documentation, planning, implementation and life of the rehabilitated building. Wood building with a 1870' addition of a hip roof.

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Outside, elements giving the impression of a very bad physical condition.

Inside, elements giving the impression of a very bad physical condition.

Inside, during the rehabilitation stage, showing a good physical condition.

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immediately stop the penetration of water by filling the foundation with waterproof mortar and covering them with waterproof renders and plasters. After this stage, they recommended a large documentation and a survey, followed by a design for the rehabilitation. It was implemented on 200 buildings and after 6 months, all the interior plasters and paintings disintegrated, the adobe brick walls had large problems and all the residents had to be evacuated from the neighborhood. What had happened? The team of professionals doing the pre-diagnosis engineering survey had no idea about adobe buildings and their diagnosis was completely wrong. The foundation had to remain without mortar as a dry wall, this creating a system for evaporating the water before it reached the walls. By closing them, they created a capillarity rise of the water till the mid-height of the walls, destroying both the interior architectural features and the adobe structures. The conclusion is to avoid completely to do a pre-diagnosis engineering survey without knowing the structural historical system and the existing technology.


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Support material for the preliminary diagnosis stage

I. Knowledge

Ramon Graus architect Lecturer in the Department of History and Theory of Architecture, School of Building Construction of Barcelona (Technical University of Catalonia), Spain 2

Preliminary diagnosis is the stage of compilation of all the basic information required to enable the client to make a decision about the possible rehabilitation of a building. All too often, this stage is avoided or glossed over, yet it is vital for realistic decision-making in the rehabilitation process. Given the variety of types of data to be collected, this brief introduction is followed by a series of model forms for the process of preliminary diagnosis that may serve as guidance to the architect/engineer. The principal data is obtained by consulting the local Council (urban planning information, protection of architectural heritage, Council grants for the rehabilitation of private dwellings, etc.), conducting an inspection of the entire building (construction system, state of conservation, imminence of intervention, etc.), surveying the property market (market price of similar properties in the area, construction costs, rehabilitation costs, etc.), gaining an understanding of the socio-economic conditions of the building’s inhabitants (one-family ownership, a non-resident owner with tenants, possibility of vacating the building during rehabilitation work, etc.) and, finally, a series of interviews with the client to fine-tune the commission. There are three principal moments in the process of preliminary diagnosis. intéressants ;

Basic diagnosis kit (the “diagnostician’s bag”) for measuring, comparing and noting down information during the visit.

2. Visiting the building 1. Before visiting the building In order to make the most of the time spent on the visit, it is advisable to prepare it carefully in advance, arranging the day and time of the visit with a single person from the building who will be responsible for providing access to all parts of it. At this point, the important questions to ask are: Do I have the permission of all the owners and tenants to visit their dwelling or premises? Who will attend me in each case? Who has the key? Are there plans of the building? Does the building have unlit areas (basements, roof spaces, etc.) needing special lighting, a torch, etc.? Are all the spaces easy to access or will I need a stepladder, ropes, etc.?

The architect/engineer who carries out the inspection visit must have a well-trained and practised eye, and be patient (not be tempted to jump to conclusions about the cause of problems), curious (not simply suppose things that it has not been possible to establish) and imaginative (measuring, checking situations in the course of the visit during which tests may be carried out). The site visit will be conducted according to an order and organization that prevents any elements or determinant problems being overlooked. For example, the route followed by the inspection will start on the outside of the building, offering a clear view of the lesions and symptoms that will be explored in greater detail during the full visit, at the same time allowing us to form an overall idea of the building. Once inside, it is advisable to follow the elements of vertical communication up to the roof, as they are ideal points from which to observe the building’s basic structure and drainage system, locate possible structural movements or leaks, and complete our knowledge by means of initial sketches. Once a clear idea has been formed of the whole and the building’s

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main features, it is time to move onto a more detailed examination, with a strictly organized visit to form a balanced initial assessment of all components and prevent attention centring on specific aspects. During this preliminary diagnosis stage, the form, precision and quantity of information to be collected are, of course, different to those of the subsequent stage of multidisciplinary studies. This initial moment is characterized by a search for fundamentally qualitative values. The diagnostician’s bag Below, though in no way pretending to be exhaustive, is a list of tools that may be useful when carrying out a technical inspection of a building and which are increasingly joining the contents of what I refer to as the “diagnostician’s bag”. This is not a comprehensive list of the tools needed for any type of inspection; it is merely a few suggestions with a view to preparing the inspection, which must be assessed according to the objectives set, the type of building to be studied, its constructional characteristics and the lesions that have been detected.

Tool 2 Starting with a precise preliminary diagnosis Support material for the preliminary diagnosis stage

For greater ease of use of this list, the tools—like the contents of the doctor’s bag used in the examination of a person—have been grouped into five sections. Collecting and representing the information Drawing board, paper, pencil, rubber, pens, etc. Inspection sheets for the systematic collection of information Plans or diagrams on which to record interesting aspects Digital camera Camera with different lenses to take quality photos of general views or details and inaccessible places Pocket tape recorder For geometric measurements 5-m flexible tape measure 25-50 m measuring tape Sonic measure and laser distance meter, to take measurements in inaccessible places Telescopic tape measure for measuring façades Tachaeometer Automatic level Manual level Flexible tube water level Steel ball Picks and ropes Bevel protractor Slide gauge Weaver’s glass Plumb line Compass For greater ease of observation Protected light bulb and electrical cable Torch Magnifying glass Binoculars Flash Lightweight ladder Pulley Adhesive paste or tape For taking samples

Consult municipal regulations for information about urban planning and possible listing of the building.

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Hammer, chisel and screwdriver Plastic bags and boxes to store samples in (e.g. slide boxes) Adhesive labels to mark samples Permanent marker pens


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Tool 2 Starting with a precise preliminary diagnosis Support material for the preliminary diagnosis stage

I. Knowledge

Checking and detecting lesions Knife Punch Metal detector Damp detector Concrete pH test kit Reagents to check the existence and type of salts The examination visit must envisage possible dangers arising from the state of the structure or the installations, health and hygiene conditions, abandonment, etc., and this calls for specific protection that is not listed here, but may range from boots to protect against nails and insecticides to kill bedbugs to a whole range of equipment, depending on the circumstances (overalls, cap, helmet, goggles, safety harness, mask, tool jacket, gloves, etc.).

2

Use systematized sheets for greater ease of data collection during the inspection.

3. Back in the office All the information compiled during this phase will serve to help the client make a decision. This phase is therefore usually completed by a written preliminary diagnosis report that clearly and succinctly suggests a course of intervention to the client (from inaction or a campaign of studies preparatory to rehabilitation work to immediate vacation of the building due to the risk of accident).

The additional equipment needed to reach all parts of the building.

Optical measurement of cracks

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Tool 2 Starting with a precise preliminary diagnosis Support material for the preliminary diagnosis stage

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Model preliminary diagnosis sheet INFORMATION ABOUT THE BUILDING Owner:

2

Contact data: Address: District / Town: Number of basement floors:

Number of floors:

GF+

Privately owned Number of shops:

Privately owned Number of dwellings:

Rented Age in years:

Rented Built depth:

Built surface area:

m2

m

Surface area of courtyards and gardens:

m2

MUNICIPAL URBAN PLANNING INFORMATION Urban planning classification (permitted uses):

Designation of public property, censuses, mortgages:

Heritage listing:

Building levels:

Permitted number of floors:

GF+

built m2 / m2 land

Permitted building depth:

m

Distance to urban centre:

km

SITE CHARACTERISTICS Area (urban/rural): Street width: Height of adjacent building on left:

m GF+

Pavement width: Height of adjacent building on right:

UTILITIES Drinking water:

Electricity:

Sewerage:

Telephone:

SKETCH OF THE BUILDING

102

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Test to evaluate the buiding’s state of conservation Elements

Description

Condition

Urgency

Recommended action

STRUCTURE (Ensure coherence of load transmission) Walls and/or columns Floors

2

Stairways Roof structure ROOF (Ensure evacuation of rainwater) Roof cladding Eaves Chimneys FAÇADE (Ensure thermohygrometric behaviour and prevent detachment of material onto street) Claddings and renderings Balconies Door and window frames Railings, grilles INSTALLATIONS (Guarantee functioning and user safety) Water Drainage Electricity Gas HABITABILITY (Ensure salubrious conditions of the dwelling) Ventilation of rooms Damp in the interior Position and ventilation of WC Fire safety Dangerous materials HERITAGE ASSESSMENT (Find out the building’s historical and artistic values) Spatial structure Ornamentation Singular elements Historical value ECONOMIC ASSESSMENT (Calculate the cost of the intervention) Market value without maximum building levels [VWMB]: Upper-level market value at maximum building levels [MBV]: Replacement value + land:

Superficial rehabilitation of existing m2 [SRV]: Comprehensive rehabilitation of existing m2 [CRV]: Rehabilitation with maximum m2 building levels [RMB]: New construction [VNC]:

OBSERVATIONS

CONCLUSIONS AND RECOMMENDATIONS

CONDITION

URGENCY

1- Good condition 2- Lack of maintenance 3- Poor condition

A- Immediate intervention B- Intervention within 2 years C- Intervention within 5 years

Conducted in

on

SIGNED BY THE ARCHITECT/ENGINEER

Name:

20

The information included in this document is valid for the following 6 months as of the above date.

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Economic study [preliminary diagnosis] CURRENT STATE OF BUILDING Owner:

2

Contact data: Address: District / Town: Number of basement floors:

Number of floors: Privately owned

Number of shops:

Rented

Age in years:

GF+ Privately owned

Number of dwellings:

Rented

Plot width:

m m

Surface area of site [SS]:

m2

Built depth:

Built surface area [BS]:

m2

Surface area of courtyards and gardens:

m2

MUNICIPAL URBAN PLANNING INFORMATION Urban planning classification (permitted uses):

Designation of public censuses, mortgages:

Heritage listing:

Building levels [BL]:

Permitted number of floors:

GF+

property, built m2 / m2 land

Permitted building depth:

m

Distance to urban centre:

km

SITE CHARACTERISTICS Area (urban/rural): Market study (sales price of 6 buildings of similar characteristics) Built m2 [CTC]

Built m2 [CTC]

Sales price [CSP]

Sales price [CSP]

Control 1

m2

__

Control 4

m2

__

Control 2

m2

__

Control 5

m2

__

Control 3

m2

Control 6

m2

__

Average sales price of similar buildings in the area [ASP]=(∑ (CSC / CTC) / ∑i) :

__ __ /m2

Percentage of repercussion of area land price [LP]:

Price of new construction in the area [NCP]:

__ /m2

Price of demolition [PD]:

__ /m2

Price of superficial rehabilitation [SRP]:

__ /m2

Price of comprehensive rehabilitation [CRP]:

__ /m2

Direct costs of construction in the area

ECONOMIC ASSESSMENT Maximum surface area to be built [MSB]=(SS x BL)

Planning impact [IP]=(MSB / BS)

Cost of superficial rehabilitation work [CRW]=1.18 x (BS x SRP)

Cost of comprehensive rehabilitation work [CRW]=1.18 x (BS x CRP)

Cost of rehabilitation work with maximum m2 building levels [CRMB] = 1.18 x (CCRW+ (MSB-BS) x 1.5 x NCP)

Cost of new building work [CNBW]=1.18 x ((BS x PD) + (MSB x NCP))

Market value

Value of replacement + land value:

[VWMB]=[1.1 x ASP x BS]

[MBV]=[1.1 x ASP x MSB]

[SRV]=[CSRW+LP*ASP*BS] [CRV]=[CCRW+LP*ASP*BS] [RMB]=[CRMB+LP*ASP*MSB] [VNC]= [CNBW+LP*ASP*MSB]

The information included in this document is valid for the following 6 months as of the above date.

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Tool 2 Starting with a precise preliminary diagnosis Support material for the preliminary diagnosis stage

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Model preliminary diagnosis sheet (example) INFORMATION ABOUT THE BUILDING Owner:

Pedro Jiménez Solera

Contact data:

8660660505

Adress:

Calle de Entresols, 22

District / Town:

Mataró

Number of basement floors:

Number of floors:

-1

2

GF+ 1

Privately owned

Number of shops:

1

Privately owned

--

Rented

Built depth:

15

m

Surface area of courtyards and gardens:

80

m2

None

Number of dwellings: --

Age in years:

Over 100

Built surface area:

150

Rented

m2

MUNICIPAL URBAN PLANNING INFORMATION Urban planning classification (permitted uses):

Residential, old town

Designation of public censuses, mortgages:

property,

Heritage listing:

None

Building levels:

1.10

built m2 / m2 land

Permitted number of floors:

GF+ 2

Permitted building level:

14

m

Area (urban/rural):

Urban

Distance to urban centre:

--

km

Street width:

7

Pavement width:

1

m

Height of adjacent building on left:

GF+ 1

Height of adjacent building on right:

GF+ 3

Drinking water:

YES

Electricity:

YES

Sewerage:

YES

Telephone:

YES

SITE CHARACTERISTICS

m

UTILITIES

SKETCH OF THE BUILDING

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Tool 2 Starting with a precise preliminary diagnosis Support material for the preliminary diagnosis stage

I. Knowledge

Test to evaluate the buiding’s state of conservation Elements

Description

Condition

Urgency

Recommended action

STRUCTURE (Ensure coherence of load transmission)

2

Walls and/or columns

Masonry

1

--

Renew exterior rendering to ensure ongoing protection

Floors

Timber beams

2

C

Ask for a structural diagnosis

Stairways

Timber beams

2

C

Ask for a structural diagnosis

Roof structure

Timber truss

3

A

Shore up damaged parts and get a structural diagnosis

ROOF (Ensure evacuation of rainwater) Roof cladding

Roofing tiles (channel and imbrex)

2

A

Change broken tiles after shoring up the roof

Eaves

Timber

3

A

Shore up eaves and get a structural diagnosis

Chimneys

Brick

--

--

FAÇADE (Ensure thermohygrometric behaviour and prevent detachment of material into street) Claddings and renderings

Lime rendering

2

B

First solve structure and roof problems then renew rendering

Balconies

--

--

--

--

Door and window frames

Timber

2

B

General repainting

Railings, grilles

Wrought iron

2

B

General repainting

Gallery with arches

Brick

1

--

--

INSTALLATIONS (Guarantee functioning and user safety) Water

Copper tubes (recently replaced)

1

--

--

Drainage

Cement asbestos tubes

2

B

Install new downpipes

Electricity

2 circuits, 4.4 kw of power (recently renewed)

1

--

--

Gas

Gaz butane (rénovée récemment)

1

--

--

HABITABILITY (Ensure salubrious conditions of the dwelling) Ventilation of rooms

2 bedrooms are not ventilated

3

C

Plan intervention to create windows in the mid-term

Damp in the interior

Generalized damp in walls and floor at ground level

3

A

Ask for a diagnosis to find out the cause of damp

Position and ventilation of WC

Next to stairwell, no ventilation

3

B

First solve the structural problems then find a new position for it

Fire safety

Irregular risers in stairs

1

--

First solve the structural problems then renew stairway

Dangerous materials

Cement asbestos tubes (asbestos)

2

B

Get a specialized company to replace them

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HERITAGE ASSESSMENT (Find out the building’s historical and artistic values) Narrow bay on medieval plot, medieval aproach and hallway conserved

1

Ornamentation

Lintel over front door

1

--

--

Singular elements

Timber eaves with carved decoration

3

A

Reconcile structural reinforcement and conservation of decoration

Historical value

Situated in one of the district’s historical streets, well conserved

2

C

Conserve façade

Spatial structure

--

Conserve approaches

2

ECONOMIC ASSESSMENT (Calculate the cost of the intervention) Market value without maximum building levels [VWMB]:

504,485 €

Upper-level market value with maximum building levels [MBV]:

573,430 €

Replacement value + land:

Superficial rehabilitation of existing m2 [SRV]:

358,442 €

Comprehensive rehabilitation of existing m2 [CRV]:

429,242 €

Rehabilitation with maximum m2 building levels [RMB]:

539,117 €

New construction [VNC]:

537,878 €

OBSERVATIONS

The building is an excellent example of the traditional architecture of the old town. It was originally a solid building for a humble family that has been extended various times over the years. Probably only the ground floor conserves medieval elements.

CONCLUSIONS AND RECOMMENDATIONS In the last 10 years, the building has undergone a major process of degradation. The absence of maintenance has led to rainwater leaking into the interior, causing the deterioration of the timber structure of the roof and upper floor. At the same time, the building is situated in one of the district’s oldest streets and forms part of a whole that is of modest construction but with a high historical value. Recommendations: - Shore up the damaged structure under the direction of an architect/engineer - Ask for a complete diagnostic study of the building (structural analysis, damp study, historical study) - Consider a rehabilitation project, since an initial cost study does not suggest the advisability of demolition and the building has historical value in the street where it is situated. CONDITION

URGENCY

1- Good condition 2- Lack of maintenance 3- Poor condition

A- Immediate intervention B- Intervention within 2 years C- Intervention within 5 years

Conducted in

Mataró

on

20 January

SIGNED BY THE ARCHITECT/ENGINEER

20 0 6

Name :

Julián Almagro Pérez, architect

The information included in this document is valid for the following 6 months as of the above date.

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Tool 2 Starting with a precise preliminary diagnosis Support material for the preliminary diagnosis stage

I. Knowledge

Economic study [preliminary diagnosis] (example) CURRENT STATE OF THE BUILDING

2

Owner:

Pedro Jiménez Solera

Contact data:

8660660505

Address:

Calle de Entresols, 22

District / Town:

Mataró

Number of basement floors:

--

Number of floors:

1

Privately owned

--

Rented

Number of shops:

GF+ 1 1

Privately owned

--

Rented

Plot width:

5

m

Number of dwellings:

Age in years:

Over 100

Surface area of site [SS]:

155

m2

Built depth:

15

m

Built surface area [BS]:

150

m2

Surface area of courtyards and gardens:

80

m2

MUNICIPAL URBAN PLANNING INFORMATION Urban planning classification (permitted uses):

Residential, old town

Designation of public property, censuses, mortgages:

None

Heritage listing:

None

Building levels [BL]:

1.10

built m2 / m2 land

Permitted number of floors:

GF+ 2

Permitted building level:

14

m

Urban

Distance to urban centre:

--

km

SITE CHARACTERISTICS Area (urban/rural):

Market study (sales price of 6 buildings of similar characteristics) Built m2 [CTC]

Built m2 [CTC]

Sale price [CSP]

Sale price [CSP]

Control 1

140

m2

450,000 €

Control 4

200

m2

Control 2

135

m2

440,000 €

Control 5

125

m2

410,000 €

Control 3

160

m2

470,000 €

Control 6

130

m2

410,000 €

Average sales price of similar buildings in the area [ASP]= (∑ (CSP / CTC) / ∑i) :

3,057 € /m2

Percentage of repercussion of area land price [LP]:

Price of new construction in the area [NCP]:

1,200 € /m2

Price of demolition

Price of superficial rehabilitation [SRP]:

600 € /m2

500,000 €

0.55

Direct costs of construction in the area

Price of comprehensive rehabilitation [CRP]:

55 € /m2 1,000 € /m2

ECONOMIC ASSESSMENT Maximum surface area to be built [MSB]=(SS x BL)

171

Impact of planning [IP]=(MSB / BS)

m2

1.14

Cost of superficial rehabilitation work [CSRW]=1.18 x (BS x SRP)

106,200 €

Cost of comprehensive rehabilitation work [CCRW]=1.18 x (BS x CRP)

177,000 €

Cost of rehabilitation work with maximum m2 building levels [CRMB] =1.18 x (CCRW+ (MSB-BS) x 1,5 x NCP)

252,402 €

Cost of new building work [CNBW]=1.18 x ((BS x PD) + (MSB x NCP))

251,163 €

Market value [VWMB]=[1.1 x ASP x BS]

[MBV]=[1.1 x ASP x MSB]

Replacement value + land value: [SRV]=[CSRW+LP*ASP*BS]

358,442 €

[CRV]=[CCRW+LP*ASP*BS]

429,242 €

504,485 € [RMB]=[CRMB+LP*ASP*MSB]

539,117 €

[VNC]= [CNBW+LP*ASP*MSB]

537,878 €

573,430 €

The information included in this document is valid for the following 6 months as of the above date.

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Tool 2 Starting with a precise preliminary diagnosis

The preliminary diagnosis The Cyprus experience

I. Knowledge

Yiola Kourou Architect Department of Town Planning and Housing, Cyprus

2

The restoration and rehabilitation of Cyprus traditional buildings, is driven mainly by the initiative of the buildings’ owners. Once the decision to proceed with a general preservation of the building is taken, a certified designer (Architects and Civil Engineers) is appointed. The designer is then informed about their desired outcome, either for rehabilitating the building for residential use, or for financial exploitation. In the urban historical centers, the main use of the traditional buildings is residential; the commercial use is usually restricted to the central commercial streets. On the contrary, in the villages, due to the accumulating decrease of the population caused by the lack of job opportunities, the required use is mainly commercial (agro tourism) combined with secondary residential use (holiday houses). After the appointment of the designers, the first on-site visit takes place for the visual inspection of the building. The poor condition of large number of traditional buildings appears to be an overwhelming factor. Many of these buildings have been abandoned and special attention must be exercised for their restoration. Quite often they require special supports prior to intervention or else a step by step execution of the restoration works. During the above visit, a preliminary study of the following elements takes place: a. The construction materials (stone walls, adobe walls, lightweight walls etc), their condition and any interventions pointing out mechanical and stability safety problems, moisture problems etc. that need to be addressed immediately (i.e. support of the building). b. The buildings’ construction (i.e. the frame, the interlocking and connection of the elements and their contribution to the overall stability of the building); this could be very helpful when deciding the removal of some sections of the internal walls in order to achieve better functionality of the building according to the owners wishes, provided that the authentic character of the building is not negatively affected. c. The existing functionality of the building (i.e. how the rooms connect to the street or to the internal yard) in order to be taken into account in the planning phase for the new use of the building. A complete documentation with the use of sketches and photographs should take place. All problems identified such as

Lefkara (Cyprus)

damages, cracks, deterioration etc, must be documented. This is a very important part of the work, since it will assist the architect and/or engineer to understand the behavior of the structural system and trace the probable causes that originally produced the damages. The evaluation of the architectural and historical character of the building, as well as its position in the historical centre is very important. This must also be documented in order to be taken into account when acquiring Listing/Ancient Monument status. Moreover, the architect proceeds to an on-site investigation interviewing neighbors and senior citizens of the area, in order to collect data for the original character of the building, for any interventions, or for any other relative information. The next step is to establish a contact to the corresponding competent authorities for the designation of the building’s legal status and the urban planning obligations and restrictions through the Local Plans and the Policy Statement for the Countryside, whereas, in the cases of highly acclaimed settlements such as the Lefkara settlement, there are guidelines for the protection of the character of the historical centers with the preservation of the morphology and typology of original buildings (traditional types of walls, types of openings, inclinations and types of roofs, use of regional traditional materials, correct interventions in external and internal additions/extensions to the building etc.). In the case of Listed Building/Ancient Monument, additional restrictions apply because the building must comply with the principles of Preservation: a. The conservation of a building means also the conservation of

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2

all its elements (original traditional materials, architectural details, decorative/painting elements etc.) as well as the conservation of its environment and its scale. This excludes any modification leading to the change of volumes, typology, materials and colors. b. The new extensions/additions must respect all parts of the building, its traditional framework and the connection of the environment; in parallel, they must differentiated from the original parts of the building and be reversible as possible, allowing the recall of the pre-interventions status of the building (principle of reversibility). c. To use, in general, traditional materials and construction methods; only in cases that these cannot be applied, modern methods with proven efficiency (empirically and scientifically) and compatibility with the traditional materials can be used instead.

Wall built of light materials (ntolmas – timber structure with infilling of plaster, reeds and stone), Nicosia

Traditional structural floor, Lefkara

110

Tool 2 Starting with a precise preliminary diagnosis The preliminary diagnosis. The Cyprus experience

d. All uses allowed by the Planning Zones can be applied to Listed Buildings/Ancient Monuments under the condition that the special character of the buildings (typology and morphology) is respected. In the cases of designated buildings or other structures, the Cyprus Government has developed and established a generous package of incentives. As an example, the package of incentives currently available for listed buildings includes direct cash grants for up to 50% of the approved restoration cost for listed buildings located within rural settlements or in the countryside and 40% for urban listed buildings (with a maximum amount of grant C£40.000,00 in both cases), transfer of “Residual Building Coefficient” (only for urban listed buildings), “Donated Building Coefficient” so that the owner may sell extra square meters to increase the amount of the grant up to 50% in cases when it is less, tax exemptions ( including exemptions of restoration costs and rents obtained from a listed building from income tax, exemption of property tax and refund of property transfer fees). The package of incentives currently available for ancient monuments includes direct cash grants for up to 50% for the first C£60.000,00 of the restoration cost, 30% for the next C£40.000,00 and 10% for the rest of the restoration cost for buildings of residential use and direct cash grants for up to 30% for the first C£60.000,00 of the restoration cost, 20% for the next C£40.000,00 and 10% for the rest of the restoration cost for buildings of commercial/tourist use (with a maximum amount of grant C£50.000,00 in both cases) and tax exemptions. With the collection and study of the above elements, the designers brief the owner of the building of their preliminary findings, views and proposals for the restoration/rehabilitation plan to be followed (requirement of supports, proposed use, application for listing of their property as historic/ancient monument), before the kick off of the main study of the building.


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Tool 3 Overall knowledge of the building

The programme of studies

I. Knowledge

Fernando Vegas Doctor of Architecture Lecturer in the Department of History and Theory of Architecture, School of Architecture of Valencia (Technical University of Valencia), Spain Camilla Mileto Doctor of Architecture Lecturer in the Department of History and Theory of Architecture, School of Architecture of Valencia (Technical University of Valencia), Spain

This is the starting point: a traditional construction needs fitting out, repairing or restoring. This construction may be a traditional dwelling (private or collective, isolated or clustered), premises linked to the pre-industrial economy (a windmill, tile works, press, olive-oil mill, stables), a modest religious construction (chapel, small sanctuary) or a functional structure associated with farming, stock-keeping or hunting (terrace, wall, cobbles, canal, waterwheel, dike). There are two possibilities: either the vernacular techniques that produced these constructions are still alive in the place or they now form part of the past and the place no longer conserves the knowledge of the master builders from days gone by. In the first case, supposing the techniques are still truly alive in the area, the fitting out, repair or restoration can be easily undertaken employing the same construction systems used to build the traditional architecture. The second case requires a detailed study of the existing construction to discover these construction techniques and carry out the best possible intervention. In both cases, prior to any study and by way of a general recommendation, the scrupulous conservation of pre-existing elements is urged as opposed to the oft-considered alternative of demolition and complete rebuilding, even when vernacular construction techniques are still active. In these cases, it is often discovered after demolition that reconstruction is not so easy after all, or that the necessary processes are not actually known, despite having thought the contrary. Furthermore, the presence of pre-existing elements is always an open book that provides reference to the knowledge required to draft and construct a project.

The preliminary study Before the restoration project is carried out, a preliminary study of the building is necessary to acquaint us with the architecture in question and allow us to produce a project in keeping with its reality and its real needs. If few means are available, the

3

A historical study can be based on historical photographs that reveal unknown information about the building. Church-fortress in Castielfabib (Valencia)

preliminary study can be limited to a detailed inspection in order to interpret the point of departure, before intervention, with the help of the experience of similar cases. If means are available, then the preliminary study can be as detailed as you like, as there are no bounds to knowledge, even in the case of simple traditional constructions. As we will see further on, an exhaustive preliminary study does not guarantee correct restoration, which ultimately depends on the attitude or criteria of the designer or actor. It is also true that fuller knowledge of the built reality often allows a more sensitive approach to restoration, as sensibility increases with greater contact with the building. Ultimately, however, the strict conservation of traditional architecture depends not on the profusion of multidisciplinary studies—which can often not be undertaken due to their proportional cost in relation to the intervention—but on the criteria, respect and sensibility displayed by the actor or actors in

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Tool 3 Overall knowledge of the building The programme of studies

the intervention. For this reason, it is advisable that universities and research centres undertake multidisciplinary studies to give various ideas about the traditional architecture of each place or types of vernacular techniques, facilitating the work of the architects and owners who, due to lack of training, knowledge or means, cannot undertake a complete study of these buildings. A comprehensive programme of preparatory studies for a restoration project might include the following: historical study, metric and descriptive plan, photographic plan, plan of construction and materials, stratigraphic study, study of pathologies, study of fissures and deformation, functional study and other, more specific complementary studies. It is up to each actor to decide which studies are necessary in each case, according to the needs and means available. Historical study However difficult it may initially seem, it is important never to leave out a historical study, albeit simple, of the traditional building requiring rehabilitation or, in its stead, of the surroundings, area, village or town in which it is located. This historical study may be a simple recompilation of old photos of the building, the documentation of oral sources gathered with due precaution as regards possible partiality or subjectivity, the study of buildings of similar morphology, the consultation of previous cases of restoration, and so on. Metric and descriptive plan This is the most exact graphic reproduction of the built reality. It must faithfully reflect the object represented, since it will provide the basis for the rest of the preliminary studies and the project itself. Discontinuities, irregularities and deformations must be precisely drawn, with no attempt to simplify or impose a geometric order, as they usually conceal clues to understanding the building’s growth, historical evolution and pathologies. There are many ways of measuring and describing buildings, from manual means, using a tape measure and triangulation, to recent 3D scanning systems, to the laser distance metre, the theodolite and photogrammetry. The most natural in the case of traditional architecture is the use of manual means, which, if carried out efficiently in these simple constructions, does not compare unfavourably in precision with more technological means. It is necessary to draw out as many floor plans as there are levels in the building and as many cross- and longitudinal sections as there are different situations in the layout. The projection of the interior elevations in these sections will subsequent help to locate the project in the interior of each room. When drawing up these plans, it is advisable not to take any relation in a vertical direction as read, as walls often decrease in height or slope away from the vertical. For this reason, it is a good idea to fix at least three external or internal points of connection

114

The metric and descriptive plan may be accompanied by the interior elevations of the building reflecting the expressivity of the material. Old waggoners’ inn in Torrebaja (Valencia))


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between the various floors to facilitate the subsequent location of the floors with reference to them. Similarly, it is important not to take as read the existence of horizontal planes, as both ground and upper floors often have deliberate slopes, pathological inclines or structural deflection that may be very useful to understanding the building and drawing up the restoration project. The mapping of arches, vaults and domes has to faithfully reproduce their trajectory in space, producing at least one section for each curve, and a series of sections in the case of a longer vault. These curves in section, compared to the theoretical line of pressure, allow us to analyse the state of health of the construction element. Photographic plan This is basically for the building’s external and internal façades. It involves producing a map with the help of photographs superimposed with data (photomaps) and put together like a puzzle. This requires the use of a computer, as it involves taking digital photographs (or photos that are then scanned), rectifying them using one of the many computer programs currently on the market, manipulating them and printing them to a certain scale. A photographic plan of a building’s façades or a photomap is far more powerful in terms of expression and communication than the information offered by a metric and descriptive plan. A photomap represents the object with its exact measurements, but it also provides information about the colour, material, texture, state of conservation, etc. A scale photomap offers the same information as the metric and descriptive plan, plus a great deal of added data that the drawing is unable to reflect, to the extent that it can replace the first mapping. In fact, if you have a photographic map, you can produce the metric and descriptive plan by tracing the information provided by the photomap in line form. This might initially seem a pointless task. However, the manual exercise of reproducing the lines provided by the photograph reveals to the hand things that go unnoticed to the eye. However, it is not important if the means to draw up a photographic map are not available. Simple photographic documentation to accompany the metric and descriptive plan allows the same type of real approach to the architectural object and provides the same amount of information as a photomap, with the difference that the measurements can only be obtained from the metric and descriptive plan. Plan of construction and materials This plan is drafted on the physical support of the metric and descriptive plan or the photographic map. Its purpose is to identify and name all the types of materials used: the types of masonry and their respective bonding, the bricks, the rammed-earth walls,

I. Knowledge

the mortars, the interior plasters, the exterior renderings, the timber used for the beams, joists, door and window frames, the partition walls, the uprights, the glass, types of floors, roofs, tiles, flooring, and so on. And not only the materials, but also the way they are grouped and combined to form the constructional details of the building that have two aspects to be considered: function and mutual physical compatibility. What is the objective of this task? The precise identification of the various construction materials and techniques used in the building firstly facilitates the drafting of the stratigraphic study but secondly, and most importantly, it represents a step further in knowledge of the built object, allowing us to choose and design the best processes of consolidation, treatment and repair of the individual elements that form part of the whole. By way of example, a wall of bonded masonry or plaster made with earth or lime mortar are different things, and each element requires different attention. Various types of timber behave differently in the event of damp and the attacks of wood-boring insects and fungi. Precise knowledge of a constructional section can provide explanations for a building’s pathologies, and this is just one example.

Photomaps are a very useful technique. In addition to measurements, they also record colour, texture, degradation, etc. Old waggoners’ inn in Torrebaja (Valencia)

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The plan of construction and materials provides a detailed description of the structural functioning of both the parts of the building and the whole. Traditional house in Sesga (Valencia)

Stratigraphic study This is a study of the evolution of growth, and the extensions and modifications made to the building. It does not require written historical documentation or information that can be found in libraries or archives. If such documentation does exist, it should not be disregarded, but this very rarely is the case with traditional architecture. The stratigraphic study is written directly by reading the signs contained in the built fabric. The objective of the stratigraphic study is to produce a chronology that tells of the phases in the life of a building, with all the cases of extension, transformation and demolition, etc. This reading calls for some practice and the adoption of a code that allows us to record on the plans the information about the structure as we obtain it. In this case, the photographic map or simple photographs without scale are preferable to the metric and descriptive plan, due to the importance of the added documentation that the photograph provides. If you have drawn up a plan of construction and materials, you will be better placed to draft the stratigraphic study, since you will

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have refined your knowledge of the various changes of stonework that appear in the building, which, on occasion, correspond to the different phases of construction. Likewise, irregularities and discontinuities found in the walls during the drafting of the floor plan will be possible points of information for the stratigraphic study. It is also interesting to cross-reference the information obtained from the stratigraphic study with the building pathologies, as the building’s healed-over wounds, listed within its overall chronology, contribute information about the active or inactive presence of the factor causing the pathologies. For example, a small crack in a plastered wall may correspond to a large crack that has been repeatedly repaired during the life of the building and successively covered up by multiple layers of plasters of differing ages. Study of material pathologies The detection, identification and study of the building’s pathologies are the necessary preliminary to drawing up a restoration project that will ensure the building’s return to overall health. Pathologies are normally manifested in the surface of built elements, though there are also cases, such as a possible termite attack, when the affected material—in this case timber—does not


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The stratigraphic study reveals data not recorded in any written documents but present in the stonework. Traditional house in Sesga (Valencia)

present any signs on its surface, and it will be necessary to look for other signs of its existence. Before starting, it is important to distinguish between two types of phenomena: alterations and degradations. Alterations are modifications in the material that do not necessarily involve a worsening of its characteristics from the viewpoint of conservation. Degradations, conversely, are transformations in the material that do represent a worsening that endangers its integrity and permanency. Alterations do not compromise the existence of the building and are therefore not the object of concern or intervention—on the contrary, they mark the effects of the passing of time on the building and, within reason, form the patina that allows the observer to identify the value of its age. Degradation, conversely, should receive attention, as ignoring it could compromise the existence of the building in the short, medium or long term, depending on the gravity of the case. It is important to reflect on the plans all the observations made about the stonework with regard to the phenomena of degradation present in the surfaces of the materials. In mineral materials, such as masonry, rammed earth, mortar or plaster, these

phenomena may be superficial or deep-seated erosion, air pockets, disintegration, flaking, pockmarking, spalling, subflorescence, etc. Of the materials of animal origin occasionally used in construction, such as leather, bone (horn), animal fibres (wool) or the various additives used to make mortar in different parts of the world (eggs, glues, fibres, hair, honey, etc.), it is animal fibres that are most subject to attack by moth and similar insects. In plant materials such as timber, reed, wicker or straw, the phenomena of degradation may be the various types of biological attack by fungi or wood-boring insects (anobids, curculionids, termites, etc.). Study of fissures and deformations The overall symptomatology of the cracks and deformations in the traditional construction as a whole provides valuable data about the building’s structural pathologies. Often, the simple observation of an isolated crack, without the context of fissuring and deformation of the whole building, may be deceptive. Likewise, sometimes the confluence of various phenomena can cloud a hasty initial examination lacking in thorough analysis. The record of fissuring should be made on the metric and

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The recording of pathologies on the metric plan is another step towards the restoration project. Old waggoners’ inn in Torrebaja (Valencia)

descriptive plan or the photographic map. It is advisable to create a legend of signs to easily distinguish and identify the type of lesion documented. A superficial crack in plaster is not the same as one that goes through to the building’s walls. It is also important to carefully observe each lesion and identify its direction, rotation and which way it is moving. In order to do so, observe the two sides of the crack and find out whether they are in the same plane or displaced, whether they are parallel or meet, if they run right through the wall or open in just one face, and so on with each lesion. The study of deformations will be included in a carefully conducted metric and descriptive plan. Here, the combination of data about these deformations and the study of cracks reflected in the plans will produce a diagnosis of the structural movements being undergone by the stonework. Comparing and contrasting this data with the information obtained by the stratigraphic study may in some cases prove the present inactivity of an old lesion or, conversely, its continuing activity.

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Functional study Before going on to draft a restoration project, it is advisable to carry out a study of the historical function of the building and its compatibility with the future function assigned to it. This prior analysis may detect possible incongruence in the concept or distributive violence that is inadvertently being caused to the building in time to correct the course of a functional programme or a preliminary project that does not adequately address preexisting elements of the traditional building and the necessary prevalence of its constitution and character in the restoration project. Complementary studies There is a whole range of more specific complementary studies that are normally reserved for interventions on a larger scale with bigger budgets, as in the case of public monuments. Some of them are listed below in the event of a specific case of restoration requiring them and the existence of sufficient technical and economic means to carry them out:


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The functional study of the building’s past will help to provide a reasoned function for its future after restoration. Traditional house in Sesga (Valencia)

A detailed study of cracking and deformation of a building helps to explain the historical evolution of its afflictions and the reasons for them. Apartment building in Plaza del Pilar, Valencia

Archaeology: excavation of the subsoil of the building or its environs to discover traces of its past or investigate the foundations Soil mechanics: reading of the subsoil from the surface using magnetic, electrical and ultrasound surveying systems Chemical and petrographic characterization: analysis of samples of stone, mortar or plaster to find out their nature and material composition Dendrochronology: determining the age of the timber used in a construction by observing the growth rings Biological studies: research into insect plagues, the presence of higher and lower vegetation, and how they affect the materials used in the building Climatological studies: analysis of the effects of rain, hail, wind, solarization, freezing and thawing cycles, and annual droughts on the building’s state of conservation Seismic vulnerability: the weak points of a building in the event of telluric movement in the place

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Historical studies and archaeological interventions: Tools for the knowledge of Traditional Mediterranean Architecture

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Abdellatif Marou NSAP diploma (Institut National des Sciences de l’Archéologie et du Patrimoine, Rabat) Assistant conservator of historical monuments and sites, Inspection des Monuments et Sites Historiques de Marrakech (Restoration), Morocco Jordi Ortega Historian, Barcelona, Spain

3 Montserrat Villaverde Art Historian and Lecturer in History of Architecture at the Escola d’Arquitectura La Salle, Barcelona

Some considerations The interest in traditional architecture, whether from the viewpoint of architecture, construction, anthropology or history, is relatively recent; the first attempts to form a systematic body of knowledge about this type of construction are barely 100 years old. Even more recent is the possibility of applying historical knowledge. The historical interpretation has been applied basically to sumptuary buildings and, as a result, palaces, cathedrals and mosques fill volume upon volume. The primary object of its discourse is formal analysis and symbolic interpretation, and it centres its reflection on the past. In this way, history is understood as the narrative of events that have taken place rather than a method for finding out about reality. It puts history on an equal footing with age, and age, in itself, is not a criterion of valuation, in this case.

Today, traditional architecture in the Mediterranean—or should we use Mediterranean as an adjective?—is an economic value on the rise and this circumstance, about which there is nothing gratuitous, involves different types of intervention. How many people fail to recognise their village, street or neighbourhood after processes of “regeneration” that reduce experience and lived events to caricature, and historical value to values that have nothing to do with its development in an attempt to fix supposed historical stage sets on our retinas? Historical studies do not seek to legislate intervention in traditional heritage; that is not their purpose. Their purpose is to contribute as much information as possible about the object of study, to be a factor contributing to its understanding and knowledge, at all times considering the nature of this architecture, seen in its permanent mutability. In this era of globalization, or cancelling out

The interest in traditional architecture is relatively recent. For centuries, studies have been based on monumental architecture. Tomb of the Kings of Judah. 1842. Private collection.

Historical studies must treat each building as a unique, unrepeatable work. Negative C-46374. 1925 IAAH-AM.

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of the specific in all fields, historical studies have to reinforce differences rather than similarities, and treat each building as a unique, unrepeatable unit. This understanding will facilitate rehabilitation in keeping with the evolution of the building.

On the symbolic interpretations of traditional Mediterranean architecture The symbolic interpretations to have recreated traditional architecture in the Mediterranean over the last three centuries have been innumerable and of differing natures. From idealized, picturesque, exotic, typical approaches to more creative, pedagogical readings, these interpretations convey different values of an architecture that has, as yet, been unable to cast off stereotypes. We find the first interpretations in the accounts of pilgrimages. The descriptions in the Rihlas1 centre mainly on the city’s more monumental buildings, like on the Grand Tour, quests for knowledge undertaken by an enlightened mentality, which offered descriptions of monumental Greco-Roman architecture. In both cases, though the nature of the journey was very different, the offerings of knowledge about traditional architecture were always incidental. Yet it was this same enlightened mentality that generated the first works of detailed analysis and description of some areas. An emblematic work is Yves Laissus’s Les savants en

Ethnographical and anthropological studies are a basic and necessary tool for understanding traditional architecture as a whole. Spain, 1940.

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Egypte2, the encyclopaedic rigour of which includes the description and analysis of an entire territory and society with a centuries-old culture. This masterwork includes splendid descriptions of the traditional crafts. Along the same lines, also the product of enlightened mentality, were the first, mainly descriptive studies of rural areas, such as the work of Gaspar Melchor de Jovellanos3 in Spain, and of construction, such as the work of Antoine Desgodets4 about building tradition in Paris. Although it was the Romantic artists who introduced popular themes into their highbrow works, the resulting creations were always idealized. References to local custom were incorporated into all artistic genres, from painting to short stories, including music. Recognising the influences of exoticism in the seguidillas in Bizet’s Carmen or visualizing the popular Sicilian ambiences in the tarantellas of Mascagni’s Cavalleria Rusticana are just a small example of how themes traditionally remote from everyday life progressively incorporate popular elements. Stage sets of traditional architecture The first sets of traditional architectures, Mediterranean or otherwise, can be traced back to the national and international exhibitions. As a result of progress and innovations, some exhibitions reproduced architectures that symbolized the unification of territories. A recently unified Italy organized the Italian General Exhibition in Turin in 1884, with the construction

The light and colour of Mediterranean cities are the most important values in the artistic production of the first half of the 20th century. Istanbul.

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Tool 3 Overall knowledge of the building Historical studies and archaeological interventions: Tools for the knowledge of Traditional Mediterranean Architecture

of a Borgo Medioevale that still exists today. Geneva hosted the Swiss National exhibition in 1896, triumphing with the construction of the Village Suisse, reproducing the country’s main traditional architectures. This was the precedent for the Pueblo Español built in Barcelona for the 1929 World Fair, one of the biggest draws of the entire event, which can still be visited today. As in the case of the Village Suisse, the Pueblo Español went further than the reproduction of architecture to create an ahistorical public space that denies any possibility of future, change or mutability. It is an island in time, a perfect set design, set outside time. Its streets have provided sets for all manner of recreations of the past. Last year, the most spectacular scenes of the film Perfume were filmed in its Plaza Mayor. It is both interesting and surprising to see how Jean-Baptiste Grenouille drives the whole town mad in the main square of Grasse, while in the distance we spy the Mudejar tower of Utebo in the Pueblo Español. In any case, it is quite natural that scenery should be used as such. What is more striking is the use and manipulation of certain natural settings, considered heritage for their value as traditional complexes, as film sets. Aït Benhaddou, in Morocco, still has a great doorway built in 1962 to film Lawrence of Arabia. This doorway is nearly as real/unreal as the sets built in 1937 in the Hollywood studies for the film Algiers, during which Pépé le Moko is chased by the police through the narrow streets of the Casbah.

In these circumstances, it is difficult to separate reality from fiction. New symbolic interpretations, developed in accordance with the needs of the tourist boom as of the mid-20th century, have turned old towns and rural areas into veritable theme parks, where the most important value is not just unbridled speculation on the territory and short-term profits on investment, but creating a standardized product that has almost all the characteristics of the typical villages of international exhibitions. Revitalizing the territory should not mean rejecting this architecture. Nor should it oblige us to create landscapes that never existed, overlooking their past and creating frozen images of indeterminate date.

Coinciding with their success at the 1929 World Fair, the journal La Ilustración Iberoamericana offered its readers this cut-out model of the church of Alcañiz and the bell tower of Utebo.

Today, the Mediterranean house has become a typical standardized retail product at newsstands.

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Traditional architecture and historical studies As outlined in the considerations above, no type of architecture is immutable, particularly if the architecture in question is traditional. Mutability and changes in configuration or appearance are implicit in traditional architecture, with remodelling or additions of new structural and ornamental elements. We are accustomed to a perception of architecture as something practically permanent and definitive, with almost imperceptible changes that are incorporated into our perception and rapidly fade from our memory. On these premisses, it is difficult to understand traditional architecture as mutable, fluctuating and elastic. Any element in any building, from its foundations to the smallest of decorations, is always the result of a precise happening in


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space, and also in time, and events related by links of causality, simultaneity or coincidence are what we might call a process. From a historical point of view, architecture is a process, in that time is vital to its configuration. A building has to be analysed from a chronological and, therefore, historical viewpoint. In very few cases does a chronological process achieve such a tangible and obvious physical concretion as in architecture and heritage. It is its most basic, elementary meaning because it provides us with intrinsic knowledge of the singularity and essence of each house. Each process is unique and unrepeatable, as are the results. No two buildings are the same, just as no two sequences are the same. Sequential development in traditional architecture is one of its fundamental characteristics. Irrespective of geographical situation, traditional architecture has always taken a long time to develop and its manifestations share an ongoing dynamic of adaptation and modification. It is the essentially utilitarian function of this type of buildings and their long chronological development that explains how a single building may include structural and decorative elements from different periods that may be conserved according to the criteria selected at different times as priority or pertinent. This architecture takes the form of the permanent juxtaposition and manipulation—addition or subtraction—of the existing elements. It therefore requires a dynamic, evolving approach that is never static.

Analysing the metacontext tells us why two buildings are alike and why urban centres are similar in structure.

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Approaching a methodology The need to know the context The analysis of the context involves as precise as possible a determination of the action, the agents taking part and the target of intervention. There is no reason why each event should have a single agent, and an action may be carried out or taken on by various, each with its own specific contextual circumstances. It is contextualization that gives significance to the event and knowledge of it, because it explains and gives specific meaning to its constructional form. The elements of context affecting a given action vary a great deal, ranging from maintenance to the repair or reconstruction of damage caused by war, natural disaster, etc., to other more subjective but equally relevant criteria such as need, ostentation, etc. To this end, two types of context can be distinguished: endocontext and metacontext. The endocontext is the conditions imposed most directly on the agents and, therefore, on their actions. It directly affects each one of the agents and is, in short, what most directly defines the motives of their actions: physical spaces, social condition and the immediate circumstances. The metacontext affects various agents at once and there is no direct control over it: regulations, customs, technical systems, symbolic values, etc. Knowledge of the city and the territory, their legislative and legal framework, and their cultural tradition will tell us why two houses are alike and inform us as to their similarities. Knowing who lives in the house, the activities that took place in it, the family members and their social representativeness will tell us why each house is different. In short, the endocontext explains why two houses are different and the metacontext explains why they are alike. The historical study has to prioritize the contextualization of each event in the house’s constructional sequence, because without knowledge of the context there is unlikely to be any knowledge of the action beyond the merely anecdotal. It is important to know who the agents were, what the house was used for, where it was, and how it was built and designed. This involves answering the basic questions what, when, how and why, which will underpin our knowledge. Contextualization prevents oversimplification and reductionism and allows us to identify and give value to singularities and discrepancies, and this is why the historical approach incorporates and interrelates evidence of all kinds and is, in itself, plural and integrative. The building as a document The building represents the action we have to analyse and, therefore, the most important and decisive tangible evidence. Each house contains within its structures and ornamentation a register of the actions that have gone to make it up. The building, then, represents the sequence of events that generated it, making

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it one of the most valuable documents for knowledge of its evolution. As documentary evidence of a historical and constructional process, all the elements that go to make up a building, be they structural or decorative, are forms that have an intrinsic meaning: types of walls, systems of flooring, etc. The textures and the materials reveal not only how the house was made but also when it was built, as these techniques, despite existing for a thousand years, have been modified. The characteristics of the mortar, the stereotomy of the stone, the structure, type and dimensions of the adobe, the formal characteristics of the decoration on the outside, are all fundamental to knowledge of the building. This is why the building represents a document: the document is everything that manifests what has happened. Destroying a building is like destroying a unique manuscript, and as such implies ignorance as well as forgetting The building as action: documentary sources The agents’ actions never take place in isolation and always involve interaction with other agents in the general context of which they form part. This circumstance suggests the possibility of these actions having been included in another type of graphic and written document—the more classical type known as documentary sources for historical knowledge. There is a whole range of useful documents of this kind depending on the geographical place, the moment in time and the cultural context. They represent a solid base of direct or indirect knowledge for understanding the actions, identifying the agents or determining some of the variables that may affect the endocontext or the metacontext. The graphic sources, such as planimetric diagrams, maps, photographs, drawings, etc. carried out at different moments in the building’s life provide a means for the precise interpretation of the construction process. Written sources provide an excellent basis for a more concise interpretation of the processes of transformation: contract of sale, title deeds (malkia), wills and habous titles, post-mortem inventories (trika), administrative authorizations, land registry and travellers’ accounts are all vital to discovering the events and the overall sequence. Attempts have been made to distinguish the validity of types of source, differentiating between structural evidence and graphic or written documentation, and seeking to establish the preeminence of one or the other, or accord greater validity to graphic than to written documents. This is a sterile debate based on false premisses: structures and documents are evidence of an event, and are different in methodology and content just as a photograph and a contract drawn up by a lawyer are, but they are essentially identical in their function of contributing relevant information about the construction process of a building. They function dialectically and reciprocally. Structures provide guidance

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Knowledge of the endocontext helps us to understand the building as a whole and why two buildings from the same period in the same street may be different.

The building is a document in itself and must therefore be analysed as such.

All the elements of a building, including its ornamentation, have an intrinsic significance and require close study.


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A single building may contain decorations from different epochs, and they must all be studied and valued equally.

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for documentary research, and documentary research determines the dating of structures. Together they give the building as a whole meaning and content. Research and the interpretation of documents, of all types, are always integrative.

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Graphic documentation is an important source of information. Jujol holdings. AHCOAC

The documents generated by the actions of the agents have always been considered the classical documentary source for historical knowledge.

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Exceptionally, artistic work produced to commemorate the construction of a house can provide valuable information. Transcription: “In 1631 Al-Haj Muhammad, son of the late Haj Jalim, son of the late Al-Haj Tamoun, constructed this house. It is situated near the mosque of Ibn Toloum. The house was finally transferred to a lady from the island of Crete, and this house shall therefore be called ‘Bayt al-Kritiliyya’”.


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The building as a place of experience: oral sources In many traditional societies in the Mediterranean, the spoken word is a value associated with tradition, where knowledge is handed down orally from parents to children, from master to apprentice, etc. The same norms governing some communities are handed down from generation to generation, without the mediation of any written document, and it is also some of these societies that retain rituals associated with the occupation of space and with construction. Rituals of the occupation of space involving animal sacrifice have continued to be carried out in some places until the present day. The assessment of oral sources has traditionally been the domain of ethnography and is vital in geographical and cultural contexts where, due to different circumstances, there has never been a tradition of generating textual documentation. Oral sources, in any case, are highly subjective and have to be submitted to a rigorous process of comparison and contrast and a critical analysis to ensure their validity, essentially no different to the process applied to other documentary evidence. Any historian knows that the only hierarchy of source is availability, significance and eloquence for each historical event, and that types of sources require a sense of criticism and self-criticism to interpret the precise content. Summing up The novelty of an approach of these characteristics to traditional Mediterranean architecture means that it lacks, to some extent, the necessary tools for correct historical interpretation. It requires a typological systematization of the construction techniques historically used in each place and time, the application of techniques of archaeology of the subsoil and vertical archaeology in the analysis of structures and walls, listing and inventory of the more relevant graphic and textual documentary sources, and ethnographic studies of the perception and memory of buildings and the construction process, as well as generalizing this type of historical interpretation to existing buildings before carrying out the rehabilitation project. It is also necessary to establish general schemes to facilitate the concretion of building techniques and historical and cultural contexts. To summarize, the historical study gives content and precise value to each building, based on a study of facts and contexts, arranged into a sequence, which explain the evolutionary specificity and constructional configuration. It is neither a story nor nostalgia, because it sees historical or traditional architecture not as a fossil of the past but as something that forms part of the structures and landscapes of our present. It is not intrinsically about the past, because the past is merely its means, not its end, and it therefore analyses part of reality from the chronological perspective that brings together the contributions of agents, factors and specific, complex contexts. It does not seek, essentially, to establish what a

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The spoken word is a value associated with tradition which allows knowledge to be passed down through the generations and transactions to take place without the mediation of written documentation, with houses being sold and works being contracted orally.

Rituals are carried out to cover the occupation of space and its preservation, using all kinds of amulets to ward off bad luck.

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house used to be like, but to explain, on the basis of periods of time, precisely why it is as it is. The analysis of a building involves knowledge of its structures from the viewpoint of architectural description, but also of when, how and why they are as they are. It contributes knowledge of the structure and its evolution, and has to be a useful tool for the subsequent rehabilitation work.

It is vital to know about the evolution of buildings throughout their history before undertaking a rehabilitation project. Traditional architecture has for centuries maintained its process of gradual growth by means of successive interventions. Knowledge of them is the basis for respectful intervention. The Torre del Fang: growth and transformations over seven centuries. Photographs: 1 (1890); 2 (1920), 3 and 4 (2006).

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It is interesting to consult the prologue by CHARLES-DOMINIQUE to Voyageurs arabes. Ibn Fadlan, Ibn Jubayr, Ibn Battuta et un auteur anonyme. Lonrai: Gallimard, 1995.

2 LAISSUS, Yves (ed.): Les savants en Egypte. Muséum National d’Histoire Naturelle. NATHAN, Paris, 1998. 3 His extensive body of work includes Las Cartas del viaje de Asturias o Cartas a Ponz (1782-1792), in which he explains with absolute precision the social and economic situation of this region. 4 Les loix des bâtimens suivant la coutume de Paris : traitant de ce qui concerne les servitudes réelles, les rapports des jurés experts, les réparations locatives, douairières, usufruitières, bénéficiales. Manuscript dated 1787. BNF.


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Tool 3 Overall knowledge of the building

Archaeology as a tool for finding out about the building

Before drafting the rehabilitation project for a building, it is necessary to have comprehensive knowledge of its history and elements in order to form a complete picture: its successive phases, evolution in time, the changes undergone and the causes for them. Only after discovering these things is it possible to decide how to proceed in the rehabilitation process: which elements to keep, restore or highlight, and which to demolish. In this way, it is possible share with others the sometimes thrilling history hidden in the walls and the subsoil of the building. In order to make the building “speak�, we first have to get to know it. There are various ways of achieving this, all based on research, with recourse to other disciplines beyond the specific field of the architect: history and archaeology. Archaeology is a science that detects, examines and analyses material evidence. Removing the earth to reach human vestiges, studying and documenting their successive phases, reading the history of humankind amid the interposed, interwoven traces of people and their works is the task of archaeology. Its revealing role imposes two successive stages: inspection of the surface and indepth research. It too has recourse to other exact sciences: chemistry, anthropology and botany. The archaeological method follows the method of the exact sciences. It is, then, based on the meticulous observation and analysis of the object with a view to reaching the cause of its origin. This is why archaeology can also be applied to building rehabilitation, since this too is a case that requires observation and analysis as a preliminary to knowledge. Like archaeological sites, a building is a silent witness to itself, that knows how to keep secrets hidden in its walls: its built elements, materials and even its subsoil all bear witness to its history. It is, then, necessary to examine these elements well, one by one, and, if necessary, to remove some of them to reach others that they may, in turn, conceal. If classical archaeology proceeds downwards, the archaeology involved in interpreting a building proceeds upwards. The application of the archaeological method to find out about a building is relatively straightforward; it involves proceeding by stages that may anticipate or follow the graphic plan and may even continue during the initial stages of work. In this case, it is necessary to complete the graphic documentation and consider changes to the initial programme if previously unknown elements revealed during the archaeological examination so require. I. Inspecting the site. Cleaning. First, it is necessary to examine the building, inside and outside, and distinguish the elements to

I. Knowledge

Evi Fiouri Archaeologist Department of Antiquities of Cyprus

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The remains of a medieval convent uncovered by a recent excavation beside an early 20th-century building in the old town of Nicosia

be removed immediately to enable a clearer view: rubbish, wild vegetation, earth piled up or dumped on the floors of courtyards and gardens. It is impossible to conduct a detailed inspection of a building if the ground is concealed by earth and the walls are half hidden by plants. II. Observing the masonry. The wall as a document: the wall is often a palimpsest on which we can read the history of the building and its evolution in time. In order to do this, we have to attentively examine several elements: materials, construction techniques, the bonding of the walls and all construction elements present, whether visible or hidden (windows, doors, decorations, etc.). Observing the construction materials. There may be different materials in the same wall corresponding to different phases. Careful examination will inform us whether these materials were used for repairs, to enlarge a space or to divide it into smaller rooms. Knowledge of the most used materials in a given period will help us to date the phases. These modifications are visible in bare masonry, but interiors are usually concealed by renderings that hide the proof of the different stages. In Cyprus, renderings are usually spoiled by damp and have to be replaced. During the task of removing them, it is possible to see all manner of modifications to the masonry, such as bricked up openings or the creation of smaller spaces. If the renderings are in good condition, they should not be removed. Careful observation can detect the

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outlines of arches and bricked-up openings beneath the rendering, which need only be removed from this specific place in order to show the opening and rehabilitate it. In important or delicate cases, thermography, endoscopy or other non-destructive tests may be applied. It is difficult to date masonry in itself, because Cypriot masons have used more or less the same construction techniques for centuries. This calls for an examination of the mortar used as bonding. The components of the mortar may help to date the masonry approximately. If it is not possible to identify the mortar by organoleptic means, it can be sent to a laboratory for testing. All of this information must be documented to complete the plan and obtain the clearest possible image of the phases of evolution and their associated modifications. Observing construction techniques. Walls built using a single material, such as stone, are not homogeneous to the eye. This irregularity is due to different construction techniques. A wall may include a different section representing a later phase, such as an upward extension to replace a flat roof with a ridge roof. Some construction techniques can be dated to a precise period and this is of great assistance in understanding the phases of the building. Walls on the lower levels may often be more modern than those higher up due to changes made at any point in the building; as far as walls are concerned, there is no vertical stratigraphy. Observing the renderings. The renderings of a building do not necessarily belong to the same period. Further, the renderings and their application technique may vary according to the use of the rooms, a factor that must always be taken into consideration. Knowledge of the period when a given rendering material was introduced into the country therefore helps to date the building or its historical phases. In Cyprus, there are four easily identifiable types of renderings used for dwellings: earth, earth mixed with chopped straw, lime and plaster, the most recent. There is also whitewash, either on its own or mixed with a colorant, such as indigo. The walls of rural houses may present successive coats of rendering; they may be of the same type or different, such as an earth and straw rendering beneath plaster, a material that was considered to be noble and rarely used before the early 20th century. An observation of renderings should not be limited to material alone. The frequency of application is another factor. An apparently uniform rendering may actually comprise several successive coats, as in the case of the whitewash that the occupants applied to the walls every year before Easter. The technique used to apply the rendering must also be taken into account. In urban homes, plaster is applied using screeds to obtain completely even surfaces, whereas in rural houses, the rendering is applied freely, following the irregularities of the wall. The architect has to recognise this difference in renderings and apply them accordingly.

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Detecting the renderings. Sometimes the walls give the impression of never having been rendered, though this is not always the case. A careful examination of the masonry may reveal traces of rendering in a corner, at the top of the wall, protected by the projection of the roof or remaining in the gaps between the stones. Sometimes it is enough to observe the technique used to build the wall in order to deduce that it was originally rendered: stone masonry built to be rendered (with plaster, for example) is not very neatly constructed because it is not meant to be visible and is made irregular to allow the rendering to take more easily. It is also necessary to observe the general style of the building and

Excavation on the site of a large 18th-century townhouse in Nicosia revealed two superposed floors dating from different periods (18th and 19th centuries)

The wall of a medieval manor near Nicosia presents the original masonry of dressed stone reddened by a 15th-century fire recorded by chroniclers of the time and the rubble and adobe construction of the Ottoman period


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individual architectural elements (frames of dressed or carved stone around door and window openings, projecting timber frames) to understand whether now bare walls have always been so or whether their covering was later destroyed or removed. The case of Lefkara, a village where elements of urban architecture were introduced by people who made their wealth from selling embroidery, is characteristic. The fashion of bare stone led to the general removal of renderings from houses that had hitherto stood out for their plastered and painted façades, a sign of wealth at the start of the century.

The walls of this rural dwelling comprise successive layers of different coloured lime wash

The arched opening of this watermill in the mountainous region of Troodos was built using dressed stone that suggests a meticulously sculpted decor belonging to a far more important building, probably the entrance to a church

I. Knowledge

Examining the joints of the walls. In Cyprus, most of the houses built using traditional architecture grew with the family and its needs, occupations and economic possibilities. The original cell is very often the makrinari or a dichoro, a single room of varying size, to which others were gradually added, first on the ground floor and then the first. This procedure can be seen at the point where the walls meet, showing the original wall against which another was later built. In this case, the walls are not joined together, and this can be seen if the walls are not rendered. This lack of ties often leads to the walls separating. III. Investigating the floors. Very often, the floor that is immediately visible in a building is in fact neither the first nor the only floor. Fashions, improvements in the owners’ economic situation and the changing uses of rooms throughout a building’s life are reasons for changes in the floor. It is, then, necessary to remove the most recent concrete, timber or tiled floor to find the local marble or pebble paving, or even the simple beaten-earth floor that was there when the building was constructed. These earlier floors have often been destroyed. We have to proceed with caution when removing the more recent floors in order not to destroy the sometimes barely perceptible evidence of earlier layers. Little may remain of an old floor but a few fragments of marble and their plaster beddings. For an architect who is familiar with the technique used to lay this kind of floor, these scanty vestiges are enough to understand and rehabilitate the type of original floor. Each layer corresponds to a phase in the building’s evolution; each must be graphically documented to reflect which level is to be conserved and, if possible, show the previous layers in evocative fashion. Not all the layers can be used, but neither should they be destroyed. The oldest levels must be preserved, once duly documented. The result is a complete plan that tells us graphically about the history of the building. On sites with a long history of human habitation, it is even useful to carry out investigative sections in order to detect floors that are older than the existing construction, and document them graphically and photographically. Likewise, in a courtyard we have to look for the paving, the well and the drainage system by means of a carefully conducted cleaning process, a kind of mini-excavation after prior inspection. Investigating thresholds and foundations. Often it is not possible to see the original floor level. In this case, the search will start at the door to find the threshold, the point where the interior floor comes to an end. Sections can also be made along the walls to examine their foundations, which sometimes turn out to be the walls of older constructions. Excavations. Most excavations of the basements of traditional architecture buildings are the result of chance findings of archaeological remains when digging to install waste pipes or to

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Tool 3 Overall knowledge of the building Archaeology as a tool for finding out about the building

reinforce the foundations. On those sites where human presence dates back millennia, these finds can be frequent. There are houses where ancient tombs or the remains of walls dating from much earlier periods have been discovered in the basement. Nicosia, the capital of Cyprus, is a characteristic example. Inhabited for thousands of years, the present-day city stands on successive layers of habitation, dating back to the Chalcolithic age. In particular, the walled old town of Nicosia, capital of Cyprus since the Byzantine epoch, an opulent town in the Middle Ages, conceals beneath its modern surface countless vestiges of its Palaeo-Christian and medieval past. The Department of Antiquities has declared the entire city sector that stands within the Venetian walls an Ancient Monument. Since then, all construction work has been monitored to prevent the destruction of archaeological remains. According to the new law, a special permit from the Department of Antiquities is needed for any new construction operation or work in existing buildings that requires excavation. In the case of new constructions, the Department undertakes partial excavations on the site or is present at the excavation of the foundations and stops them if archaeological remains are uncovered. In this way, important remains have been discovered in several places, and systematic excavations conducted. Important archaeological remains are conserved. This may be something of a constraint on development, but now Nicosia, as the capital Lefkosia has been called since Frankish times, has started to gain a better knowledge of its past. In the same house in Lefkara, the difference in renders between rooms suggests different phases in the history of the building: the whitewashed, uneven earth rendering pre-dates the 20th century, whereas the gypsum plastering with its perfectly smooth, even surface could easily date from the early 20th century.

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Applying the archaeological method to Lebanese architecture

Intimately linked with its historical origins in the context of memory stretching back thousands of years, traditional architecture in Lebanon is characterized by its close integration with the territory and its adaptation to local resources. Typically Mediterranean in its materials, forms and colours, the Lebanese vernacular habitat dots landscapes as varied as the coast, the plains amid mountain chains and even the high inland plateaus. Whether rural or urban, these traditional houses are a melting pot of the collective memory and serve to anchor nostalgias and identities. Poorly treated, destroyed and often abandoned, it is with great difficulty that the traditional house has survived the vicissitudes of the times and changes in lifestyles. In those cases when it is not completely transformed or recovered, it is the object of many interventions in which in-depth knowledge of their construction is often lacking. Recent rehabilitation projects in the Lebanon are however starting to apply similar methods to that of the archaeology of the building. This relatively recent branch of archaeological science is generally applied to listed historical monuments with a view to developing an upward reading of chronological indices, fundamental elements in a stratigraphic analysis. The building studied is, then, analysed as an element of material culture in its own right. Traditional architecture essentially belongs to a pre-industrial world. Its evolution with society and the numerous modifications it undergoes to adapt to the needs and the new means available to each age make it an excellent support that bears the traces of these transformations. The aim of this analysis is mainly to implement a relative chronology of the architectural object and its life in a historical context. A concern for comparative typology completes this approach, along with potential research into the techniques implemented in the building. This methodological interpretation of the built work contributes to a better rehabilitation project. The so-called archaeological approach is essentially based on the collection of data that serves as a support to develop analyses on the following themes: - The evolution of the building as recorded in documentary sources - The evolution of the building in terms of its physical interpretation by means of stratigraphic analysis. The stratigraphic process refers by definition to a study of chronologically sealed layers, from the lowest to the highest,

I. Knowledge

Yasmine Makaroun Bou Assaf Architect and archaeologist Expert consultant to the ICCROM for the ATHAR project, Lebanon

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Preliminary visual plan (DebbanĂŠ house, Salhiyeh)

according to the laws of gravity. This method is not limited to the diachronic aspect of the succession of layers, seeking above all to integrate the ethnographic aspect of occupation. Unlike an archaeological excavation, the sequences are read in elevation, by construction or intervention phase, rather than by the accumulation of strata. The historical study has recourse to various registers in order to interpret these transformations and restore the configuration of the different stages in the life of the building: Morphology Architectural typology Construction materials Built structures Coatings and renderings used

Sampling the construction materials (DebbanĂŠ palace, Saida)

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Tool 3 Overall knowledge of the building Applying the archaeological method to Lebanese architecture

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Map of disorders (Debbané palace, Saida)

The information needed to carry out these analyses will be obtained by various means: Document collection, directly or indirectly related to the object of study: administrative, cadastral, property and photographic documents, newspaper articles, publications and correspondence Oral sources, drawing on the occupants’ memories Written sources (administrative documents, correspondence, publications, etc.) Iconographic sources (drawings, paintings, photos, etc.) A preliminary plan provides the basis for reconnaissance at the global scale of the building: based on a visual examination, it must quickly be transcribed in a summary graphic form (sketch) and photographs. A detailed, targeted plan enables more in-depth research and delimitation of the building’s specificities: it will be primarily graphic and metric as the basis for all the necessary supports (plans, sections and elevations). This graphic support at scale serves to record all the visual observations made in every nook and cranny, completed by photographs. These observations must however be methodical and differentiate the themes in question (materials, claddings, pigments, disorders, etc.). It is in this approach, particularly in the elevations, that the interpretation and collection of data coincide most with the stratigraphic method. The vertical dimension of the construction phases will be worked on the basis of detailed sections and elevations. Surveys, judiciously located on the basis of the definition of a specific problem will reveal intermediate supports and potential

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connections that are not visible to the naked eye. Surveys are vital to an understanding of built work and are used very discerningly due to their destructive approach. The material (constructional or domestic) collected by these surveys contributes to an understanding of the problem raised. Samples are used to carry out visual or laboratory analyses (fig. 06) of the materials or supports with a view to defining their components and proportions. The analysis of samples backs up visual observations by providing precise, tangible support. The information gathered about construction techniques used in the traditional building can be compared with other, similar studies in the framework of a multidisciplinary approach. This approach, often regarded as long and tedious, has the advantage of providing exhaustive information about a form of architecture mistakenly classified as primitive. Generally applied exclusively to monumental and historical constructions, the archaeological method helps to promote the vernacular building to the status of architecture that is “worthy of interest”. The information gathered in this way serves as the basis for a varied database, a comprehensive form of documentation of this disappearing architecture.


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I. Knowledge

A comprehensive understanding of the building

José Luis González Moreno-Navarro Doctor of Architecture Professor of the Department of Architectural Technology I, School of Architecture of Barcelona (Technical University of Catalonia), Spain

Some preliminary issues about the method

existing building, and the method should be the same, though adapted to the case: the scientific method. There is no need to shy away from this term, because the scientific method is no different to the rational attitude of everyday life or other fields of human knowledge. Historians, detectives and even plumbers—all human beings, in fact—use the same basic means as physicists or biochemists when trying to solve a problem or answer a question.

The aim of this text is to assist anyone who has to rehabilitate traditional Mediterranean architecture in the essential process of knowledge and understanding that must precede any decisions as to intervention. A simple way of establishing the concept of knowledge is to define it as the capacity to answer different questions: What is it? What is it like? What is it made of? They all share the aim of describing the object in question, both the obvious and, particularly, the not so apparent. If we answer some of these questions, we have established what we know. However, it is very probable that we do not understand it. At least, we can say that understanding does not derive directly from knowledge in itself. In order to understand, we have to be able to answer a different key question: Why? The reason for all the above: why is it like it is, why is it made of what it is made of, and so on. If we take action on heritage that is distinguished as the consequence of an intense historical evolution, the aim of knowledge has to be broadened to what it was like or how it evolved from a given state to its present state. As regards the “why”, we have to establish why it was initially like it was, why it has evolved in a way that has made it like it is, etc. We have to be aware that this is an activity in which neither architects nor engineers are trained, for a very simple reason. Our training is technical—our aims mainly involve designing artefacts according to a process in which the artefact comes first in our minds and, then, by means of the protocols of industrial or constructional production, we make it reality. When we are faced with an existing building, the situation is very different. We are facing an artefact that already exists and that is not in our minds. Knowledge and understanding of it necessarily require a different method to the one applied in the design of artefacts. Furthermore, if a historical building is constructed using means and mentalities that are practically unknown to us, the difficulty increases by several degrees. In this situation, the method should be similar to that of disciplines in which the principal objective is to know and understand something external to ourselves, like the scientific disciplines that seek to understand our environment. Biologists, astronomers and geologists do not design the objects of their study; they try to understand them. This is what we should do when faced with an

The reason why It is a question of following the five basic phases of the scientific method: Tabling the problem or question requiring an answer Formulating a hypothesis that temporarily provides the solution or answer Organizing proof or observations to verify it Developing the proof or observations, and Checking the applicability of the supposition embodied in the hypothesis. In order to be efficient in our work, it is very important for the initial hypothesis to be as close as possible to the reality we are aiming to discover. This will depend largely on our prior knowledge of possible answers to the questions. The general lack of knowledge of historical construction is undoubtedly a great hindrance to this process. This text aims to facilitate this process of interrogation and the search for answers, especially with regard to historical construction, bringing to bear a series of basic “whats” and “whys” with a high degree of certainty. In each case, more questions must be added and more answers found by formulating explanatory hypotheses which, on many occasions, it may be impossible to compare and contrast. In general, things produced by technical activity are the result of a fundamental fact: the object in question has to have a value in the environment in which it is produced and this value, when speaking of buildings, is its utility or, more generally, its purpose. One way to find answers to the question why is to pinpoint the purpose that brought the object into being and the means that made it possible. As in many other areas, it is a problem of ends and means. However, if a rigorous study of any kind of object is difficult, one

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about something as complex as traditional Mediterranean architecture may seem insurmountable. An overview of this enormous diversity (which can be found in the splendid book Traditional Mediterranean Architecture) suggests that there are features common to all cases, allowing us to find a common explanation (even if it is masked by the features deriving from this enormous diversity). In this article, I set out to find the common elements shared by all cases and the variables in diversity. To begin, we could say that the essential purpose of buildings is not the only common denominator; there are also facts that affect every site, such as something as obvious as the action of gravity, which is perpendicular to the plane of the site—i.e. vertical. As regards diversity, this emerges both from the means and from the end as the result of the variations encountered in different places, not just from the viewpoint of climate, an important factor in diversity, but also with regard to the resources available and the cultures that harness them, which also change with time. In order to address all of these points, I will follow the method we use when teaching at the Barcelona School of Architecture.

Points in common The end result of any building is always the consequence of a synergetic sum of decisions made about various constructional elements that respond simultaneously to different ends. It is the consequence of a more or less conscious, reflective process of synthesis of various factors. It is a process that does not respond to a single pattern and which is, therefore, different in each case and every place. A study of the building requires these ends and means to be broken down into parts to be analysed in isolation. The success of the operation depends largely on the extent to which this breakdown is representative of reality. According to the above-mentioned teaching method, any element in a building is, largely, the consequence of the need for: A space delimited by a built material form that is stable from the very start A production method that is as efficient as possible A construction that is as long lasting as possible with the aid of suitable maintenance Improvement of the natural environment Satisfaction, on the part of the forms and materials, of the desire for beauty that all peoples, however simple, owe to their human condition. Let us take each of these principles separately. The analysis of any construction shows that the aim is to create a

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space that is different to the natural space, in most cases by using vertical elements that support other elements added to them at a slope, horizontally or in the form of an arch. These elongated vertical, horizontal or arched forms have to be constructible and only exist in the imagination of the builder if they have been built before—that is, they are not imagined forms of which there is no experience. However, any act of construction, as we all know from a very young age, comes up against a major difficulty: gravity. If the elements are not judiciously positioned, they will fall down, so this constructible form has to be stable from the very start. This essential issue marks the existence of all masonry buildings though it does not explain them entirely, which leads us to the following variables. Behind any popular building there is a scarcity of resources requiring the builder to apply his ingenuity to production efficiency; any solution has to be applied with the maximum of benefits and the minimum physical effort not only for the builder but also for the population in general as regards the extraction and stockpiling of materials. Almost all traditional Mediterranean houses are built of materials available near the building site and based on constructible forms that are stable from the very start. Nonetheless, time passes, it is windy, it rains, is hot or cold, and what initially solved a series of problems loses its initial form or some of its materials and begins to deteriorate. To prevent this happening, the builder tries to find out what has failed and comes up with a new way of making the construction longer lasting. He also identifies the periodical care it requires. This is the principle of long-term integrity. The result of applying this principle is a well built, lasting space, but this is still insufficient, because it also has to provide the occupants with a comfortable habitat. The basic reason for building a dwelling is in fact to adapt the environment. Throughout history, peoples have sought to improve external environmental conditions: to protect themselves from the rain and damp ground; from excessive heat or cold; from too bright a light, etc. If we follow the methods required by these points, we will have an adapted, efficiently produced space that lasts a long time. But nor is that enough; the dwelling also has to produce a pleasing visual landscape, of which we are proud and that serves to say who we are. The textures, colours, patterns and forms we see, apart from solving practical problems, have to be in keeping with our visual and symbolic culture. This is what we call aesthetic convenience. If we manage to achieve all of these ends, we have produced architecture, and it is quite safe to say that any artefact belonging to the field defined as traditional Mediterranean architecture can be explained by these five ends. To focus on the most usual case, settled construction (leaving nomadic constructions for another moment), the exterior is always


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separated from the interior space by a series of elements that we might call the envelope. It comprises vertical elements, façades built almost always with walls and elements that close the top of the construction, which we will refer to as horizontal, though its lines may not strictly that: flat or sloping roofs and, in quite a few cases, domes. The envelope is the essential element that provides the solution to almost all requirements—space, environment and aesthetic convenience—and is subject to the main agents of deterioration. It will provide the focus for a study of diversity.

The diverse Having defined the common elements, it is necessary to establish criteria for addressing diversity. There is no point here in producing a list of the existing places, climates and material resources in the

I. Knowledge

Mediterranean basin. The point is to address the consequences of diversity, which are the means to meeting those ends which also respond to a series of ends specified by the place—that is, the elements used to construct the building. As the first step on this path, I will examine the most representative element of the envelope: the wall. The wall The wall responds to various practical requirements such as the need for stability from the very start, maximum duration and separation of the exterior from the interior. It also has to be seen as a fundamental element in the symbolic, aesthetic support of the building. In form, it is a parallelepiped with its long sides (length) and short sides (depth) perpendicular to each other and parallel to the ground; the third dimension, height, is situated vertically. This form is the result of its role in shaping the space and, at the same time, as we all learned when we were very small, it is also the best way to build a stable vertical element that stands up to the immediate action on it of gravity. The long dimension is defined by the building’s floor plan; the intermediate dimension, or height, is defined by the height of the space we hope to achieve, and the third dimension, the depth, which is key to structural behaviour, is conditioned by the demands of stability and the material or construction procedure used to build it. Diversity is the consequence of finding the different responses that a wall can provide to the ends listed above: stability from the very start in order to create the space, adaptation to the place from the viewpoint of available materials and techniques (rammed earth, brick, stone, etc.). A common factor in all walls is the fact that they are the result of the means available near the place as regards materials and efficient means with regard to the techniques of execution. But there would be no point in a wall unless, while separating us from the exterior, it allowed us to communicate with it by means of something as obvious as the openings that enable us to enter and exit, see out and in, and renew the air that we breathe. There is no point in talking of walls without openings or in considering that openings weaken the wall. There are no walls without openings; the openings are the wall and the wall is the openings. The key element in the opening is the upper element that transfers the weight of the wall above onto the two sides of the opening or the jambs. This is usually a lintel, generally made of timber, or a segmental arch built using the same material as the rest of the wall. Nor must we forget the vertical elements that delimit porches or semi-exterior spaces: columns or props. Their dimensions depend on the horizontal elements used to organize the porch, be they straight-lined or arched.

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At the same time, all together, blind wall and openings, it has to be long-lasting and the answer is obviously very different if there are suitable stones on site to make ashlars that can be left visible or if there is only earth to make a rammed-earth wall. One of the most frequent causes of degradation is water, either from above in the form of rain or from below by capillary action. If a homogeneous material such as rammed earth is used, the whole thickness is built of the same material. If it is built of small elements, such as brick or rough stone, depending on the relation between the size of each unit and the total thickness, two or three withes will be needed. In either case, these two or three withes must be perfectly connected, otherwise they may act independently, generating a high risk of sagging. If the material is vulnerable, it has to be protected by an outer facing to limit deterioration due to contact with the elements. This facing also has to meet the needs of beauty and identity. It is important to remember that the wall in question has stood there for a long time since its construction; the wall, and any element in the building, is an extraordinarily valuable document for revealing its own history. Changes, additions, degradation and repairs all go to constitute a document that can help us towards the key factor that is an understanding of its history. However, the elements in which we find greatest diversity are those that subdivide the space horizontally.

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Horizontal elements The major difficulty in constructing a building arises when it comes to the elements that subdivide the space horizontally or close it at the top. While the vertical wall works in favour of gravity, the horizontal elements by definition defy gravity. A wall rarely falls (due perhaps to seismic movement), but a poorly supported horizontal element will invariably fall, or, if excessively compromised, it will buckle and break, something that rarely occurs in a wall. This difficulty, given the diversity of histories, environments and techniques, has generated a rich catalogue of solutions based on two key elements: timber materials, which due to their genetic origin are resistant to bending, and the inventiveness of the human constructor when timber is scarce: the arch, the vault and the dome. Of all of these elements, the one with a special role in the exterior image of the building is the one that closes the top. The roof may be sloping, vaulted or domed. It is normally a key element in the aesthetic and symbolic expression of the whole. In most cases, the vertical subdivision of the interior space generated by the walls and the upper facing or roof comprises plant materials, generally tree trunks, which are characteristically resistant to traction and compression, and, as a result, bending. The applications in the face of the two demands on these elements—strength and resistance to bending—depend on the


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form (the span covered and the edge or vertical dimension) and the material, resistance to traction and rigidness. In general, long rectilinear elements that can bridge a total span are costly, so, to reduce the number needed, they are combined with smaller elements that bridge the span between two main rectilinear elements. The unit they produce together is the floor. The elements that bridge the span in the roof element are normally sloping beams which do not form a triangular framework structure due to the difficulty of tying the different elements. In general, we find a main beam on which a short prop supports two sloping beams, each bridging half the span and generating the slopes of the roof. In places where the atmosphere is drier there are flat roofs which, in static terms, are the same as the floors, though subjected to greater loads due to the material that has to be added to them in the form of not totally impermeable layers in order to make the whole impermeable. Nonetheless, the elements to have represented the greatest invention on the part of their builders—and the greatest admiration and number of unanswered questions today, in view of their disappearance from academic teaching—are those that describe a curve: arches, vaults and domes. Arches can generally be built in one of three ways: with dressed stone voussoirs; with rougher pieces of stone, or with bricks laid to follow the radius of the arch circumference, bonded with mortar. The mortar bond in the two latter cases provides the different thicknesses in the intrados and extrados to achieve the curve. To understand an arch, it is necessary to consider two key points:

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There is an important tradition in much of the Mediterranean basin of building a kind of vault that is known by different names according to the place. In the maó de pla, in foglio or even Saracen vault, the bricks were laid parallel to the intrados. It became widespread due to the presence of Catalan builders throughout Spain, France and the Americas, and is therefore also known as the Catalan vault, volta a la catalana or voûte catalane. It requires as least two layers of bricks, the first being bonded with plaster, as this removes the basic need to construct any kind of centring, which is not needed in the Catalan vault.

Its construction requires a provisional auxiliary element, the centring, the characteristics of which will depend on the type of masonry and the specific techniques of each place; In all cases, the arch generates forces of thrust and drift that tend to open up towards the abutment or spring. In order to be completely stable from the very start, the arch requires the abutments or springs to hold their shape, so they have to be a certain width. Historically, builders developed simple rules that relate the span of the arch with the width of the abutment. If it is an arcade in which the arches rest symmetrically on the impost of a pillar, the thrusts cancel each other out and only generate a vertical weight, unlike the case of the arches at the two edges, which require a broader prop. Like arches, vaults may be built of perfectly dressed voussoirs, though this is rare due to the difficulty of the task; stone masonry using relatively flat units, similar to bricks, and different thicknesses of mortar to produce the curvature, or orders of bricks.

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Many techniques have been developed to reduce to a minimum the need for provisional support for the vault. In those cases where the bricks are laid on edge, work begins at the corners, etc. All of this can be analysed by observing the bonding of the intrados. In all cases, they generate forces of thrust or drift on their supports, which therefore have to be thicker than the walls that only support floors. As in the case of the arch, it is important to be familiar with the rule followed by builders since time immemorial, by accumulation of empirical knowledge, relating the form of the vault, the span it covers and the corresponding thickness of the wall that provides its stability. For example, a rule applied to the construction of barrel vaults in the 17th century in Spain advised that the thickness of the wall should be a third of its span. It is reasonable to suppose that all traditional builders have similar rules that have been handed down from master to apprentice, knowledge of which is vital in each case. All of the above considerations can be applied to domes, with the addition of a further, very important one. When working with circular or nearly circular floor plans, it is possible to establish a system that balances out thrusting by using a tension ring that reduces these thrusts to zero. In consequence, the dome only transfers vertical loads, with a very noticeable reduction in the thickness of the walls. The building Finally, we come to the building as a whole. The construction of the building requires the builder to understand the relation between all of the elements. The same understanding is necessary for the agent intending to rehabilitate the building. The building is generated by the interrelation of space and the elements that delimit it. The dimensions of the space are conditioned by the possibilities of these elements. If no large trees are available, it will be difficult to build large separations between the walls. If there are no trees at all, it will have to be built using vaults that require thicker walls, etc. Though space is defined by the initial end of housing a function, it is limited or favoured by material and technical resources.

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It is also vital to understand the relation between the different elements. In the case of walls, for example, the fact that one is joined to another by means of a well connected angle allows it to be much more slender than a freestanding wall, as well as being far more stable in the event of horizontal thrust. Therefore a key issue in the behaviour of buildings with walls is the need to create bracing walls, forming angles or T-joints. Ultimately, stability can only be understood as that of all the walls together. This takes us to the final variable to be taken into account as regards long-term duration. In areas where there is no seismic activity, the only factors that can reduce the building’s stability over the years, as explained above, are an increase in load, a reduction in thickness or material degradation. In places where seismic activity is noticeable, however, it must be taken into account. It is therefore vital to understand the overall behaviour of all elements. A freestanding wall that receives a seismic movement perpendicular to its face will easily fall. If that same wall has a further two built perpendicular to it, forming a U-shape, it will remain perfectly stable throughout even pronounced seismic activity. If seismic activity is very pronounced, the builders’ experience will prompt them to add more effective elements, such as iron bars to


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join facing walls. In other places, the strategy applied combines masonry with timber elements, producing very different behaviour to that of the solid wall. It is important in this overview not to forget that almost everything we see in the building is the consequence of the vast transformations that have taken place in general in the last century, particularly the implementation of installations. Most buildings are the consequence of variations and the addition of accessories produced in the 20th century in response to the need or desire to increase environmental and hygienic comfort and also, it must be said, as the result of mistakes caused by ignoring the history of buildings when renovating or adapting them to the times. One very forceful consequence of the 20th century was the implementation of installations, totally absent when most traditional buildings were constructed. The interrelation between their associated tubes and the historical support calls for a specific study, as an understanding of it is vital to the rehabilitation project. However, it must be based on the realization that we cannot refuse the contributions of the 20th and 21st centuries to the comfort and safety of the users of traditional architecture which has to continue to exist for centuries to come.

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The urban phenomenon This final stage in our examination of buildings moves beyond our scope and marks an end to this text: the grouping of buildings to form a village, town or city—the urban phenomenon. If we hope to understand the building, some of our questions must address the interrelations between all buildings or, conversely, the effect on buildings of the city or the urban fabric. In short, if we can reach an understanding of how they have come into being, and answer present-day questions, as well as those that are the product of the history and particularities of the place, the techniques, the resources, the culture and the people who live there, and, at the same time, of the whole, then we can say that we have a comprehensive understanding of the building.

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Architectural analysis of buildings. Typologies in Cyprus

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Restoring a traditional building is to know the local architecture and the traditional way of life. Only this way can one understand the typology, morphology and the building materials of the local dwelling. The simple life of the people connected with earth and nature is reflected on the simplicity of the traditional Cypriot house. The minimal needs of the family do not force the mason to look for complicated forms of houses. All that it needs is a shelter space under which the Cypriot family joins all their activities. The form of the house simply follows the construction without being influenced by the interior. An important factor in the formation of the traditional settlements in Cyprus was the variation in the landscape. On the plain areas the settlements consisted of a series of closely packed houses with flat roofs. A high wall surrounded each house thus leading to the formation of a yard. On the mountains, the houses were built attached to each other continuously and packed, exploiting as much space as possible, having tiled roof. The variety of Cyprus topography allowed the anonymous mason to provide splendid examples of housing complexes, avoiding monotony even when the facades are plane and simple. Important factors in the shaping of the house are the local materials and the experiences and skills of the mason. Local masons built houses without any architectural plans and with materials available from the surrounding area. The houses were constructed mainly from adobe and stone. The openings (doors and windows) are few (fig-

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Eliana Georgiou, Architect Technical Assistant in the Department of Antiquities, Cyprus

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1), and sometimes less in the side of the road. Rectangular or square small openings (arseres) were made for ventilation. The most popular simple traditional house is the platimetopo makrinari (fig-4). It consists of a rectangular covered space. As the various functions of the people increased and life became more complicated, bigger space was needed: The makrinari-dichoro was then created (fig-5). This was accomplished by joining two makrinari, using an arch. The new space allowed more comfort, movement and organization. At the same time, illiakos appeared (fig-6).

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Illiakos (fig-10) is a covered space formed in front of the house, which extends onto the full length of the south side of the dichoro. All the household activities are transferred in the illiakos. This is achieved, because the climate of Cyprus allows for it. The illiakos was an essential component of the house. The space was used for work, recreation and congregation- a direct connection with nature. The various spaces of the house were not built at the same time, but added according to the needs, the social and financial status of the owner. As the linear extensions, there were also extensions in the shape of “L” or “U” (fig-7) or in the upper floor because of the lack of space in small plots. The yard, surrounded by a wall, is the heart of the Cypriot traditional house. It plays a vital role in the daily life of the inhabitants, with all the activities taking place there (fig-9). In the cities, the house is the evolution of the rural traditional house, but more complex. The makrinari remains the basic space. The houses were built attached to each other in continuous and packed strips, lengthily positioned alongside the road. The orientation is according to the road. The illiakos–portio is still the axis of the house. It is the main entrance to the house, opening with an arch to the backyard. Sometimes, it is closed to give more inner space. In each side of it, symmetrically, two makrinaria are located. A second illiakos is made alongside the inner length of the house, supported by arches, in which stands the staircase for the upper floor (fig-2, fig3). This inner illiakos is repeated at the upper floor level. On the upper floor, above the road and the main entrance, the kioski (fig11) (in later times becomes a balcony) is an extension and connection with the outer world. The main entrance is built with great care; it is the element that

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gives the character to the urban house. Sometimes, above the door, a carved stone with figures is put. The small windows are replaced by bigger ones with stone frames, and having outer and inner shutters. The yard in the urban house is smaller and looses its role as a place of work becoming a garden with trees. Also it is important for someone to consider the internal decoration and furnishing of the traditional Cypriot house. We can see excellent pieces of folklore art, such as gypsum or wooden shelves, traditional weaving machines, wardrobes and cupboards as well as richly engraved chests (fig-17).

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Thermal comfort in existing homes

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Maria López Díaz, Architect Agence Nationale de l’Habitat (ANAH), France

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Introduction The purpose of buildings is to provide islands of comfort. They represent the protection that humankind seeks. They constitute barriers to rain, snow and wind; protection from the cold and, sometimes, subtle filters of light, noise and heat. This search for comfort is not new. Socrates taught the art of constructing a pleasant house according to orientation, sunlighting, the time of year and the configuration of the façade. However, demands have changed, becoming more stringent (I cannot say they have evolved), leaving to one side an integral conception of the building, seeking comfort to the detriment of natural resources. Today, a sustainable conception of building or renovation has to centre on passive means and efficient installations if it is to achieve its aim of producing comfortable housing using positive energy (which produces more energy than it consumes). In this respect, we can learn from our forebears, who used different techniques according to the climate: humidification, ventilation, insulation, etc. We can even learn from plants.

Small thick leaves present a small surface area to the cold and the air.

Learn comfort from plants? Plants obtain the comfort they need by means of suitable conception, form and position. Example: The high plateau starts at 3200 m and continues to a height of over 4600 m; it extends as far as Colombia and even Peru. Plants share similar characteristics of adaptation that allow them to live in this region with an extreme climate. Slow-growth plants can absorb the heat from the ground during the day Silvery pigmentation to reflect solar radiation, which is enormous at this altitude Small hairs on the leaves help to conserve heat and moisture by creating a barrier between the surface of the plant and the air. Small thick leaves present the smallest surface area to the cold and to the air in order to conserve heat and moisture, and also to the sun, in an almost vertical position.

Silvery pigmentation reflects solar radiation.

Hairs to conserve moisture content.

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Traditional architecture and comfort

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Traditional architecture takes into account the microclimate in order to achieve hygrothermal comfort for humans and for the building. Microclimate should determine the choice of site of the building, either to make the most of existing conditions or to evaluate the possibilities of correcting unfavourable conditions: by means of the actual construction, vegetation, surfaces of water, choice of materials, shape, size and arrangement of openings, etc. In this way, an improved microclimate is created in relation to the regional climate. But what exactly is comfort? Comfort for people at the scale of the town?; at the scale of buildings, their homes? The comfort of the building? Is comfort today the same as it was yesterday? And what about tomorrow? If we consult the dictionary, we find “notion of material wellbeing”—a difficult definition to relate to our sensations of cold or heat… If we go back to Old French to find the meaning, “comfort means assistance”.

“…It was called ‘well being’ in the late Middle Ages, ease or convenience just before the French Revolution. Comfort, in the sense that we now understand it, appeared in France in the industrial age, with a peculiarly British ‘m’, due to the reimportation of this originally French word” (Jean Pierre Goubert, Du luxe au comfort). In architecture, the term becomes more complex. Material comfort seems easier to express in relation to having access to a bathroom or toilet; the definition becomes more complicated when we speak of thermal comfort—or hygrothermal comfort when our sensations are in direct relation to the two inseparable parameters… We refer to the comfort of people, but also the comfort of the building. It is interesting to note that human comfort has points in common with the comfort of a building. For example, too high a level of humidity disrupts our balanced transpiration and can restrict breathing, but it can also be the cause of rot in some woods, of the growth of rot fungi, faster corrosion of metal elements, surface condensation on walls (particularly if poorly insulated) and heat bridges, and many other things besides. The internal temperature of our bodies is approximately 37°C. The built spaces that surround us are generally less hot. Hygrothermal comfort can be achieved provided our bodies lose heat at a suitable speed: if they lose heat too fast, we feel a sensation of cold, too slowly and we feel a sensation of heat.

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City comfort levels? With greater mineralization and the corresponding increase in thermal inertia, cities experience the heat island effect.

Green spaces on roof tops: landscaped roofs play an important role in comfort in cities, contributing to water evaporation, dust retention, thermal and acoustic comfort, and air quality.


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Can the same parameters be applied to comfort in the past, comfort today, comfort when on holiday and comfort at home? Humankind has always aspired to comfort, but the concept of comfort has changed throughout history, according to cultural models, technological “progress”, and even with circumstances. When we are on holiday, in the mountains, for example, “away from it all”, an ideal situation sought “just for a few days”, our appreciation of comfort is quite different to what we want at home in the city. That cold, damp, draughty hut actually seems comfortable. However, its temperature and humidity content are far from our usual comfort parameters. Not so long ago, in our grandmothers’ day, when we were cold in the house we would put on a thicker sweater, or even two. Today, even when the temperature drops, we walk around the house in T-shirts, and even the buses are heated! The last century was characterized by uncontrolled exploitation of our planet’s resources. Today, an awareness of dwindling resources presents us with the dilemma of how to maintain our comfort in a world without petrol, while conserving the ozone layer.

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The answer may be to change our behaviour, using new technologies and salvaging our forebears’ knowledge of building in harmony with the climate, using suitable materials and systems.

Hygrothermal comfort for people

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We seek comfort: not too cold, not too hot, no annoying draughts. In the same space, one person may feel comfortable while another feels uncomfortable. The appreciation of comfort depends on the individual, though by playing with essential parameters such as temperature, air movement and moisture levels, it is possible to obtain a balance that suits most people. Hygrothermal and respiratory comfort depend on various factors, including: The individual: His or her metabolism, The clothes he or she is wearing, What he or she is doing. Temperature and humidity The mean radiant temperature of a given wall or room The temperature of objects in contact with our bodies The movement of the air on and around our skin The human body seeks balance; it exchanges heat with the atmosphere by means of various transfer mechanisms: conduction, radiation, convection and evaporation. These exchanges take place by means of the respiratory tract and the skin. Reminder: Radiation The emission of infrared rays. As a result of this thermal energy, any object that is hotter than the surrounding bodies gives off heat to them. Thermal exchange takes place between the skin and the solid elements in the environment. Conduction Unlike radiation, conduction requires direct contact between the objects. It is the transfer of heat between objects that are directly in contact with each other. Convection Exchange between the body and a moving fluid, almost always air or water. The importance of convection can be considerably modified by exterior conditions.

Vegetation naturally reduces the heating of an opaque wall: pergola and lattice walls. Hence the interest of using deciduous plants to warm walls in winter and protect them in the summer.

The interaction between the objective data of the environment and the perception of human beings is a complex process.

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Variables associated with people

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How we dress. By adapting our clothing to the demands of comfort, we can adapt quickly to climatic variables not only outside the building but also inside. The values of thermal insulation of clothes are measured in clo, the clothing insulation unit that gives a person at rest a skin temperature of 33°C in radiant temperatures of 21 °C. 1 clo is equivalent to 0.16m2C/W of thermal resistance. With its irrational use of energy, humankind, particularly in developed countries and most particularly in large cities, has forgotten the role of clothing in thermal comfort and energy saving, and, therefore, the protection of the environment. Today, when we are cold, we turn up the heating and when we are suddenly too hot, instead of turning down the heating we open the window. In the dog days of summer, we forget to close the shutters (if we are lucky enough to have conserved them) and open the windows instead of closing them when the air temperature is higher outside the building than inside it. Our behaviour is vital to obtaining comfort at the lowest cost to the environment. Our grandparents had recourse to some great cutting-edge technology with aesthetic variations, in the size and colours of their choice, representing a low initial outlay, within reach of all budgets, requiring low maintenance, and the lowest return rate: the sweater! A light, short-sleeved sweater, 0.17 clo, a thick, longsleeved pullover, 0.37 clo! Metabolic energy (Watt/m2 of body surface) and work: the production of metabolic energy depends mainly on type of activity and position. The sensation of comfort varies according to our body’s heat production and heat loss through the surface of our body. Levels of activity, work: according to one’s level of activity, the body has different needs and reactions. A person at rest, sleeping for example: 41 W/m?. A person walking up a steep slope or stairs, 260 w/m2. The body’s capacity to adapt to different climatic conditions: principally in relation to heat: transpiration, increase of blood circulation on the outer layers of the body in order to increase heat loss, change in breathing. Comfort: difficult balance between temperature and moisture: The balance between air temperature (dry-bulb temperature) and the relative humidity of the air (quantity of water vapour contained in the air), always measured inside the building, are vital data for measuring hygrothermal comfort.

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The bioclimatic diagrams indicate the comfort variables as regards humidity and temperature. What interests us is the relation or balance between temperature and moisture, as shown in the diagram below: If the hygrometry of the air is high in relation to the air temperature, the evaporation of sweat is slowed, preventing the body from adapting to the climate, and prompting us to speak of discomfort.

a) b) c) d) e) f) g)

comfort zone in winter comfort zone in summer cross ventilation thermal inertia and selective ventilation evaporative cooling humidification passive solar systems

Zone where the combination of “temperatures” and “humidities” offers a sensation of comfort. Diseño bioambiental y arquitectura solar Martin Evans, Silvia de Schiller. Facultad de Arquitectura, Diseño y Urbanismo, Universidad de Buenos Aires

Thermal comfort in summer. The challenge is to produce comfort without recourse to air-conditioning. Means of heat penetration: part of the solar radiation enters a dwelling through the windows directly into the building’s interior (direct contribution) and another part is absorbed by the walls and roofing or roof structures that then convey it to the rooms in the house (indirect contribution). There are different ways of controlling the penetration of “heat”: Controlling direct and indirect solar contribution to the exterior The first step towards obtaining thermal comfort in dwellings draws on common sense and consists of controlling exterior solar contribution.


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Comfort in winter. What are the issues? Decrease heating needs by ensuring biological comfort, taking advantage of the climate

What strategies? (e.g. capturing, storing, releasing…) Controlling incidence of sunlight, drawing it into the building in winter. The simplest form of heating is the most direct: a south-facing window may be an efficient way of capturing sunlight. Storing the energy that comes into the building (by means of the thermal inertia of the walls and floors, which can store this energy and return it to us) Avoiding the impact of the wind on the building and outdoor living spaces

Avoiding the cold wall effect

What is our perception near a cold wall? The temperature we actually feel is the mean of the air and the radiant temperature (mean radiant temperature). When the difference in temperature between the different walls is too large (hot walls/cold walls), we feel a sensation of discomfort.

The hierarchical system of spaces ensures the transition between inside and outside: in-between spaces, which are apparently no longer in vogue, play an important thermal role. This buffer space helps to prevent the energy loss caused every time the door opens and creates a space of thermal transition between indoor and outdoor temperatures, providing a comfortable adaptation.

Collector walls: they capture solar energy, store it in their mass and pass it on in the form of heat to the interior after several hours, thanks to their thermal inertia (Traité d’architecture et d’urbanisme bioclimatique). This is the case of the Trombe wall (whose performance is conditioned by climatic factors and the orientation and inclination of the wall) or air collectors (walls or window). Some ways of capturing solar energy are: Greenhouses and verandas are buffer spaces that help to capture solar radiation, which is transformed into heat by the greenhouse effect. Issues requiring further attention are:

The risk of overheating during the day in summer

The risk of night-time cooling in winter.

The inertia of the ground can be used to stabilise the indoor atmosphere, thereby obtaining comfort. The ground has thermal insulation capacities that are much used in vernacular architecture. The ground can even be used, thanks to its inertia, to preheat the air in winter (the temperature of the ground being higher than that of the air) and to cool it in summer (the ground temperature in summer being lower than that of the air). These systems allow us to obtain thermal comfort at the lowest cost to the environment.

The movement of air is directly related to comfort. This includes two possible speeds: the very low speed corresponding to natural convection, i.e. without ventilation, and the maximum admissible speed of a (hot) air current obtained by means of ventilation. The result is two curves that represent the outer limits of comfort with and without ventilation.

Low-emissivity triple glazing: 0.7 W/(m2K) Glazing: there are various factors involved in the choice of glazing. Is its purpose to collect or conserve energy, or to manage the hot or cold wall effect? How much natural light does the choice collect? The choice of glazing is complex and calls for particular reflection according to the needs of thermal, energy and lighting comfort, as well as of the activity accommodated by each space. For example, suitable thermal insulation helps to decrease loss and create comfort.

Rare gas: 1.1 W/(m2K)

Double glazing with reinforced thermal insulation: 1.8 W/(m2K)

Classic double glazing: 3,3 W/(m2K)

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Above we explained how solar thermal radiation basically comprises direct or indirect solar contribution in the form of radiation, which conditions our sensation of comfort far more than the intrinsic temperature of the air. Solar contribution essentially comprises the solar radiation that finds the surface of buildings. The radiation acts on the envelope of buildings, walls and roofs, and on other materials such as the floors or pavements that absorb the radiation and re-emit it. The energy (manifested in the form of heat) is stored in the walls, enters the building, travels through the floor structures and other associated construction elements. This radiation is the source of discomfort. There is direct solar contribution through openings and windows, and indirect solar contribution through exterior walls and the associated construction elements through which they penetrate. Direct solar contribution constitutes a large heat load against which solar protection is effective. Indirect solar contribution is principally due to the insufficient or poorly designed thermal inertia and/or insulation of the dwelling’s envelope (walls, roofs). Furthermore, the untimely entry of overheated air, not indispensable to good ventilation, is also an aggravating factor. The role of closing and protective elements as regards thermal comfort and energy saving. Closing and protecting elements ensure: Direct mechanical protection by means of an obstacle (intrusion, fire, bad weather, wind) Protection of the building (heat, cold, corrosion) A source of comfort (thermal, visual, acoustic) Filtering of natural light. They also serve to characterize and give architectural value to façades. As regards solar radiation, closing and protective elements act thanks to the application of two essential principles: Insulation (a heat or light screen to radiation) Reflection (partial return, reflected from their outer face, of radiation) Depending on the nature of the closing and protecting elements, it may or may not be possible to combine the presence of each of these two types on the same glazed opening. The different types of closing and protective elements can be grouped as follows: Closing elements: shutters, blinds Protection: essentially blinds, subdivided into exterior, interior and incorporated into the glazing

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Curtains and films applied to the glazing A comparison of the efficacy of solar protection in the summer shows, for example, that exterior protections are in general appreciably more efficient than on the interior; those integrated between layers of glazing are of intermediate effectiveness. A white Venetian blind on the interior, fully let down, will reduce the radiation through the glazing by 44%, whereas on the outside it will be 85% effective. Most exterior protections at an opening will allow just 5 to 15% of the energy reaching it to enter the premises (CEBTP “Caractérisation …”, p. 57). Another notion to remember is the influence of the colour: a white cloth interior blind, fully let down, will lessen the radiation transmitted by 60% as compared to a scant 20% for the same blind in a dark colour, in the same conditions (Victor Olgyay, Arquitectura y Clima). These protections may be adjustable and even motorized to adapt to the intensity of radiation. According to the materials and systems used, they may be more or less difficult to maintain. It is important to bear in mind that cleanliness will affect their performance. Some protective elements Blinds: blinds are most effective if they are opaque and placed on the exterior. In these circumstances, they can massively (3459%) reduce solar contribution, thereby helping to improve comfort by lowering solar radiation and the surface temperature of glazing. Special glazings: glazings whose characteristics give them specific properties. These characteristics depend principally on the thickness of the air cavity, the composition of the gas present between the two lights, and the nature of the frame elements. Sunshade and projecting roof: architectural elements that project to provide increased shade and absorb excess solar heat in the summer, allowing the sun to shine in during winter without concealing the field of vision from the window. Louvred blinds: exterior adaptable frames made up of openwork panels that can be folded back. Curtains: their efficiency can be considerably increased by backing them with reflective aluminium fabric, placed as near the glazing as possible. Shutters: adjustable panels to close openings. Roller blinds: horizontal elements such as rigid slats that roll up horizontally and block out the sun. Vegetation: preferably deciduous trees and vegetations that allow sun to shine in during the winter (seasonal shading). Deciduous trees protect the façade in the summer and allow energy gain in winter. Vegetation oxygenates and cools the air


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by evapotranspiration and filters suspended dust particles. Trees thereby reduce the effective exposure to the sun by 2040%. Vegetation can provide a screen against wind or guide it according to our needs. Sunshades and porch roofs are solar protections that can shield exposed walls and openings. Among other things, they provide protection from direct solar radiation.

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The internal contribution made by domestic equipment may be quite considerable and cause discomfort. Another internal contribution to be taken into consideration is the product of the calorific contribution of the occupants in the event of over-occupation. The importance of colours The colour of walls has a big influence on the temperature of their surface. The lighter and more reflective they are, the more they reject solar energy. Thermal protection of roofing. Whether the roof is horizontal or sloping, and comprises tiles, metal elements or other materials, it is the component that receives most insolation and contributes most to thermal exchange. Judicious thermal insulation is therefore vital for both comfort and energy saving. Insulation by means of a sufficiently thick layer is an important contribution to comfort in both summer and winter, not to mention the corresponding improvement in acoustic comfort. The role of inertia. The inertia of a building measures its capacity to store heat and slow its loss. It thereby helps to attenuate the effect of overheating due to solar contribution. Its contribution is, then, vital for façades that face the sun, depending on the climate and place, and is especially important in climates with large diurnal temperature differences. Massive walls and heavy roofs mitigate the effect of these large differences. Comfort and over-occupation. The heat produced by the metabolism is by no means secondary, and it accumulates. Further, the air pollution of rooms inhabited by many people obviously varies according to the number of individuals. Occupants give off heat and moisture. A seated person gives off in the region of 100 watts at an ambient temperature of 25°C. One way of limiting internal thermal contribution is to avoid overoccupation. Use natural lighting and limited, well-chosen artificial lighting: for reasons of economy and thermal and visual comfort, it is desirable to use natural lighting in the daytime, which does not mean letting solar radiation directly inside. In the evening and at night, when natural lighting is insufficient, it is a good idea to use lowconsumption light bulbs. Halogen lights increase room temperature considerably. Limit the use of exothermic household appliances. Electrical domestic appliances also give off heat. It is worth knowing the

Solar protection: reduces overheating due to solar radiation, and increases the insulating capacity of windows.

Vegetation oxygenates and cools the air by evapotranspiration. It also filters suspended dust particles. By means of evapotranspiration, vegetation contributes moisture to the air and the evaporation mechanism consumes energy, producing a drop in summer temperatures.

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consumption of each apparatus, which is listed in the manufacturers’ notices.

Natural cooling systems 3

Ventilation. Natural cooling by means of ventilation is feasible and worthwhile when it is cooler outside than it is inside. In general, at night the exterior air temperature is lower than inside dwellings (except during the hottest period), and ventilation should take place at the coolest hours of the night (between midnight and six a.m.). This night-time cooling effect can be increased by opening windows in opposite façades, where possible. In dwellings built on two levels, the effect is even more marked if the open windows are in opposite façades on two different levels (chimney effect). Evaporative cooling. The use of expanses of water creates microclimates and lessens diurnal temperature variations. Different aspersion systems also cool ambient air. Misting procedures may also be used. With high temperatures and low relative humidity, water evaporation will bring down the temperature by increasing humidity. The fountains in Arabic courtyards are one example. The thermal inertia of the ground: the earth heat exchanger. This system can only be used in buildings surrounded by sufficient land with available subsoil. It requires modest investment and a level of technical knowledge that places it within the reach of numerous professionals. Continuing performance and comfort are dependant on regular maintenance. Initially, the system consists in introducing exterior air to renew the air inside the house through a conduit

Surfaces of water help to create comfortable microclimates (Spain).

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that is naturally maintained at a lower temperature than that of the exterior atmosphere, as it is sunk deep in the subsoil. This system also serves to preheat the air in the winter, as its passage through the conduit raises the temperature of the air taken in. Performance is largely dependant on installation conditions: the nature of the earth, the diameter, nature and length of the conduit, the rate of air flow, topography and thermal insulation of the parts of the conduit above ground, etc.

1 Contact : Maria.Lopez-Diaz@anah.gouv.fr


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Acoustic comfort in existing homes

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Christian Thiriot Technical Directorate of the Agence Nationale de l’Habitat (ANAH), France

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Noise is way ahead at the top of the list of nuisances bemoaned by the French1, being all the more unbearable when it affects them in their own homes. We therefore have to consider the physical reality of noise and its effects, which depends largely on its source, type, time of emission, emergence and repetitiveness, etc. For example, a dripping tap can ruin a night’s sleep, though the noise represents just a few millionths of the sound energy of a vehicle in the distance that does not bother anyone. The air space between the two boards acts as a buffer2

The production of noise Noise is a vibratory phenomenon that is propagated in the surrounding air, either directly or indirectly. If the sound source is propagated directly in the air, for example by means of a loudspeaker, we speak of airborne noise; according to whether the source of this airborne noise is inside or outside the home, we refer to interior or exterior airborne noise. If the air is caused to vibrate by coming into contact with an element that receives an impact, such as a hammer blow against a wall, it is impact noise. If the air is caused to vibrate due to the functioning of equipment, such as a washing machine, it is equipment noise. It is further possible to distinguish between equipment noise outside the home (lifts) and the noises of indoor equipment. Noise may of course respond to several headings: a lift produces airborne noises by means of its motor, impact noises by means of its doors and equipment noise caused by the movement of its cabin. Depending on where one happens to be, one of these noises could appear to be predominant.

The perception of noise The subjective part in the perception of noise is frequently more important than the noise level as measured by a sound-level metre; for example, the noise of a water heater switching on may reassure an owner-occupier, whereas it could irritate a tenant. Likewise, tiredness or stress, or the kind of relation one has with one’s neighbour also affects one’s perception of the noises he makes.

The transmission of noise Whatever the type of noise (airborne, impact, equipment), it travels between its source and the point of reception along complex, often multiple paths, preferring those that present the least resistance, which are called sound bridges. Thus an exterior airborne noise will pass easily through an open window, and an impact noise or an equipment noise will be easily transmitted by a partition or piping. The limitation of the discomfort due to noise involves first limiting it at source and second introducing appropriate obstacles between the source and the reception point, bearing in mind that the paths taken may be multiple and difficult to locate—there is no point closing one window if another is left open. Furthermore, it is important not to underestimate the masking effect of continuous noise such as the outdoor traffic. In this case, the installation of soundproof windows may lead to the appearance of interior noise, such as equipment noise that was hitherto masked but is now more noticeable! The phenomenon of reverberation also has to be taken into account: it generally affects sufficiently large rooms with walls that are rigid or tiled, for example. Normal furnishing will attenuate this phenomenon but it may be necessary to implement complementary measures in the form of acoustic treatment. Reverberation often affects communal areas such as corridors and foyers, producing an uncomfortable noise environment.

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I. Airborne noise

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Apart from the preferred process of reducing the nuisance at source, which is not always practicable, the main obstacle to exterior and interior airborne sounds are horizontal and vertical facings, walls and partitions. These walls are all the more effective against airborne noises as they are not generally susceptible to vibration, and heavy walls in particular are highly efficient in acoustic terms. Of course, a heavy wall with windows in a poor state of repair is less of an obstacle to airborne noise, since it is the weakest part, the window, that governs the overall effectiveness. There are, however, also light walls, partitions comprising two gypsum plasterboards joined together by a metal frame, that also have excellent soundproofing qualities; the air trapped between the two elements then acts as a buffer and attenuates airborne noise. Their level of efficiency can be further improved by filling the space between the plasterboard with special fibrous materials, generally mineral wool. It is also possible to increase the number of gypsum wallboards, this being a particularly appropriate solution for the rehabilitation of old dwellings, as the resulting partition is lightweight and represents a minor added load on the building’s structure, at the same time offering comparable efficiency to heavy walls. These solutions, however, can only be employed for interior partitions.

The use of absorbent material attenuates noise transmission

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a. Exterior airborne noise To counter exterior airborne noise, rehabilitation work has to focus principally on the weak points, specifically doors and windows, air inlets, rolling shutters and roof structures. It is necessary to ensure that these interventions do not compromise ventilation systems; the interior comfort of the dwelling could otherwise be affected and the built fabric will suffer. Doors and windows The principal aim is to suppress any direct entrance of air and, with it, all means of transmission of exterior noise. A careful examination of the situation by a professional, known as an acoustic diagnosis, should produce the best solution for the budget available. Conservation of the opening leaves, fitted with acoustic glazing. In this case, it is important to ensure that the fixed frame and the opening leaves can bear the additional weight of the glazing, which is considerable. Replacement of existing doors and windows by new airtight elements fitted with acoustic glazing. If the fixed frame is in a good state of repair, it may be conserved. Construction of a double window. When correctly carried out,

Construction of a double window.

The passage of air transmits exterior noise


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this solution is highly effective and also conserves the exterior appearance of the façade, an important factor when dealing with valuable heritage. NOTE: Double-glazing for insulation generally makes little difference to soundproofing, especially if the two lights are the same thickness and quite close together. It is advisable to choose specific windows (with opening leaves and fixed frames) and glazing whose acoustic properties are specified on the product. It is also advisable to ensure that the ventilation systems generally associated with windows do not counteract their acoustic performance. Air intakes There are specific air intakes, referred to as acoustic, with facings that are lined with absorbent materials. These cut out exterior noise and allow correct airing of the dwelling. If the replacement doors and windows are not fitted with built-in air intakes, it is advisable to restore ventilation, possibly by effecting openings in the masonry. Rolling shutter boxes These boxes often constitute an acoustic weak point in the façade. The situation can be improved by replacing the existing boxes by

Acoustic weak points.

denser materials and blocking up all direct entry of exterior air. If possible, the inside of the box can also be lined with insulation materials such as mineral wool or absorbent foam (see above). If replacement is chosen, the element should be substituted by window blocks with built-in rolling shutters, which are good acoustic performers. Roofs Roofs are particularly sensitive to exterior noise, especially aircraft noise, which is particularly annoying after building a loft conversion. An initial solution is to have thermal-acoustic insulation fitted. If this proves to be insufficient, it will then be necessary to have recourse to more extreme solutions, such as separating the roof from the rest of the building’s structure. b. Interior airborne noise Interior airborne noise calls for interventions to structural floors, separation walls or landing doors and partitions. Structural floors (and ceilings) Structural floors (and ceilings) may be acoustic weak points as a result of the pipes that run through them. This may be due to gaps that let sound through, in which case elastic sleeves or soundproofing materials should be fitted, or to excessively rigid

Common walls in dwellings.

A light wall does little to reduce the noise perceived behind

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connections of pipes to structural floors, in which case the elements should be separated, for example using vibration cushioning to prevent the vibrations of the pipes being transmitted to the structural floor or ceiling. The direct passage of noise through the facing is counteracted by packing the gaps with soundproofing material. If the noise is transmitted directly by the structural floor of the dwelling upstairs it may be necessary to consider the construction of a double ceiling according to the same principle used in the case of common walls. It is vital to carry out a diagnosis of secondary transmission, particularly by vertical partitions, since this may be the primary cause, making the construction of a double ceiling both expensive and ineffective. Furthermore, the routes taken by sound in old buildings can be complex and require professional analysis. Common walls Thermal insulation materials placed on the interior of dwelling walls are often so rigid that they reduce the acoustic performance of the facings between homes. It is advisable to replace them with suppler thermo-acoustic materials, which are attached by bonding or inserted between the wall and a gypsum wallboard attached to

An incorrectly built floating floor is ineffective and may even aggravate sound transmission

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a metal frame. The same solution can be applied if the transmission of noise between dwellings is caused by structural weakness of the common wall. Landing doors and partitions Landing doors with acoustic weaknesses should be replaced by officially approved doors. Partition walls between a dwelling and a landing can be addressed in the same way as partitions separating dwellings (see above).

II. Impact noise and equipment noise The lighter a wall is, the more transmission of noise will be facilitated by direct contact between the facings of a dwelling and the parts subject to impact or vibration. Various resources are available to resolve this problem, including anti-vibration supports, cladding laid over underlay, floating floors, suspended ceilings, etc. It is important to remember that pipes can carry impact noises a long way. Likewise, the slightest error in the fitting of soundproofing

Structural transmission of the noise.


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mechanisms can ruin the entire noise attenuation system. In particular, any point of direct contact of a floating floor with its support will render this major investment ineffective. Impact noise The structural floor The principle of intervention consists in preventing the element from vibrating when subjected to stress due to the impact of an object. One solution is to cover the floor of the dwelling where the noise is created by a form of cladding that will absorb impact (carpet, plastic flooring with resilient underlay, etc.) or to introduce a resilient layer between the support of the structural floor and the floor cladding that is sensitive to impact noise, such as a tiled floor or rigid parquet. Another, fairly extreme solution would be to build a floating floor, which should be entrusted to an experienced professional to ensure its proper construction. Intervention on the structure If it is not possible to intervene in the dwelling where the noise is produced, it will be necessary to introduce barriers to prevent their transmission. This requires a diagnosis carried out by specialists, requiring the intervention of an acoustician.

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water pressure is not excessive. Likewise, an extractor outlet will hiss if the airflow is not balanced. Passive equipment such as pipes must in all cases be attached to heavy walls by non-vibrating clips. Intrinsically noisy equipment such as an extract ventilation motor can be effectively suspended and enclosed in casing lined with absorbent materials. Reverberation Acoustic correction consists in general of cladding walls with absorbent coverings; in this case, the characteristics of the facing with regard to airborne noise are not modified.

1 See the technical leaflets published by the ANAH, particularly “Bruit et confort acoustique and Bruit”. 2 The idea of the illustrations are provided by the CSTB on behalf of the ANAH.

Equipment noise Intervention on equipment In France, most electrical domestic appliances, boilers and plumbing fixtures have an NF mark that specifies their acoustic performance; nevertheless, their application will be dependent on external factors that have to be taken into account and corrected as applicable. A quality tap will only be silent if the

Noise perceived behind a heavy wall is considerably reduced

The use of absorbent material improves the sound comfort of the room but does not decrease the transmission of the noise to the room next door

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Preliminary reflections on the graphic survey of vernacular heritage

Santiago Canosa Reboredo, Architect Lecturer in the Department of Architectural Representation and Visual Analysis II and Director of the Architecture Heritage Workshop, School of Building Construction of Barcelona (Technical University of Catalonia), Spain

It is difficult to argue the issue without referring to the Charter on the Built Vernacular Heritage, ratified in Mexico in October 1999, and above all to its familiar introduction, which clearly defines the concept of vernacular heritage and warns us of its fragility. This is why, when asked to write this article, I could not pass up the opportunity to make my own contribution to the huge effort that must be made if its continuity and protection are to be guaranteed. I should also point out, evident as it may seem, that although rural heritage has its own characteristics, the methodology and techniques used in its graphic survey differ very little from those used to survey the other buildings that make up built heritage. Perhaps the biggest difference lies in its irregularity, requiring greater precision in data collection. Having said that, I thought it interesting to base this section on graphic surveying, listing the various phases in the order I believe they should be carried out. A detailed description of this process will serve to establish principles that will guarantee successful results of the graphic survey. I would also like to establish some preliminary conditions. Our work forms part of a complete architectural survey, involving various specialists. The correct coordination of them is vital to the results. The graphic survey has been requested by a third party, who could be the director of a master plan, with a view to future intervention in the building being surveyed. In other words, the work we carry out is not for us. (Before beginning work on a building, it is necessary to consult any graphic surveys that have already been carried out, as they contain valuable information that serves both as a starting point and to compare and contrast results. Experience

has shown that many surveys, sometimes conducted by great architects, are very poor in content, serving as mere reminders of parts of the building.) Finally, I grant myself the utopia of not having a time limit to carry out the graphic survey, a premiss that is very rarely found. I will now go on to analyse the stages in the working process.

Defining the task It is very important to maintain close contact with the institution or person who requests the graphic survey with a view to clearly defining their purpose and discovering the use to which the data we supply is to be put. The survey will be approached differently according to its purpose: restoration, rehabilitation, consolidation, collapse, documentation, etc. Since the content of the work is basically the same, we have to complement it in different ways, using different systems of representation, varying scales or studying different types of detail. The directionality of the survey is important. Who is the work for, and in what form do they wish to receive it? Should the presentation be varied depending on whether it is for an architect, an archaeologist or an engineer?

Reconnaissance I start out from the premiss that the time and money I invest during the preliminary information-gathering process will always be profitable and save work later on. I therefore suggest:

An alignment system situates the detail of the various rooms in a distribution and therefore correctly defines the thickness of the enclosing walls.

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Tool 4 Making the graphic survey of the building Preliminary reflections on the graphic survey of vernacular heritage

4 A closed station system will correctly produce the environment of the building to be mapped.

Consulting bibliographical sources, the archives of municipal, civil and religious institutions in the area of the building, checking iconography, and contacting people who are now related with the building or have been in the past. Experience shows that vernacular architecture, perhaps because it is created by its users, creates important bonds. These bonds last for generations, and the users tend to keep the few documents generated by the different stages of construction, as well as maintaining an equally important oral tradition. The Catalan masia or farmhouse is proof of this; a high percentage of masies continue to be inhabited by the same families that built them. Keeping in contact throughout this phase with the other professionals involved in the architectural survey. Together, the various professional will situate the building in its historical context, which will help them to identify the needs and concerns of the users, their socio-cultural background and the stages of construction, and correctly interpret the building’s specific elements. The applied arts will help us to correctly date each intervention and other similar appreciations will help us towards a fuller understanding of the building. Direct reconnaissance of the building: finding our bearings, situating ourselves, recognising the phases of its construction on site, familiarising ourselves with the layout and which rooms have direct access from the room in which we are standing. This is when you should take your first notes and start a large collection of photographs. It is advisable to spread this process over several days, particularly if the building to be studied is a complex one, and periods of reflection between visits will always bear fruit. I have always thought that the process of conducting a graphic survey is the opposite of the process carried out by the architect or master builder when building it: he devised a way of creating spaces that would meet certain needs, and, on the basis of some initial sketches, gave form to his work on paper and then built it. We, on the other hand, start with the built work, draw sketches

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By applying simple topography programmes to a collection of points taken beneath a vault, we can define its horizontal sections and therefore, its regularity.

Data collection using a non-prism total station will help us to situate the basic lines of our building in space.


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to produce plans of the initial project, and, if we continue, we may come to intuit the original idea that led the master builder to define the spaces and volumes and their interrelation, the original idea that generated the project, or the phase of the project we are analysing. If so, we will certainly realize the greatness of the mind that conceived it. Unfortunately, this does not always happen, but if we reach this degree of knowledge, it is the ideal place to start conducting our survey. During the reconnaissance process we will decide what projections are needed to satisfactorily define the geometry of the building, the systems of representation and appropriate scales to use, and the order in which to carry them out. I particularly stress the concept of order, because many mistakes can be avoided— and, with them, the journeys to correct them—if we are sure of having the correct information that could have been provided by a projection that we have deferred.

Field and desk work Each projection you decide to carry out requires a twofold process: data collection in the field and subsequent application at scale. I have to stress the fact that new technologies applied to these processes make them increasingly interdependent. As of the first sketch, it is necessary to start thinking about the right way to obtain a correct interpretation. To give just two examples, the attempt to represent at scale the multiple projections generated by a groin vault, starting out with the traditional dihedral system sketch, will be considerably more complicated than reconstructing the same vault in three dimensions, using a good computer-aided

Photographic back-up is vital when taking points using a non-prism total station. The camera should be placed in the same position where the station will subsequently be set up. If the points are surveyed vertically, as in series 3-6 and 8286, we can determine the verticality of the edges during the data collection process. An arch can never be defined solely by surveying three points.

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drawing program, and sectioning and projecting it onto as many plans as necessary. Further, it is obvious that data collection for the two processes will be different. The photograph is the ideal support for data collection when using a non-prism total station, particularly these days, with the immediacy of digital photography. In its absence, we would have to produce multiple free-hand perspectives that would allow us to identify points in space. I do not, however, mean that we should give up “classic” data collection using dihedral or axonometric systems, which is still vital and in most cases would complement the data obtained using other systems. It is important to use the appropriate method of measurement (itinerary, base alignment, polygonal, radiation, etc.) for each type of construction or combine several of them, in this case with particular emphasis on the way in which the various methods are related. Evidently, the ideal method is the one that guarantees the least accumulation of errors. In the interiors of buildings with few divisions, it is generally advisable to use a network of stations to provide data about both the floor plan and sections and elevations. Conversely, when the interior distribution is important, the base alignment system tends to work best. However, I do not aim to dictate a working system; each case has to be weighed up individually, and the construction itself question will govern the appropriate work system. The irregularity of vernacular architectures is real, not merely apparent. Though the aim may have been to obtain parallel lines and symmetry, the lack of perpendicularity in the various rooms is characteristic and the varying thicknesses of the walls, both in the floor plan and in section, is considerable, and verticality is relative. This all depends on the construction phase, the system of support used for the ceilings on the different floors and the skill of the workers, normally the occupants of the house, in most cases directed by an expert. All of these factors require horizontal working plans in order to guarantee the correctness of our work, relating the different floors by means of non-bearing elements (stairwells, courtyards, façades) and never on the basis of supposed verticals that rarely exist. It is often necessary to use different systems to measure the interior and exterior of a building, or its different floors. In these cases, particular attention should be paid to the correct relation of the two systems. Each method must be based on its own system of dimensioning (partial, point of origin, polar, etc.), thereby guaranteeing the least accumulation of error. An issue that has always caused some uneasiness on my part is the dichotomy between the precision of the latest measuring apparatus and the irregularity of the buildings that make up our vernacular architecture and built heritage. Just how precise do we have to be? Do we have the right to simplify the data obtained? Should this produce two different surveys? I leave the question open to the floor.

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Above, I mention the interrelation between field and desk work. It is important for the two to coincide in time, as this will assist us in the task. It is not a good idea to let field data build up, unless it is unavoidable, putting off later desk work. It is easy to forget details that may be determinant in the process. Writing up the day’s material makes us reflect on the efficiency of the data collection process and introduce possible improvements. The support represented by completed projections for the collection of new data is important, as it allows us to check our figures on site. It is important to remember, as I mentioned early, that our graphic survey is just one part, though important, of the architectural survey that will be used by the other professionals involved, as material to support their interventions. Archaeologists, geologists, art historians, property cataloguers, etc., will need a graphic survey to contextualize their contributions. Before the start of work, a series of agreements should be made as regards unity of language in order to facilitate greater ease of comprehension of the overall architecture survey. By way of conclusion, I would like to say that this article is to a large extent the product of study and the reflections generated by many mistakes made in the course of what is now a good number of years devoted to architectural survey, but most of all to the shared experience with my colleagues and research students in the Taller de Patrimoni Arquitectònic2 (TPA, Architecture Heritage Workshop) at the Polytechnic University of Catalonia.

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“The built vernacular heritage occupies a central place in the affection and pride of all peoples. It has been accepted as a characteristic and attractive product of society. It appears informal, but nevertheless orderly. It is utilitarian and at the same time possesses interest and beauty. It is a focus of contemporary life and at the same time a record of the history of society. Although it is the work of man it is also the creation of time. It would be unworthy of the heritage of man if care were not taken to conserve these traditional harmonies which constitute the core of man's own existence. The built vernacular heritage is important; it is the fundamental expression of the culture of a community, of its relationship with its territory and, at the same time, the expression of the world's cultural diversity. Vernacular building is the traditional and natural way by which communities house themselves. It is a continuing process including necessary changes and continuous adaptation as a response to social and environmental constraints. The survival of this tradition is threatened worldwide by the forces of economic, cultural and architectural homogenisation. How these forces can be met is a fundamental problem that must be addressed by communities and also by governments, planners, architects, conservationists and by a multidisciplinary group of specialists. Due to the homogenization of culture and of global socio-economic transformation, vernacular structures all around the world are extremely vulnerable, facing serious problems of obsolescence, internal equilibrium and integration. It is necessary, therefore, in addition to the Venice Charter, to establish principles for the care and protection of our built vernacular heritage.”

2 My principal experience of recovering rural heritage is the work we carry out in

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the TPA on the Catalan masia, based mainly in the areas around Collsacabra and the Montseny, two regions that are very close, separated only by the river Ter basin, with very similar orography but quite distinct evolution of their masies and in both cases, unfortunately, with discouraging results. The masies in Collsacabra tend to be large, the casa pairal or family seat, some the product of endless extensions, others reminiscent of the region’s old noble families. The orography of the area meant that they mainly concerned themselves with stock-keeping, with small tracts of land devoted to agriculture.


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Pointers for drawing up a good survey

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Michel Daoud Architect Lebanon

Introduction An important preliminary to any restoration or consolidation work is the drawing up of a current condition of premises report. The purpose of this report is to provide the necessary support and database for subsequent historical and technical studies involved in an architectural analysis of the building. It may be represented graphically, photographically and/or descriptively. In historical architecture, the concept of mapping is no longer limited to simply taking exact measurements of what exists. It now includes important scientific and historical aspects when recording the specific characteristics belonging to each architectural typology.

Graphic mapping This involves representing an architectural construction on a support such as paper in order to:

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Current state (faรงade of Baroud House, Tyr)

Facilitate its interpretation and understand its dimensions and proportions Establish its coordinates, position in space and relation with its surroundings Detect structural anomalies: fissuring, differential settlement, sliding, etc. Identity the construction materials and decorative elements Produce precise documentation of the current state of the building

Graphic survey (floor plan of Baroud House, Tyr)

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Surveying methods There are generally considered to be three methods of graphic mapping: manual, instrumental or topographic, and photogrammetric.

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Manual mapping consists in taking direct measurements using the classic measuring instruments: surveyor’s chain, spirit level, marker posts, plumb line, compass, etc. Topographical mapping consists in using optical measuring instruments: theodolite, tachometer, goniometer, etc. Photogrammetric mapping consists in using photography and computer programs to conduct the survey. The graphic survey involves two essential phases: one is manual (site sketch and notes) and the other is the line drawing. The first consists of producing a drawing of all the floor plans, sections and elevations of the construction onto which all the dimensions and measurements will be transferred using a suitable

Interpreting the built work (façade of Baroud House, Tyr)

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scale to facilitate comprehension of the drawing, as well as descriptive indications, and the comments and remarks made on site, known as the site notes. To conduct this surveying phase you need a brief case equipped with drawing paper, pencil, rubber, etc. The document produced by this phase must be carefully conserved for consultation during future graphic reproduction or to respond to new requirements. The second phase is the production of a scale line drawing. North, the scale, the location, the date of the survey, and the name of the author must be indicated on the drawing board. This phase may be carried out directly on a paper support or using information technology. The topographic survey is considered a complement to verify the manual survey. In some cases, it is vital in order to survey points that are inaccessible. It is above all a precision survey in the case of integration of the construction into the urban network.


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Photogrammetric survey In the event of inaccessible points or when measuring equipment is not available, photogrammetry is a quick and simple way of surveying a building. It simply involves taking two photos of a single object using a special photographic apparatus and developing them using special software to establish the perspective and reproduce the “photo-elevation” in two dimensions Photographic documentation As a supplement to the graphic survey, photographic documentation illustrates the condition of premises report at the time of the survey. It is vital for knowing the volume of the building plus details, colours and the materials used. Much information about the state of a building can be recorded on paper using photography, whereas the plans and elevations of the graphic survey are merely geometric and scientific drawings that conceal a great deal of knowledge.

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Stratigraphy The survey allows us to determine the stratigraphy of a construction. In fact, it should facilitate the interpretation and understanding of the different phases of construction and the transformations a building has undergone, allowing us to understand the work and perceive all of its historical and technical values. When interpreting the building, the person carrying out the survey will be able to identify the phases of construction by interpreting the list of dimensions, volumes and materials used, and by means of the different construction techniques. Typological studies A comprehensive survey should compare the building’s different typologies. The proportions and dimensions of architectural elements, and the forms and spaces allow us to identify the typology and dating of each part of the building.

Colour study (interior renderings of Mamelouk House, Tyr)

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As well as being a simple measuring operation, the graphic survey of the condition of premises report also constitutes a database that can be used to determine the historical and cultural values of the monument. Colour studies

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The survey includes a colour catalogue: the stone, renderings, timber and paint used in the building. This survey must identify the different colours of the various layers of paint or whitewash and their type: oil- or lime based, etc. Files comprising the location, drawing and colour will serve as documentation for comparative studies of colours or for future analysis or research. Architectural analysis of the building The scientific survey of a work of architecture represents a whole series of lines of investigation: knowledge of techniques used,

Analysis of modules (faรงade of Baroud House, Tyr)

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materials, construction and structural systems, etc. Architectural analysis may also provide information about the function and the activities that took place in the building. This analysis enables us to identify and understand the specific characteristics of the work of architecture: a report on the dimensions, modules, architectural typology and spatial values. We can as a result tell the original parts from later transformations. Conclusion Above I highlighted the importance of the survey to the current condition of premises report, which is an absolutely vital preliminary to restoration work or historical research. A detailed survey must be completed by a written description and a photographic and petrographic catalogue in order to present all aspects of construction. Information gaps in the survey may hinder the historical or archaeological hypotheses proposed for interpretation.


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Graphic Survey. The Cypriot experience

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Eleni Pissaridou, PhD in architecture Department of Antiquities, Cyprus

The rehabilitation of a traditional building presents several challenges to the architect/engineer assigned to the project. Through the project, the architect/engineer is called to understand the many aspects of the building, its traditional architecture and, while preserving and respecting the architectural heritage, enable its transition to future generations in a time-sustaining condition.

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One of the critical elements of the study is to enable the restoration of the traditional building with minimum intervention to its architecture, building methodology and materials, while making it a comfortable dwelling, addressing the needs of modern-day inhabitants. After the assignment of the rehabilitation of building to the architect/engineer, s/he will need to pay a visit to the site, during which, s/he will make the initial assessment of size, spaces and condition. There are examples where the building is unstable and needs immediate basic support or needs site cleaning and careful removal of debris so that the architect/engineer can work in and around the building for the graphic survey. Site cleaning should be done very carefully, while looking for evidence of building components and material that can be used for its restoration. There are several methodologies or practices of graphic surveys, such as the photogrammetric survey, the digital scanner survey and the traditional graphic survey. The latter is largely manual in nature, using tools such as tape measure, level, plumb line, altometer, etc. Whatever method is chosen, the end result should be a series of accurate plans (plan views, side views, sections and architectural and construction details). The traditional graphic survey methodology starts with the initial sketches, which must be clear and proportional.

Measuring dimensions requires accuracy and at least two persons

Detailed plans are generated in order to depict unique elements, e.g. a door detail, a window, a decorated ceiling, wooden construction. The graphic survey is complemented with notes on the plans, explaining details not depicted in the plans (e.g. layers of plaster or colors) or memory sustaining elements, as well as good photographic documentation. The final result, a complete, accurate and detailed survey helps not only the overall study and analysis of the building, but will also help in the formulation of the right proposal to address the problematic areas, such as restoration of damages, re-plastering and repositioning of architectural elements. Lastly, the graphic survey helps in making correct changes or additions, within the spirit of preserving the architectural heritage, as well as meeting contemporary functional needs.

This is followed by measurements for which at least two persons are required (horizontal, vertical and diagonal). During the graphic survey, the architect studies and generates deep understanding of the building, its architectural structure, details and characteristics, materials, construction techniques, prior interventions, and possible problems (lesions, variations, humidity, etc.).

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Initial Sketch with accurate dimensions

Initial Sketch and details with useful notes

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Plan view of ground floor

Faรงade of the building

Plan view of first floor

South Elevation

Sections

North Elevation

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Stratigraphic analysis of architecture and its application to traditional architecture

Tool 4 Making the graphic survey of the building

Camilla Mileto, Doctor of Architecture Lecturer in the Department of History and Theory of Architecture, School of Architecture of Valencia (Technical University of Valencia), Spain

Stratigraphic analysis of architecture 4

Stratigraphic analysis applied to architecture, tracing the material marks engraved in the masonry, allows us to document and study the different construction periods in the history of the building. The construction process, with its different actions of construction, demolition and transformation, leaves a series of traces recognisable to an eye that is trained to identify and understand them. While a stratigraphic study of architecture allows us to identity the different construction phases, it also favours the knowledge and recognition of the construction materials and techniques used in the architecture. Stratigraphic analysis came into being as a way of excavating and studying the archaeological site and it has been applied to the study of historical architecture for the last 20 years or so. Its use in the world of archaeology is based on the concept of stratification, which came into being in the field of geology as the superposition of strata in a natural terrain (geological stratification). The largescale research such as that of Harris (1979) and Carandini (1981) defined and codified the stratigraphic study of archaeological stratification, understood as the superposition of anthropogenic strata on an archaeological site. In the late 1980s, architects who were working on architectural restoration (particularly Doglioni and Parenti) and archaeologists concerned with architecture (Brogiolo, Francovich, etc.) realized the potential of this type of study for the documentation and interpretation of historical architecture undergoing restoration. In most cases, historical architecture is characterized by its complexity due to the number of different interventions it has undergone in its lifetime. The mutability of historical architecture allows us to establish a parallel between archaeological and architectural stratification, in which each stratum can be identified with a different action of construction, demolition and transformation.

Method and application The application of stratigraphic analysis to architecture has recourse to a series of fundamental concepts of stratigraphic archaeology, adapting them to the study of architectural constructions. However, the complexity of architecture and its peculiarity call for particular attention to construction techniques and processes as basic elements in understanding and interpreting

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Architectural stratification: series of strata and interfaces

architecture from the point of view of its evolution and modification. Architectural stratification represents the construction phases and periods of use of a building throughout its history. The construction phases are characterized by positive actions of construction, negative actions of demolition and transforming actions that modify what exists. The periods of use interposed between the successive construction phases are characterized by anthropic wear as a result of use of the building and natural deterioration caused by atmospheric agents. Architectural stratification is manifested in a series of strata—that is, the remains of the different actions that have taken place in the course of the building’s history and negative interfaces, which are the prints of demolitions. In the case of architecture, the stratum may be a foundation, a wall, a floor slab, a roof, a rendering, etc. Every time part of a building is constructed, it represents a stratum with its defining characteristics: a body of stratum (its mass) and the surfaces that delimit it. In the case of architecture, the surfaces often constitute the only visible part of the stratum (the two faces of a wall, the surface of a rendering, etc.), which is therefore the only part that can be documented and studied. Further, the surfaces often conserve important data about the decoration or finish of the architecture, or its use.


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The first important difference between archaeological and architectural stratification is the order of deposition of the strata: in the case of an archaeological site, the strata are deposited according to the laws of gravity, starting with the oldest, so that the upper stratum is more recent than the most underlying. In the case of architectural stratification, conversely, the strata are layered in all directions, creating greater difficulty of interpretation of the order of deposition. There is a second basic difference between application of the method in the fields of archaeology and architecture. Archaeological investigation involves the progressive elimination (excavation) of the strata present on the site, since each stratum is superposed horizontally on the older one below, concealing it completely. In the case of architecture, the stratigraphic method investigates the strata deposited from ground level upwards—that is, the building that is still standing. In this case, elimination of the strata is generally not envisaged, since each stratum is part of the existing building and constitutes part of it (its structures, finishes, spaces, etc.). The stratigraphic unit is the general term covering the strata and the negative interfaces. In the case of architecture, the stratigraphic construction unit can be defined as a homogeneous area, carried out according to a single constructional decision to build, demolish or transform. The stratigraphic units can be distinguished by construction materials and techniques, colour, composition, finish, surface cutting or carving, etc. The stratigraphic unit is delimited by a perimeter that separates it from the next units. It is in this perimeter that we can identify the relations existing between the various adjacent stratigraphic units. Stratigraphic relations can be recognised in the type of relation between two units that meet. Stratigraphic relations can be contemporary (two units constructed or carried out as part of the same construction process) or before/after (two units constructed or carried out in two different successive construction phases). Contemporary relations comprise bonding, in the case of two units built together (for example two connecting walls) and same as in the case of two units that were built at the same time but are not in physical contact (for example, a series of windows, all the same, inserted at the same time in a pre-existing wall). The before/after relations comprise built against, where the unit that is placed comes after the unit it is placed against (for example, a wall built against another comes after the first); covering/covered by, where the unit that covers comes after the one that is covered (for example, plastering on a wall comes after the wall); cutting/cut by, where the unit that is cut comes before the unit or interface that cuts it (for example, the action of demolition comes after the wall that is demolished); filling in/filled in by, where the unit that fills in comes after the unit that is filled in (for example, the bricking up of a window comes after the actual window).

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Stratigraphic units in the bridge at La Pobleta de San Miguel (Villafranca del Cid, Castellón). Each stratigraphic unit can be distinguished by the construction technique used

The stratigraphic relation of bonding (the dry stone wall is bonded to the top part, built at the same time)

The stratigraphic relation of placed against (the wall on the right is placed against the wall on the left)

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Once the stratigraphic relations between the different units are identified, it is possible to establish the stratigraphic sequence in which the units are ordered from the oldest to the most recent. The tool used to order the stratigraphic sequence is the Harris matrix, invented by North American archaeologist Edward C. Harris, which methodically orders all the units. In the case of a stratigraphic study of architecture, this can easily reach several thousand. The stratigraphic study always provides a relative chronology in which the units are ordered in a relationship of before and after. In this way, the stratigraphic study of architecture provides a sequence of units ordered from the oldest to the most recent. This sequence of units can be periodized—divided into the different periods that correspond, in the case of architecture, to the different construction periods in the building’s history. This periodization is based on the possibility of logically ordering the different interventions in a sequence: for example, for obvious reasons the construction of a floor slab and its subsequent demolition belong to two different, successive construction periods and, therefore, the stratigraphic units related to these interventions can be placed in the corresponding periods. The stratigraphic sequence does not provide an absolute chronology—that is, a chronology based on specific historical events. To be able to associate a specific date with the construction periods identified by periodizing the sequence calls for information gathered from other sources or other methods of investigation: documentary historical studies, chronotypology, mensiochronology, archaeometric dating techniques, etc.

The stratigraphic relation of covering/covered by (the plastering covers the wall)

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The stratigraphic relation cutting/cut by (the wall is cut into in order to insert the pipe)

The stratigraphic relation filling in/filled in by (the arch is filled in with bricks)


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Tool 4 Making the graphic survey of the building Stratigraphic analysis of architecture and its application to traditional architecture

Stratigraphic study of architecture and construction techniques The success of a stratigraphic study of architecture is closely linked to knowledge of the construction materials and techniques. The construction process involves the formation of a series of marks caused by the different actions carried out, and it is necessary to have in-depth knowledge of the forms of construction, or stratification, to be able to correctly identify the different construction phases. The construction materials and techniques are related specifically according to the construction process and the working tools used, which leave marks that can be interpreted on the basis of prior knowledge. Architectural masonries have different potentials for forming stratigraphic traces according to the type of material used. Mortar, plaster, rammed earth, masonry of brick, rubblework or ashlars, tiled floors, and all construction techniques that use wet materials (materials that acquire their strength when they set), create a compact continuous stratum. When this stratum breaks, it generates a scar that is difficult to conceal, as in the case of a seal. Furthermore, wet materials are placed against pre-existing elements, adapting to their form like a traced copy, so it is always possible to distinguish between the pre-existing element and the

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later, superposed tracing. Thanks to these two properties, in most cases it is possible to distinguish the part of the wall that was built first (the mortar in the wall constructed afterwards adapts to the shape of the pre-existing wall), demolitions and reconstructions and the insertion of later elements can be identified, etc. More complex is the interpretation of the construction phases using dry materials (timber, reeds, straw, dry stone, etc.) that do not require the use of mortar and are based on juxtaposition or the interconnection of parts. In these cases, the absence of mortar as a sealant (adapting to the pre-existing element) means that the parts can be moved or replaced without leaving a clear trace of any such movement. We often find houses in which a timber element, such as a joist or the roof sheathing, has been replaced without leaving a trace on the adjoining elements that have been easily dismounted and put back in the same position. Identification of the replacement then calls for other forms of observation, such as not just stratigraphic but also chronotypological methods, associated with the type of material, surface treatment, cutting or carving of the element, its form, etc. In most cases, the stratigraphic relations of dry materials can be established thanks to the point of contact with a wet material: the insertion or demolition of a floor or roof can in most cases be seen in the point of contact with the masonry (formation of the weephole at the same time as or after the wall), the insertion or transformation of a door or window frame can also be detected by observing the masonry in which it is set, etc. Mortar and other wet materials therefore play a vital role in the correct interpretation of architectural stratification. The elimination, replacement or manipulation of mortar in its different forms (bonds, plaster, whitewash, regulating courses, rammed earth, etc.) at least partially distorts the possibility of correctly interpreting architectural stratification. For example, complete pointing of masonry represents the elimination of the stratigraphic relations between the bricks or stones that make it up, whereas masonry can be conserved by means of selective pointing carried out only where necessary, without eliminating the existing bond. This observation suggests reflection on the relation between the stratigraphic study of architecture and the architectural restoration project. Stratigraphic study and restoration project

Construction of the stratigraphic diagram or Matrix Harris (drawing taken from E. C. Harris, 1991)

Firstly, a stratigraphic study is of obvious interest in relation to the information it can bring to bear on the building in question. A careful stratigraphic study of a building can reveal a great deal of data about its material history which is generally far broader, more detailed and accurate than its documentary history. In-depth knowledge of the material history of the building can also establish important relations with other areas of the preliminary study, such as the study of material and structural pathologies, the

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study of fissures and load analysis. In many cases, the structural pathologies or problems are determined by the very history of the building, the use to which it has been put or changing loads throughout the life of the structure. Architectural stratigraphy therefore provides a series of data that can be used in the overall study of the building.

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Architectural stratigraphy also plays an important role in the development of the restoration project. Stratigraphy shows the forms of stratification of the materials and presents the traces left on them by historical interventions. The restoration project, seeking to conserve the materiality of the historical architecture, can employ the stratigraphic forms to superpose itself on preexisting elements and become one stratum more in the building’s complex existence without erasing the traces of the preceding phases. Knowledge of the stratigraphic forms enables the identification of

Hypothetical plan of the construction periods of the bridge at La Pobleta de San Miguel (Villafranca del Cid, Castellón)

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the key points and traces in the building to be protected and conserved by restoration, and the design of the restoration project as an addition to the construction history of the existing structure. Restoration of this form can now be seen as a series of actions that add history to the building without eliminating or hiding the history of previous stages. The difference in this case lies only in the way in which a single action is carried out: completely pointing masonry represents the loss of stratigraphic data, whereas selective pointing, applied only to the gaps, will conserve the historical material and meet the objectives of decoration, material conservation and structural efficiency. The practice of stratigraphy will develop in the project architect an increasingly sensitive approach that examines the forms of construction, the building materials and techniques, and the traces left by tools and instruments. This sensitive approach to material history appreciates differences, the multiplicity of construction solutions, the complexity of history, the passage of


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time that ages materials. The restoration project benefits from this sensibility, which can conserve the matter of architecture in order to guarantee history, a guardian of memory and a witness of passing time.

Application to traditional architecture The above reflections are perfectly applicable to traditional architecture, where the material history is no less important or interesting than in monumental buildings. Furthermore, in the case of traditional and vernacular buildings, the material study is normally the only way of discovering the building’s history, which is only rarely present in written accounts. In traditional architecture, it is difficult to produce an absolute chronology of the building’s construction phases, though it is possible to identify the phases of its material history and different periods of use. The years of occupation of the traditional building can in many cases be counted in the periodic layers of whitewash stratified in its walls. There are other particularities to be taken into account when conducting a stratigraphic study of vernacular architecture. Firstly, traditional architecture has a tendency to continue its techniques and forms of construction due to the specific relation between traditional architecture and the materials of the place, the landscape and climate, and local culture. This continuity hinders the identification of different construction phases, which are often characterized by the use of the same materials and techniques for long periods of history. In these cases, where bonding, stones, finishes, etc., tend to be homogeneous and continuous, the observation of mortars and stratigraphic relations can help to distinguish different construction periods. This involves a visual inspection and calibration in accordance with existing parameters. Appropriate parameters also have to be found in the case of dry materials, very widespread in traditional architecture (dry stone, timber, straw, etc.), in order to identify differences and the form of architectural stratification. The architecture stratigraphy method is sufficiently flexible, or should be, to adapt to different situations that may arise depending on the type of materials or techniques used. Secondly, in traditional architecture there is a widespread practice of continuing maintenance, in some cases involving the replacement of entire parts, such as roofs of plant matter (timber, straw, etc.). This practice makes it difficult to exactly identify the number of times the element has been replaced. In these cases, it may be advisable to accept periodic replacement as a historical fact rather than trying to decide how many times it has occurred. The stratigraphic study of vernacular architecture can contribute a series of highly interesting data for knowledge and assessment. A detailed knowledge of construction techniques, history, forms of

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The mortar clearly indicates the insertion of the window into a pre-existing wall

The mortar shows that the wall on the left is built against the wall on the right

Restoration of a floor with the application of criteria to simultaneously differentiate and integrate the original features

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use and wear will further knowledge of its existence and, therefore, its protection and conservation. The stratigraphic study applied to traditional architecture, at first sight exaggeratedly complex and costly, can be carried out correctly and rigorously with little effort, provided the architect, archaeologist or technical architect has specific training and a skilled eye in the careful observation of the materiality of architecture. In these cases, it is a question of creating in the observer a stratigraphic mentality that can pinpoint the keys to the building’s history and conduct the project with a view to conserving the material witnesses of traditional culture.

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Timber element salvaged from panelling, with two types of groove into which the complementary pieces are fitted

Panels of polychrome coffering with two coats of paint and the traces of its new and different position

Continuity in construction techniques

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The colour study, the first step in rehabilitating a façade

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Ramon Graus Architect Professor in the Department of History and Theory of Architecture, School of Building Construction of Barcelona (Technical University of Catalonia), Spain Cristina Thió Fine Arts graduate Restorer with the specialist company CHROMA (Barcelona), Spain 4

The tourist guides might insist in showing us a traditional Mediterranean architecture that is pure white, but we must not let them delude us too—it is also other colours. It may well be Andalusia white (Spain) because a Spanish king of old ordered that it should be so for reasons of hygiene; a house in the Maghreb may have white-framed doors because its owner has returned from hajj, but the architecture of the Mediterranean is bluish in Chaouen (Morocco), bright greens, blues and reds in Burano (Italy), earth-toned in Siwa (Egypt), yellow in Tuscany (Italy)... It is also true that it cannot be simple any colour, because not all pigments stand up to the elements. Furthermore, the pigments used have a very small range that can resist the caustic action of

lime (they need to be resistant to light, air and pollution). Only inorganic pigments (minerals) can tolerate damp and high temperatures. The tradition range includes, for example, blue (the copper sulphate used traditionally to whiten the wash), as well as “Saint John’s” white (calcium carbonate), black, ochre, green earth and others. The colour of the façades can be determined by the characteristics of the construction material (colour of the rammed earth, of stoneware, of brick) or by a layer of a coloured coat or rendering (the colour of a paint, such as fresco techniques using lime, casein or mezzo secco, or the colour of stucco). We might go as far as to say that there is always colour in architecture. Colour distinguishes traditional architecture with the changes in

Girona (Spain), Agios Artemios (Greece), Cagliari (Italy), Vic (Spain), Lefkara (Cyprus), Kairouan (Tunisia).

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Tool 4 Making the graphic survey of the building The colour study, the first step in rehabilitating a façade

hue of its walls, but it also draws on frescos that imitate marble cladding, highlight openings or in some cases emphasize orders or imitate cultivated architectures (trompe l'œil), and distinguishes a house from its neighbours or causes it to merge with them, depending on the context. The logic of colour in traditional architecture does not exactly obey our scale of present-day values, based on readings of Ruskin and Viollet-le-duc, in which beauty in architecture is the synonym of truth and sincerity. In pre-industrial society, it was usual to coat or render a wall in order to protect it and give it distinction—what Professor Paolo Marconi has referred to as the “sacrifice layers”, a layer that protects a wall of brick, stone or rammed earth that is replaced with no concern for architectural sincerity when it begins to deteriorate. It is also a coloured layer that often imitates other materials, such as when stones are painted "stone colour", a brick wall is stuccoed imitation brickwork, marble-effect stucco, etc. When rehabilitating a building, a colour study should be conducted by as broad-based a multidisciplinary team as possible (architects, historians, conservators-restorers, geologists, chemists, photographers, etc.). The study has to obey a given methodology in keeping with the heritage values of the work and the economic possibilities of the intervention.

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Original 18th-century elevation for the building permit. Barcelona, Spain.

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3. 4.

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Oblique lighting for a photographic scan of façades with a relief finish.

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A historical study provides the information needed to understand the characteristics and peculiarities of each construction (see the section on historical studies in this publication). A scientific examination precisely determines the constituent materials of the works and the technique used, diagnoses alterations and their causes, and selects the most suitable conservation methods, whether preventive or restorative, and the ideal products to be implemented. It will begin with a visual or organoleptic examination (materials, techniques, measurements, appearance, possible interventions, additions, alterations) of the building. Take photographs once the scaffolding is in place. Photography is very important in documenting works.1 Conduct an architectural study of the work: take measurements, draw elevations and sections to obtain the necessary graphic backup to represent the pathologies and the condition of the surface layers (see section on geometric survey in this publication). Have a team of conservators-restorers carry out cleaning tests to find out what is hidden beneath the surface layers of pollution and identify the materials and techniques used and their state of conservation. This process requires mechanical methods (scalpels and brushes) and chemical methods (solvents and dressings). Take samples and conduct microchemical analyses to


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identify pigments (basically studied using the drop method since the early 19th century) and chemical analyses to determine the nature, composition and qualities of a given substance. Establish rigorous criteria (guidelines for action) of observation with a view to safeguarding the integrity of buildings’ cultural values. Without a theoretical basis and knowledge of the work, in the form of material and images, any intervention, despite using the most advanced techniques and products, may be open to error.

To help define the colour of a façade we need to conduct a cleaning test. Once the test has been carried out, we can see the colour beneath the dirt, identify the pigment in question and the ageing it may have undergone due to the effects of pollution, damp and the passing of time, and deduce the original colour. Using this method, the analysis mentioned above and the Munsell method (see below), it is possible to determine with a fair degree of precision the original colour or colours of the façade when the building was constructed. We have to take into account all of these factors when drawing up the colour report, because it also helps to identify the materials

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and techniques used, since an organoleptic study is not always enough to reach entirely reliable conclusions. It is vital to consider the exterior rendering of the building, which gives it presence and character. Among many other questions, the colour study of a façade seeks to answer the following: what colour is the present-day façade? How are the colours combined? Might there at some point have been others? Is the colour of the façade in keeping with its architectural style? Might it present partial or complete repainting of the elements in the façade? Naming the colour The answer to the first question has to be the name of a colour— red, for example. However, we are all aware that there are different kinds of red. We could be more specific and call it cadmium red, in reference to a specific oxide, but it could still be more or less watered down. This is why a method is needed to establish a colour reference. Here, we will refer to one that is not too sophisticated, as it does not require specific monument restoration tests such as those that use colorimeters or laboratory analysis to identify the colour. We propose a visual analysis by comparison with a Munsell Atlas. The Munsell System2 is based on identifying a colour on the basis of the visual perception of small differences visible to the human eye

Detail of the elements in the original façade.

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from a colour wheel featuring equivalent colorimetric intervals. The Munsell system specifies colours based on three attributes:

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Hue: attribute of perception that makes us see an object as green, red, etc. Lightness or value: attribute of perception that sees an object as lighter or darker. Chroma: attribute of perception according to which an object has a certain degree of purity of colour with regard to its degree of lightness. To determine the colour of a façade, the correct procedure is to isolate the colour to be studied on the wall with a neutral grey surface (such as those used in photography) to prevent interference caused by surrounding colours, and compare it to the chart to find the nearest colour. In this way we would call our red

Tool 4 Making the graphic survey of the building The colour study, the first step in rehabilitating a façade

2.5YR 6/8 (Hue Value/Chroma). There are in fact two Munsell colour charts: the Munsell Soil Colour Chart, used to compare matt hues, and the Munsell Book of Colour – Glossy Finish Collection which serves to compare glossier hues. Combinations of colour Generally, a façade is not painted a single colour. Various colours are used to highlight the elements in the façade. Therefore, the colours are combined in the façade according to a given logic that has to be studied. An initial list of elements to be identified in a façade might be: It is also important to remember that some façades may include fresco or sgraffiti, or ornamentation that has to be documented

Background Reliefs Cornices Façade

Fascias Pilasters Bases Eaves Frames Jambs Sills

Munsell Soil Colour Chart.

Arcades Openings

Mouldings Capitals Railings Balconies Balcony soffits Frames Windows Balconies

Joinery Galleries Doors Blinds Railings Metal fittings Colour combinations (background, border, openings) from the colour plan for the Eixample district in Barcelona, Spain.

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Grilles Locks and fittings


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A history of layers of colour However, colour on façades also ages and, depending on the pigment used, it may have been faded by the sun, washed out by rain or darkened or toned (not necessarily darker) by urban pollution. For example, with pollution, white lead turns black. In order to identify the original colour of the façade, it has to be

compared at those points where it has been maintained with fewest changes, for example, just beneath the balconies, inside jambs and lintels, underneath cornices, etc. We are also aware that due to the lack of resistance of the paint itself, the building will have been repainted. The most easily accessible part, for example the ground floors, will probably have been repainted most times. If the different layers of paint can be removed with a scalpel, they should all be documented, in order to understand the reason for each colour in each period, not just the first coat. If the building has a combination of colours, an attempt should be made to relate each colour to those of the same period. By exfoliating the painted surface, we will discover the colour the façade was originally painted, but it is also necessary to decide

Stratigraphic approach.

Cleaning layer of the façade.

Colour test.

Tracing of graphic motifs for templates.

(traced and studied iconographically) for subsequent recuperation as appropriate. The colour may also be provided by the use of tiles, terracotta and stucco or stone bas-relief, which also have to be studied. In order to reach reliable conclusions as to the type of colour used for each element, knowledge is required of the different artistic periods and the combination of colours most used in each.

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Tool 4 Making the graphic survey of the building The colour study, the first step in rehabilitating a façade

whether the colour to be restored is the original or, conversely (with the knowledge of the different layers of paint provided by exfoliation), another of far higher quality than the original. A thorough study of the building’s different layers of colour will help us to decide which layer to safeguard or restore, according to the style of the building. Finally, we also have to bear in mind that we cannot “remove” from the colour the effects of ageing or toning it may have undergone due to pollution and damp or the passing of time. The objective of restoring a façade should not always be to leave the façade as it was initially. In the project phase, we have to decide whether to recover its original appearance or revitalize the moment of its highest quality. It is important to stress that leaving on view the evolution and changes that have occurred to the façade can give the restored building greater value and authenticity, at the same time providing living information of the historical and artistic developments of urbanism.

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The texture of the surface or the angle of the sun’s rays modify our perception of the colour of a façade. Arbúcies, Spain.

Chipped façade showing changes in colour of the building according to the tastes of each epoch. Nicosia, Cyprus.

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The influence of texture on colour When sunlight strikes a coloured flat surface, some of the light is absorbed and the rest is reflected. It is this reflected light that the eye perceives as colour. However, a rough surface produces shadows in the micropores of the surface and the light reflected is less, so that the eye perceives a different colour. Façade colour is therefore closely associated with the technique used to apply it and its support. This is why, for example, the same colour applied to smooth plastering will be apparently lighter than on roughcasting. It is essential for the colour study to document the technique used and reflect deliberate (or other) changes in the roughness of the wall (for example, the background may be rough while the fascias and frames are plastered). It may also be that the passage of time and the fading effect of rainwater have made a surface both rough and uneven. We will have to decide whether this trace of time should be “erased” or maintained. We favour maintaining it in order to avoid false historicism in the restoration. Remember that traditional whitewash over lime fresco has a characteristic glaze, a very particular transparency of the support which no plastic paint is capable of reproducing, due to its covering power. Colour in context The context of a façade is space and time. The time is historical and artistic. The space is that of the street or the square in which it stands and, at another scale, the district and the city in which the building is located. For this reason, the study should also include information about the colour of the neighbouring façades (background, fascias, bases, frames) and those of the entire street or square (dominant


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colours). The local council may also have produced a colour chart for the town or city. In this case, it will be necessary to check whether the colours found coincide with the municipal colour chart and, if not, to find out why and to justify the need to adapt to the official chart or consider the building as a well argued exception. State of conservation Finally, the study has to reflect the state of conservation of the finishing coat and the underlying support, with a view to recommending conservation, consolidation and total or partial renovation. Below is a possible outline for characterizing the skin of the wall and its lesions.

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Material lime stucco

sgraffito

polished

Lime stucco

smooth

rough

Sgraffito

layers

colours

Polished

smooth

marble effect

sgraffito

Fresco

prepared grounds

in full

al secco

Tempera

with size

with casein

with egg

Cladding

stone

marble

slate

Timber

sheathing

strips

Ceramics

floor tile

adobe

stoneware

Plaster

mouldings

reliefs

sculpture

Paint

traditional technique

new materials

Colour

correct

dirty

smooth

Kick Strip Base

fresco

tempera

latex

tessera

others:

worn

faded

washe

marble effect

strips

panels

scenes

stone

timber

mortar

paint

stone

timber

mortar

paint

Cornice

no cornice

paint

Relation to Openings

continous

discontinous

global

correct adherence

regular/deficient

poor/cracked

whole:

intact

fragmented

fragmented:

complete

incomplete.....% loss

Partial Dimensions Surface Dimensions Design Layout Theme

Main Field

Complementary materials Site Map of Location State of Conservation Physical Integrity

broken edges

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Surface layers. Previous intervent Support

perforations

removal

Surface layer

number of layers

colours

Type of intervention

respectful

free interpretation

destructive

fresco

al secco

oil/enamel

tempera/encaustic

Varnishes

shellac

wax

glues

oil

Paints

polyurethane

nitro

synthetic

acrylic

Typology

pine

oak

walnut

cedar

others

Technique

stained

enamel paint

wax

oil

lime

Material

iron

bronze

brass

lead

Decoration

incisions

repoussé

painted

Profile

smooth

moulded

Construction

wrought

cast

State of conservation

good

average

poor

terracotta

faience

glazed

good

average

poor

Support

microfissuring

fissures

cracks

Concretions

salts

black scab

calcareous

Biological attack

fungus

lichens / plants

fauna

excrements

Action humaine

vandalism

graffiti

old

recent

Polychrome layer

pock marking

dust

Surface layer

fumes

dust

grease

rusted varnish

darkened repainting

dripping

detachment

Materials used

Polychromy 4

Painting procedure Pigments

Timber Colouration

Metal

others:

Ceramics Type Techique

enameled

stoneware

losses

hollow

porcelain

Colour On-site installation Situation State of conservation

Pathologies

Darkening

repainting Consistency

dusty

loss of colour

Crazing

premature

Due to age

Chemical alterations

of the pigment

of the aglutinating agent oxides

Adherence / cohesion

correct

deficient

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cracked

others: paint splashes

broken edges

stains


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Graphic representation of a dirty façade surface. Barcelona, Spain.

Graphic representation of the lesions in the façade’s substratum. Barcelona, Spain.

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Colour for a faรงade proposed on the basis of a study.

This information should be recorded and then represented in an elevation of the faรงade showing damage. On the basis of all of this information, a diagnosis can be determined and a solution chosen in keeping with the overall intervention.

1 There are various useful photographic techniques for documenting and studying the surfaces requiring treatment, such as macro for details; photography with oblique lighting, which highlights irregularities or unevenness in the surface; infrared photography (IR), which allows us to observe the underlying pattern in some places and the thickness of repainting, and ultraviolet photography (UV) is useful to a study of the surface and repainting, and recognising certain pigments. Finally, X-rays (XR) serve to identify inorganic materials. 2 Albert Munsell (1858-1918), artist and art lecturer, devised a system (A notation of colour, 1905, Atlas of Munsell Colour System, 1915) for reliably establishing and naming colours.

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The applications of digital photography

Photograph of the façade before rectification.

Photograph once rectified.

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Joaquín Montón, Technical architect Lecturer in the Department of Architectural Technology II, School of Building Construction of Barcelona (Technical University of Catalonia), Spain

Since its invention, photography has been a very useful tool in the world of architecture and particularly in the field that concerns us here, that of rehabilitation. In the past, architects used engravings and paintings to find information about the original condition of a building or element requiring restoration, but the photograph naturally took over, generally offering a more faithful likeness than the interpretations of painters and engravers. We are witnessing an important and interesting moment in the history of photography: the transition from traditional or “chemical” to digital photography. What at first sight might seem to be simply a change in support is in fact a revolution that is affecting all activities related in any way with photography. Proof of this change is the fact some major manufacturers have stopped producing cameras for film except some top-range professional models and simple pocket cameras. The same goes for film and photographic paper manufacturers. The former have drastically reduced the list of emulsions available, and traditional paper manufacturers can be seen to shift their production towards the “photographic” printer paper market. It must be said that traditional photography can achieve practically the same results as digital—though the processes are more complicated, requiring much more time and work, and practically always much more expensive.

Graphic mapping of the façade.

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Tool 4 Making the graphic survey of the building The applications of digital photography

The advantages that digital photography represents for our work include: Immediacy. We can see the result of each photograph and, if we are not satisfied, we can take another, changing the settings or the viewpoint, and thereby avoiding the need to return another day. The increase in the number of options for developing photographs. They can be printed at home with a photographic quality printer or taken to a laboratory for enlargement. Laboratories provide professional quality prints and we can even send the files over the Internet, saving ourselves a journey. Probably the biggest advantage for many users is the possibility of editing the files using specific programs for different needs. We can retouch our photographs, correct defects such as aberrations of the lens, compensate for slight errors of exposure, etc. Added to these advantages are the constant increase in the capacity of memory sticks and a major fall in prices, allowing us to take a large number of photographs with little affect on the price. We can therefore individually photograph as many details or parts of a building as we like, since quantity has ceased to be a problem, either technically or economically. To prevent so many images becoming a problem, it is necessary to use an image databank management program. Such a large number of photographs could otherwise become useless, making the collection of images ineffective. Not just any image viewer will do; the program must have a good graphic interface and, most of all, an efficient database application that will assign each image as many data fields as necessary and manage them effectively.

This type of database, or photo bank, has the advantage that the images occupy hardly any physical space, particularly if we compare them to filing cabinets full of photographs on paper. They also have the great advantage of distance access and consultation by means of a simple Internet connection. In addition, should we need an image, we can download it as a digital file and process it as we wish. It is also a useful tool for reproducing with maximum fidelity elements requiring subsequent work, such as a sgraffito, mosaic or fresco that needs restoring. In all of these cases, we are particularly interested in the colours of the reproduction. Digital photography adapts perfectly to these tasks provided the computer used complies with some basic requirements. As well as a photograph-editing program, we need a computer that provides the right conditions for working in colour. This requires a wellcalibrated quality monitor and knowledge of the colour profiles of both the camera and the printer in order to work with real colours and, ultimately, transfer them to paper. If we have the above equipment and know how to use it, the result can be fully satisfactory. Otherwise, it is difficult to guarantee the precision of the colours. We have to take into account one of the limitations of digital photography, the impossibility of reproducing on paper some colours that are visible on the screen. However, this limitation is not exclusive to digital photography; it also happened when using the traditional method. Where digital photography has become an irreplaceable tool is in mapping the planes of building faรงades, for example when cataloguing historic centres or buildings where it is difficult to take

Database for managing an image bank.

Nikon PC camera with perspective correction lens.

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sufficient measurements to draw them precisely. Photographic rectification is the system used. By taking a photograph and establishing at least four non-aligned points marked out by two real measurements, we can rectify the front plane at scale. Then, using this photographic elevation, we can produce the plans of the façade, bearing in mind that we can take measurements from the photograph. The example shown in the illustration was produced by the Architecture Heritage Workshop of the EPSEB using the Homograf program. Likewise, with the help of graphic restitution programs we can generate perspectives of buildings from pairs of plans. Before digital tools were available, with traditional cameras it was advisable to take the photograph with the optical axis of the camera as perpendicular as possible to the plane of the façade and correct the perspective in the enlarger or work with cameras with bellows (Linhof, Sinar, etc.) or perspective correction lenses (Nikon PC, Canon TS-E lenses, etc). To prevent this seeming an apology for digital photography, below are some of its drawbacks. Although digital photography equipment is presented as being cheap or at least affordable material and hailed as having democratized photography in that it provides access to many people who would not otherwise dare to try it, the cameras are, in general, more expensive than the ones they replace. A good traditional reflex camera normally lasted many years. Its replacement, the digital reflex camera, tends to be more expensive

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and, unfortunately, their manufacturers make them obsolete in the space of two or three years. The new ones have more pixels, a faster processing speed and increasingly sophisticated programs. Digital cameras are, in general, very susceptible to falls and rough treatment, highly sensitive to atmospheric agents, humidity, extreme temperatures and, above all, dust, which can cause serious problems. Traditional technical services no longer repair this kind of camera, which has to be taken to the brand’s official service, which no longer carries out minor repairs. They normally replace the camera if it is under guarantee and, if not, the quote for repair (a set price, whatever the problem) usually prompts the owner to change cameras. We miss the hardy cameras that stood up to almost anything, even working without batteries, such as the Nikon FM or similar.

Sinar mobile back for architecture photography.

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Structural damages in Traditional Mediterranean Architecture

César Díaz Gómez Doctor of Architecture Professor of the Department of Architectural Technology I, School of Architecture of Barcelona (Technical University of Catalonia), Spain

The behaviour and durability of the structural elements of traditional housing are closely related to the materials used and the means of construction of the urban and rural surroundings in which they are set. The departure point is, then, knowledge of these materials and means of construction in order to start the process of diagnosing the alterations and damage of all kinds presented by the buildings. It is also useful to have as much information as possible about modifications and interventions of all kinds to have affected the building over the years and even the different uses to which it has been put. It is advisable to have a graphic or written representation of the information compiled on plans, sections and elevations of the buildings, with a view to relating the location of damage to the position of the various structural elements and the main construction, including partition walls. It is also recommendable to take note of modifications over the years in distribution and volumes in the form of extensions to the height or in the floor plan, as this will aid an overall, integrative understanding of the construction, which is of particular interest in the case of old or historical buildings. Bearing all this in mind, below is a diagnosis of the lesions most frequently found in the various construction elements that comprise the structural systems of these buildings, with particular attention to those that directly support the dead or live loads represented by static, wind or earthquake load—that is, the walls, pillars and foundations, as regards the vertical elements, and the structural floors, vaults and domes as the most common covering elements.

those transmitted by the structural floors and roofs, and those generated by prevailing winds, directing them to the foundations, generally comprising rigid footing of a shallow depth and similar in width or slightly wider than the wall. They are thick enough to provide a solid base, since they are used for constructions of two or three storeys at most, adopting geometrical arrangements in the form of closed volumes that brace each other to varying degrees, in accordance with the distance between them and the rigidity of the wall-floor engagements. On the basis of these principles, when one or more of these characteristics is insufficient or anomalous, lesions will appear in the form of cracks, fissures or distortions whose formation, location and dynamic constitute the body of useful data for diagnosis. When referring to thick walls, we take for granted the fact that they are single-facing walls, solid throughout, but it is advisable to remember when diagnosing these walls that they may not be homogeneous in section, particularly in the case of masonry walls. This is the case not only of Roman-style walls, with in-fill material between two masonry facings, but also of many others built apparently with a single facing, in which the plumb conformation of faces with larger stones generates internal patches that are more disintegrated and subject to distortion and, therefore, less resistant. It is also important to mention the fact that the types of fracture in most thick old walls endorse a sufficient correlation with the elastic model in many of the most common cases, though in others more detailed knowledge of the characteristics and the intervening actions is needed to conduct diagnosis. In order to facilitate the description and analysis of the most usual structural lesions, I distinguish between those present and visible in the same plane as the faces of the walls and others that form in central sections of the same walls or generate distortions transverse to its faces. Starting with this initial distinction, the list continues with the different variations, listing the principal characteristics in each case.

1. Structural damages in buildings with thick walls The vertical structure of the buildings in question is usually made up of walls built using local materials. With the single exception of walls built using plant matter or timber frames, the walls of these buildings are thick, rarely slender, built of earth, brick or stone as the basic material, using ancestral techniques involving moulding (in the case of rammed-earth walls), earth- or lime mortar-based agglomerating agents to bond the various pieces, though the various units (in this case stones) may also simply be fitted together to produce dry masonry. In mechanical terms, walls built in this way are characterized by being self-supporting elements, capable of absorbing the loads generated by their own weight,

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1.1/ Coplanar damages in the wall faces The most specific characteristic is that the fact that the damage, in the form of cracks, fissures or crushing, shows in the superficial faces, and usually runs right through the section of the element, thereby differing from most non-structural lesions. 1.1a/ Damages caused by excess compression in a large stretch of the wall

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The position of the fissures or cracks coincides with the direction of the isostatic lines of compression corresponding to a vertical element of a flexible, homogeneous and isotropic material, receiving the vertical load of its own weight and that of the structural floors, uniformly distributed. The breakages form mainly in the parts bearing the greatest load, coinciding with the lower part of the wall and, as applicable, in the solid areas of concentrated load between openings. This indicates higher levels than admissible of compression in the fractured area, with very differing effects to the safety of the building, depending on the capacity to redistribute tensions in the area of the wall or the wall system as a whole. In irregular coursed masonry, it comes as no surprise that one of the first symptoms of fracture should be the crushing and disintegration of the mortar in the horizontal bonds when the elasticity of the mortar is much lower than that of masonry or bricks, which tends to occur in older walls. This phase is followed by the progressive vertical breakage of the masonry induced by the tensions of horizontal traction in the contact between the mortar and the masonry, ultimately forming a collection of continuous vertical cracks. In random rubble masonry, this process, if it does occur, is not so obvious, though the cracks tend to zigzag along the mortar bonds, following the same pattern. The difference in vertical load between the two stretches of the same wall is indicated by the fracture of vertical sections coinciding with or close to the change of load, marking a vertical crack or succession of sloping cracks with a common vertical axis and a slope in the direction of the tensions.

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1.1.b/ Damages caused by concentrated loads The fissures slope away from the sides of the element generating this load, usually a beam or joist, or run vertically beneath it. As in the previous case, the degree of gravity will depend on the possibility of redistributing the tensions of the element affected, which is high in most cases though this is not the case of freestanding pillars, which generally require reinforcement.

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1.1.c/ Damages caused by insufficient rigidity in elements of union The distortion of elements that, theoretically, taking as a reference the elastic model, are taken to be infinitely rigid, is the cause of the formation of singular patterns of fracture, different to those produced in other situations. By way of example, the first diagram shows the fissures induced by a distorted timber lintel, allowing the zonal decompression of the wall with the formation of fissures marking the discharging arch and the effect of the concentrated load on the joist. The second shows the effects caused by the distortion of the foundations beneath the concentrated load of the faรงade wall, generating in it fractures caused by shearing or flexion depending on the size of the openings and the ductility of the materials in the wall..

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1.1.d/ Damages caused by differences in load between bracing walls A vertical fracture will frequently form in a corner formed by the bearing wall and the bracing wall. The loss of continuity in the wall system represents a reduction in its rigidity, with effects that must be evaluated in accordance with the incidence of horizontal wind and earthquake loads..

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1.1.e/ Damages caused by differences in rigidity between the component materials of mixed walls In coplanar walls built of two types of masonry or materials with different degrees of rigidity, one of them—the most rigid—forming apparent pilasters and the other forming the wall proper, cracks may appear as a result of shearing generated in areas impeding the distortion of the least rigid material or masonry. These breakages, generally in thick walls, do not have serious effects on their equilibrium, and are typical of walls that combine brick masonry with rammed earth, or irregular- with irregular masonry.

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1.1.f/ Damages due to differential settlement of the foundations

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Earth movements are one of the most frequent causes of fissuring and cracking of traditional walls. These movements may be produced by multiple causes, some of which are intrinsic to the terrain (wetting of cohesive soils, unstable hillsides, etc.), and others related to the characteristics of the building’s existing foundations or intervention in adjacent buildings. Generally—though not always—the damage is progressive, providing information about its evolution and the adoption of appropriate preventive measures. The movements are shown in the form of the fissures illustrated in the figures below, according to the type of movement (descending or slipping), part of the building affected (corner or centre) and certain of the building’s characteristics (blind wall or wall with openings). As explained above, these outlines are based on the hypothesis that walls behave mechanically as elastic and rigid elements, with little plastic distortion prior to the moment of fracture, as they are also homogeneous and isotropic. Obviously, the closer the wall’s characteristics to this model, the more valid the references to the types of fracture suggested by the elastic model, though it is necessary to bear in mind that the most probable points of fracture tend to coincide with the position of weak points in the absorption of the traction tensions generated by the movement. This is logical if we consider the scant resistance to this type of load of the materials that make up the walls in question here.

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Tool 5 Understanding structural damages Structural damages in Traditional Mediterranean Architecture

1.1.g/ Damages caused by seismic movements Traditional architecture constructions built using earth, stone or brick walls, particularly the first two, do not offer much resistance to seismic movement, due to their scant resistance to traction and shearing and their limited ductility in response to the multidirectional loads introduced by these movements. The visual symptom that most commonly identifies this lesion is the presence of cross-shaped fissures in the stretches of wall between openings, indicating breakage caused by shearing of these stretches of wall as a result of being shaken in two directions (right-left, horizontal-vertical), practically simultaneously, that characterizes seismic movement. Other visible effects, such as fissures in sections with a change of inertia or due to thrusting caused by seismic activity are also frequent, as is the formation of invisible damage in the inside of the walls (detachment, microfissuring, etc.) that reduce their bearing capacity. Evidently, evaluation of the seriousness of the lesion will require a specific analysis of the damage to each building. 5

1.2/ Damages in the transverse plane to the wall face This type of lesions is characterized by being invisible in the outer face of the wall or manifesting itself in the form of distortions transversal to the outer face.

1.2.a/ Vertical breakage in interior sections of the wall Excess compression in a thick wall can generate a vertical internal fracture which, following the isostatic line of compression that passes through the point at which the materials’ breaking tension is reached, tends to gradually divide the wall into two halves, thereby making it thinner and reducing its bearing capacity. This type of breakage affects many walls that do not have homogeneous interiors, with weak internal sections as a result of the positioning of stone masonry or ceramic units according to the fixed references of the vertical planes

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of the faces. This is the most dangerous form of fracture of those listed here, since its presence and progression inside old walls cannot generally be seen, hence the possibility of collapse without necessarily undergoing a perceptible phase of distortion. Its presence and discovery, both in walls and in freestanding pillars, calls for the short-term adoption of measures to reinforce the damaged elements. 1.2.b/ Collapse and bulging of façades These phenomena are generally the product of long processes of distortion caused by the prolonged effects of vertical or horizontal loads on the wall’s materials, along with the effects of its rheology, leading to changes in its mechanical characteristics over time. Advanced phases of distortion tend to call for props or other cautionary measures. Thrusting of the roof, torsion in the foundations or the effects of damp and temperature are the most usual causes of collapse, whereas the rheological processes of slow distortion subject to loads transmitted by the roof and the structural floors are the most common causes of bulging. 5

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1.2.c/ Thrust of the vaults Vaulted elements generate thrusts at their meeting point with the perimetric walls, which have to be counterbalanced by the thickness and mass of the latter, sometimes with the assistance of buttresses. Insufficient counterbalancing of thrusts will produce cracks and distortion that may affect not only the walls but also the vault, which is decompressed as a consequence.

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2. Structural lesions in the structural floors, vaults and domes of buildings with thick walls The most usual covering element in Mediterranean construction is the structural floor, comprising timber joists and beam fill of very varying materials: reeds, timber sheathing, ceramic tiles, small timbrel vaults or a binding agent and agglomerate, etc. Vaults and domes, conversely, are less usual and more singular in their application, built using the same materials as the walls and construction techniques specific to each place. 2.1/ Damages in structural floors of timber beams and joists In timber beams and joists that form structural elements supporting the floor, there are three types of lesions with different characteristics: distortion, biotic attacks and cracks, also called shakes in the case of timber. 2.1.a/ Distortions It is usual in old buildings to find structural floors with a high degree of flexion due to the flowage experienced by the constituent timber elements. Flowage, which is the quality of a material to progressively distort under the loads it bears, whether or not these loads increase, is a typical phenomenon of timber when it works under flexion, and leads to a reduction in the bearing capacity of the element of which

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it forms part. This element should be evaluated in each case according to the mechanical characteristics of the type of timber, the load borne by the floor structure and the existing deflection.

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2.1.b/ The presence of cracks Although cracks are usually the result not of the mechanical action to which the floor is subjected but of causes related to the drying out of the timber or cycles of ambient humidity, it is always worth checking their origin and evaluating the repercussions on the inertia of the elements affected. If they are caused by mechanical action, their presence may be a symptom of situations of breakage and collapse.

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2.1.c/ Biotic attacks The presence of rot produced by various types of fungi or wood-eating insects such as termite or woodworm leads to a reduction in the working section which, as in the previous case, must be specifically evaluated in each building. Detection of the location and extent of damage is, then, an absolutely necessary part of the information required to diagnose these elements.

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2.2/ Damages in vaults and domes The mechanical and structural behaviour of vaults is habitually recognised as the superposition of the curved directrix of the element with the corresponding line of pressure. The greater the distance between this line and the position of the directrix, the greater the risk of fissuring or crushing, as these points then coincide with the areas subject to the maximum tensions of traction and compression. The types of fracture found in vaults differ substantially from those found in domes, since the latter are authentic spatial structures whose interpretation necessarily requires a complex three-dimensional approach, which explains some of the classic models of breakage presented. It is common in both elements for the origin of damage to lie in decompression as a result of movements of the walls, pillars or pilasters that receive their thrust, whether due to the collapse of walls or sinking caused by differential settlement of the foundations. Other possible direct causes of lesions are excess load or the weakness of built elements. The diagrams illustrate the most usual forms of fracture.

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5 3. Particularities of the behaviour of structures with timber framework The mechanical and structural behaviour of the framework walls of traditional construction differs substantially from that of the thick walls referred to in previous sections. In this case, the principal resistant elements are the linear pieces of timber that make up the framework, whereas the walls of rammed earth, adobe or brick fulfil the subsidiary role of preventing buckling, in any case absorbing a random percentage of the forces of compression. These are, then, porticoed structures braced by solid stretches of wall. The floors usually comprise timber beams and joists supported by the elements in the wall framework or interior pillars. These are structures with complex behaviours, marked in many cases by the differences in stiffness between the component materials, the relation between the thickness of the wall and the separation between props, and the arrangement of the framework elements, which may be very varied, with a differing number of diagonal elements. In any case, an important aspect and one that is often decisive in the durability of this type of walls is the progressive deterioration of the timber in the absence of maintenance, producing a gradual loss of bearing capacity.

Bibliography Various authors: Tratado de rehabilitación. Patología y técnicas de intervención. Elementos estructurales, Departamento de Construcción y Tecnología Arquitectónica, Universidad Politécnica de Madrid, Editorial Munilla-Lería, 1998, Madrid. Various authors: Manual de diagnosi i intervenció en sistemes estructurals de parets de càrrega, Col·legi d’Aparelladors i Arquitectes Tècnics de Barcelona, 1995, Barcelona. MASTRODICASA, S. Dissesti statici delle strutture edilizie, Hoepli Ed., 1978 (6th edition), Milan.

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Seismic risk in the traditional architecture

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The geomorphic and tectonic characteristics of the Mediterranean basin cause high seismic risk in this area, since it is the western part of the Alpine-Himalayan range, where a complex collision system results from the interaction between the Euro-Asiatic plate and the African, Arabian and Indian plates. As a result, the seismic activity has been always dramatically present here, often with disastrous effects (human lives as well as more or less important damages to the architectural heritage), from the single construction and the monumental building until the historical centre and the whole environmental context (the natural and the built environment). It has sometimes compromised the historical testimony and the identity itself of a place. Then, the Mediterranean traditional architecture results as dramatically vulnerable, as it often undergoes important effects, differently in relation with the structural and material characteristics. So, a commonplace considers the masonries less resistant to the seismic action than the modern reinforced concrete structures. Indeed, the masonry, if it is well built and maintained, is able to withstand also high intensity earthquakes, as the monumental heritage has shown by facing hard proofs. This is due to the materials, the techniques and the constant maintenance, which ensured and still ensure the respect of the “Rule of Art”. Besides, more comprehensive and analytic studies on the seismic damages (because of the actual improved possibility to gather and manage information) have recently shown the “natural” capability to absorb vibrations in the masonry walls, floors and roofs, provided that they are well realised, connected and maintained. Moreover, the restoration and reinforcement of the masonry buildings, also with important cracks, allow their conservation, with just the partial loss of the original geometry. Differently, the reinforced concrete buildings have to be demolished if their geometry has changed, even if the deformations are limited. As we are going to highlight later, the particular characteristics of the earthquakes, such as the intensity and the intermittence, have prevented from understanding in depth the problem and its causes. As a result, the structural techniques and features have not been developed by the experience, as the traditional construction culture has been.

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Giambattista De Tommasi engineer Full professor in Building Refurbishment (Technical University of Bari), Italy Collaborators: research group work (Fabio Fatiguso, Mariella De Fino and Albina Scioti)

Engraving of a biblical memory earthquake: the buildings and the ground are upset according to ancient beliefs.

Building structural features and earthquakes in the history

Historically, the earthquakes were interpreted through apocalyptic and imaginative suggestions that even considered the human understanding as inadequate, because of the lack of a basic scientific approach in the pre modern culture. The missed theorization of the causes explains, on the one hand, the lack of established anti seismic structural solutions, and, on the other hand, the idea that any structure, even if solid, was not able to withstand the indomitable and threatening nature of the earthquakes (often considered as a divine punishment). Furthermore, the long term recurrence of the telluric phenomena interfered with the strengthening of a consciousness related to the seismic risk and the consequent possible cures. In fact, the destructive effects of an earthquake were progressively forgotten after few generations. The mankind has protected itself from the constant effects of the natural environment with roofs, walls, floors and uncountable expedients, progressively improved. Otherwise, it has not been able to provide good resistance of the buildings to dynamic stresses. The historical memory of the destructive event persisted in the popular consciousness, but it was burdened with superstitions and connections to supernatural events. Aristotle, one of the first philosophers of the sciences of earth, wrote that “…so, neither the water nor the fire, but the vapour would cause the earthquakes, when it flows inside what usually


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exhales outside…”1 and Seneca, in the sixth book of the Natural Issues, titled On the movement of the Earth, correctly described the effects, but he connected them to some water or air, whirling in underground caves and producing the seismic tremors. Also Plinio, in the Natural History talked about a wind into the earth to be exhaled through “sewers and deep wells2”. The explanations during the following centuries were not very different, but they are difficult to report in detail. Anyway, they all were lacking of any right intuition about the seismic phenomena. They sometimes tried to explain all in terms of magic and/or witchcraft. Besides, significant developments to define the causes of the earthquakes did not happen, even when the processes producing the collapse of the masonries were understood (we have uncountable drafts, drawings and descriptions about that). Moreover, the early enthusiastic scientific discoveries, at the beginning of the Enlightenment, created further confusion rather than solutions, as in case of electric phenomena: “… the enthusiasm for the electric phenomena leaded to think that any inexplicable event was imputed to the fluid, or the electric vapour according with the definition of that period, and the earthquakes themselves were considered a consequence of the electricity…”3. So, Valadier designed the anti seismic towers in Rimini in order to scatter the electricity of the earth in the atmosphere. However, in the 18th century, there was a qualitative leap, when scientific experiences and observations4 leaded Bottari to understand the phenomenon, in its “Three lessons on the earthquake” published in Rome: “the bowels of the earth are soaked in many spots by sulphurous and bituminous breezes that are mixed with nitre or other substances, so that they catch fire, spread in the caves where they are, break or try to break the opposite obstacles and cause the tremors of the earth…”5. In the same century, the modern seismology was born: the studies by

Mallet6, the seismograph by Mine, the scale by Mercalli to measure the seismic intensity were significant phases that cleared a way for the investigation during the XX century (since the researches by Baratta and Wegner) that finally explained the causes of the earthquakes and the countermeasures to take. As regards the technical solutions, we just underline that, since the ancient times, especially after very dramatic earthquakes, many technical and structural measures have been set. They were all interesting and more or less effective, but they always had a rapid development and a rapid disappearance, as well. In Italy, in the IV century BC, in the Greek colonies of Metapontum and Paestum, the constructers founded the buildings in trenches that were dug inside the rock and filled with sand. In the northern Syria, in the second century BC, the earth masonries had a wooden framework. After the earthquake that destroyed Pompeii and partially Naples in 63 AD, an early anti seismic set of rules was imposed, known and transmitted until the Renaissance, which avoided constructing buildings higher than two floors. By the way, a technical and structural innovation did not correspond to the normative development, except for the timber dwellings in Ercolano, whose structure was composed of a wooden framework (opus graticium) with a filling of crushed stone, mud and cane frame. However, after the dramatic earthquake that caused the destruction of a great part of Lisbon in 1755 and was perceived throughout the Europe, the strong will was felt to apply suitable measures to reduce the destructive seismic effects (even if misunderstanding the causes). For the reconstruction, some regulations were issued for the first time in the history. The height of the buildings, the width of the streets and, most of all, some structural rules for new buildings were imposed. Specifically, the walls had to be composed of a wooden framework (later named

Effects of the dramatic earthquake, Friuli (Italy), 1976.

Depiction of the earthquake in Rode, 1495. The higher circular towers of the town wall are collapsed while the slower ones still with stand.

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as “pombal cage” from the marquis Pombal who designed the reconstruction) that was able to support floors and roof, in case of earthquake. The pombal cage inside the walls was composed of a braced frame with piles (prunos) and transoms (travessenhos). The transoms were connected to the walls by a series of dadoes (maos). The upper part of the dadoes were connected by beams (frechais) each other and by architraves (vergas) and rafters (pendurias). The elastic wooden structure ensured great resistance to the building, also by means of the flexible connection dogs. The important technical solutions, previously highlighted, got to more complex applications after the Calabrian-Messinese earthquake in 1783 with a particular kind of antiseismic building typology. The “casa baraccata” described by Vivenzio7 was composed of load-bearing wooden framework with horizontal and vertical beams on piles. A significant step is taken towards a good construction rule, supported by a better understanding of the telluric phenomena. In fact, the homogeneous and unitary behaviour of the building against the seismic actions begin being ensured by steel bars inside the walls, tie beams and buttresses to better connect the structures. The ringing of the buildings was even encouraged by the authorities. In Italy, in 1854, the Bourbon government exempted the iron, employed for that purpose, from taxation. In some Italian areas, safety room were used, as well as rooms reinforced by soft iron blades that were placed between the wall and the plaster and shaped as St. Andrew cross. The

reinforced wall became very common, particularly after the earthquake in Messina in 1908. There were many versions: some of them were licensed, from the simple reinforcement by steel tie beams until modular systems, composed of hollow bricks with different shapes and slot to be tied by zinced iron threads.

18th century engraving representing an earthquake caused by exhalations of underground vapours.

Antiseismic towers designed by Valadier in Rimini.

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Value of connections for seismic resistance Evidently, in each Mediterranean region, the art of construction has specialized in order to realize masonries as well as possible, by materials that were available in loco and economically sustainable. So, a good quality wall may have different material and structural characteristics for different areas. By the way, the rules of construction are basically the same (dimension of elements, way and quality of realization, texture of faces, quality and quantity of mortars, connections and homogeneity). Particularly, the monolithic nature of cavity walls has to be achieved for the resistance to dynamic stresses. In fact, the single parts have to be connected each other to show a “box” behaviour. This condition may avoid the vertical slides that usually lower the stabilization capability of the weight against the horizontal thrust. Beyond the connections into single building elements, good connections among different constructional elements has to be globally ensured in the whole structure (wall-wall, wall-floor, wallroof), in order to reduce the deformations by the presence of


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Pombal cage model.

effective constraints and, as well, to avoid the hammering due to different structures that swing with proper period. According to Rondelet “the naturists have pointed out that in nature the bodies of the living beings are arranged so that the bones are never untied each other. In the same way, the frameworks have to be connected with the other frameworks and reinforced with nerves and ligaments; then, the series of frameworks has to be able to withstand alone and perfectly closed in its solidity, even if any other element fail”8 These “ligaments” are aimed at providing the masonry, in case of seismic action, by “box” behaviour (using a modern definition) that is the basic goal of any work to reinforce and/or improve the seismic resistance. The box behaviour, also ensured by top connections (stringcourses), may allow, on the one hand, the different resistant elements to exchange horizontal seismic stresses each other and, on the other hand, the building to produce a global reaction, based on the collaboration and the distribution of the induced stresses on all the different parts. In fact, the connections have to oppose the rotation of the walls (for instance, the building faces) and to transmit the action to the perpendicular walls so that they crack in their plane. If these connections cannot be achieved only by the normal rules of good construction, the employment of metal tie-beams could be very useful. Militia underlines that “in ancient times, the walls were well maintained by passing through with long wooden beams that worked as chains along all the thickness of the masonry so that the wall was reinforced itself and effectively connected with the other ones. The olive wood was used for this purpose, as it cannot be damaged by the lime so that it is better than the iron chains, now widely employed”9 . The effectiveness

The “hut” dwelling by Vivenzio.

of the metal tie-beams, within the good technique of construction, is referred to the capability to create or recreate a solid connection between horizontal and vertical structures. These same purposes can be also achieved by the suitable arrangement and the correct structure of the floors. Particularly, the link between walls and timber or iron floors has to be ensured, since the beams may act as both ties, by avoiding the walls to rotate towards the outside, and struts, by avoiding the walls to collapse towards the inside. Furthermore, the floors have to be enough rigid to distribute their weight on the walls uniformly and the seismic stresses proportionally to the rigidity of the resistant masonries. An effective connection between load bearing elements and walls can achieve this result, rather than the simple support that causes the unthreading and hammering of the walls.

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Shrive N.G., Sayed-Ahmed E.Y., Tileman D. (1997). Creep analysis of clay masonry assemblages. Canadian Journal of Civil Engineering, n. 24, pp. 367-379. Siviero, E., Barbieri, A., Foraboschi, P. (1997). Lettura strutturale delle costruzioni. Città Studi Edizioni.

1 (“… così adunque né l’acqua, né il fuoco, ma il vapore sarebbe cagione dei terremoti, quando accade che scorra al di dentro ciò che esala al di fuori …”). 2 (“fogne e spessi pozzi”).

Typical failure mechanisms of buildings in the historical centres (Giuffrè, 1993).

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3 A. Favaro, “Intorno ai mezzi usati dagli antichi per attenuare le disastrose conseguenze dei terremoti”, Tip. Grimaldo, Venezia 1874. (“… l’entusiasmo destato dall’aspetto dei fenomeni elettrici fece sì che tutto ciò di cui non si sapeva dare una adeguata spiegazione, venisse attribuita al fluido, o come si diceva allora al vapore elettrico, e quindi anche i terremoti venissero riguardati come un fenomeno, la cui causa era da riconoscersi esclusivamente nell’elettricità …”). 4 Carried out by Leibnitz, Kepler and Newton.

References Baratta, M. (1901). I terremoti d'Italia, 1901. Arnaldo Forni Editore.

Batoli G., Blasi C (1997). Masonry structures, historical buildings and monuments, Chapter 11 of Computer analysis and design of earthquake resistant structures – A handbook (Advances in earthquake engineering, vol. 3), edited by D.E. Beskos & S.A. Anagnostopoulos, p. 563-606, Computational Mechanics Publications. Binda L., Gambarotta L., Lagomarsino S.,Modena C. (1999), "A multilevel approach to the damage assessment and the seismic improvement of masonry buildings in Italy", in Seismic Damage to Masonry Buildings (A. Bernardini Ed.), Proceeding of the International Workshop on "Measures of seismic damage to masonry buildings", Monselice, Padova, Italy, June 25-26, 1998, A.A. Balkema, Rotterdam, pp.179-194. Carocci C. (2001), Guidelines for the safety and preservation of historical centres in seismic area, III International Seminar on Structural Analysis of Historical Constructions, University of Minho, Guimarães (Portugal), 7th - 9th November 2001, pp. 145-165. De Tommasi G., Monaco P., Vitone C., (2003) “A first approach to the load path method on masonry structure behaviour” – in Brebbia, C.A. (Eds.), Structural Studies, Repairs and Maintenance of Heritage Architecture VIII –- Wessex Institute of Technology WIT Press, Southampton (UK) – ISBN: 1.85312.968.2. Giuffrè A. (1993), Sicurezza e conservazione dei centri storici: Il caso Ortigia, Editrice Laterza, Bari. Giuffrè A., Carocci C. (1996), Vulnerability and mitigation in historical centres in seismic areas. Criteria for the formulation of a Practice Code, Proceedings of the 11th World Conference on Earthquake Engineering, Acapulco, Elsevier Science Ltd. Giuffrè A., Carocci C. (1997), Codice di pratica: per la conservazione dei Sassi di Matera, Matera, La Bautta. Giuffrè A., Carocci C. (1999), Codice di pratica per la sicurezza e la conservazione del centro storico di Palermo - Laterza, Bari. Grunthal G., Musson, R.M.W., Schwarz, J. & Stucchi, M. 1998. European Macroseismic Scale 1998 (EMS-98). European Seismological Commission, Working Group Macroseismic Scales, Luxembourg. Karaesmen, E.,Unay, A.I., Erkay, C., Boyaci, N. (1992). Seismic behaviour of old masonry structures. Proceedings of the tenth World Conference on earthquake engineering. A.A. Balkema, vol. VIII: 4531-4536. Masciari Genovese F. (1915), Trattato di costruzioni antisismiche, Milano. Rondelet J. (1802) “Traité thèorique et pratique de l’art de batir”, Paris.

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5 (“… le viscere della terra in molti punti inzuppate di aliti sulfurei e bituminosi i quali mescolati col nitro o in altra guisa prendono fuoco e si dilatano in forma che non potendo capire, in quelle cavità dove si ritrovano, inchiusi a principio spezzino o tentino di spezzare gli opposti ostacoli il che da cagione al tremore del terreno …”). 6 Mallet, “Il grande terremoto napoletano del 1857”. 7 G. Vivenzio, “Istoria e teoria de’ tremuoti, ed in particolare di quelli della Calabria e di Messina del 1783”, Napoli 1783. 8 J. Rondelet, “Traité théorique et pratique de l’art de bâtir”, Paris 1802. (“i naturisti hanno notato che in natura i corpi degli esseri animati risultano strutturati in modo tale che le ossa non restino in nessun punto staccate tra loro. Allo stesso modo le ossature saranno da riunire alle ossature, ad esse tutte da rafforzare nel modo più opportuno con nervi e legamenti; sicchè la successione delle ossature, collegate tra loro, risulti tale da resistere da sola, quand’anche ogni altro elemento venisse a mancare, perfettamente conchiusa nella solidità della sua membranatura”). 9 F. Milizia, Principi di architettura civile, Finale Ligure 1781, parte III, cap. I, pag. 102. (“gli antichi per meglio mantenere i muri li attraversavano di tratto in tratto con lunghi travi di legno, che servivan da catene, le quali prendevano tutta la grossezza del muro, che rimaneva perciò fortificato in se stesso e meglio collegato agli altri muri. Si adoperava a questo effetto legno di ulivo, che non viene come gli altri danneggiato dalla calce, e sembra preferibile alla catene di ferro, di cui si fa ora tanto abuso”).


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The European-Mediterranean Seismic Hazard Map

María-José Jiménez Doctora investigadora Institute of Earth Sciences “Jaume Almera” – C.S.I.C., Barcelona, Spain

Seismic hazard is defined as the probable level of ground shaking associated with the recurrence of earthquakes. The assessment of seismic hazard is the first step in the evaluation of seismic risk, obtained by combining the seismic hazard with local soil conditions and with vulnerability factors (type, value and age of buildings and infrastructures, population density, land use). Frequent, large earthquakes in remote areas result in high seismic hazard but pose no risk; on the contrary, moderate earthquakes in densely populated areas entail small hazard but high risk. Minimization of the loss of life, property damage, and social and economic disruption due to earthquakes depends on reliable estimates of seismic hazard. National, state and local governments, decision makers, engineers, planners, emergency response organizations, builders, universities, and the general public require seismic hazard estimates for land use planning, improved building design and construction (including adoption of building codes), emergency response preparedness plans, economic forecasts, housing and employment decisions, and many more types of risk mitigation. The basic elements of modern probabilistic seismic hazard assessment can be grouped into four main categories: Earthquake Catalogue, Earthquake Source Model, Strong Seismic Ground Motion, Seismic Hazard Assessment. Seismic hazard depicts the levels of chosen ground motions that likely will, or will not, be exceeded in specified exposure times. Hazard maps commonly specify a 10% chance of exceedance (90% chance of non-exceedance) of some ground motion parameter for an exposure time of 50 years, corresponding to a return period of 475 years. The published European-Mediterranean Seismic Hazard Map depicts Peak Ground Acceleration (PGA) with a 10% chance of exceedance in 50 years for a firm soil condition. PGA, a shortperiod ground motion parameter that is proportional to force, is the most commonly mapped ground motion parameter because current building codes that include seismic provisions specify the horizontal force a building should be able to withstand during an earthquake. Short-period ground motions affect structures with corresponding short-period resonance vibrations (e.g. oneto-three story buildings, the largest class of structures in the world). The map colours chosen to delineate the hazard roughly correspond to the actual level of the hazard; the cooler colours represent lower hazard while the warmer colours represent higher

hazard. Specifically, white to green correspond to low hazard (08% g, where g equals the acceleration of gravity), yellow and orange to moderate hazard (8-24% g); reds to high hazard (> 24% g). The unified ESC-SESAME seismic hazard model is the result of the combined efforts of multidisciplinary research groups on seismotectonics, earthquake catalogues, and hazard assessment during more than ten years within the framework of cooperation projects, programmes, and initiatives at international level. The map is one of the possible results that can be generated through the homogeneous procedure for seismic hazard assessment for the European Mediterranean region as developed within two main project frameworks: International Correlation Programme (UNESCO IGCP-382 SESAME Project) and the European Seismological Commission (ESC). This unified ESC-SESAME seismic hazard model allows as well to map different ground motions (peak ground acceleration, PGA, and spectral acceleration, SA) corresponding to portions of the bandwidth of energy radiated from an earthquake and for different return periods and soil conditions. PGA as depicted in the map and 0.2 SA correspond to short period energy that will have the greatest effects on short period structures (up to about seven storey buildings). Longer period SA maps (1.0 s, 2.0 s, etc.) would depict the level of shaking that will have the greatest effect on longer period structures (10+ story buildings, bridges, etc.). The unified ESC-SESAME model allows as well to generate maps for different return periods e.g. 72-year (50%/50 years) which is a non conservative estimate that is often used for the usable lifetime of a building or the 4275-year return period (2%/50 years) which is the recently established standard for building codes and which includes very rare large earthquakes. The 475 return period (10%/50 years) values as depicted in the map reflect a standard degree of conservatism which includes large rare earthquakes and it was employed almost universally for building codes in the last several decades. The ESC-SESAME seismic hazard model for Europe and the Mediterranean constitutes a regional seismic hazard framework for the region in terms of peak ground and spectral acceleration from which seismologists, geologists, earthquake engineers, and architects can profit as a general guideline. Nevertheless, it should be pointed out that the ground motion estimates in the EuropeanMediterranean seismic hazard map provide a reasonable and consistent overview of the seismic hazard at regional scale but

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they do not provide adequate details to serve as bases for design values or for local mitigation strategies and decisions. The map (http://wija.ija.csic.es/gt/earthquakes/) received the 2003 Award for Excellence in Cartography of the International Cartographic Association (ICA), in the Scientific Map Section of the International Map Exhibition at the 21st International Cartographic Conference, held in Durban, South Africa, 10-16 August 2003.

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The seismic behaviour of traditional constructions with masonry walls

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Pere Roca Fabregat Doctor of Civil Engineering Professor of the Department of Construction Engineering at the School of Civil Engineering of Barcelona (Technical University of Catalonia), Spain

Introduction

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Buildings with bearing walls constitute a very substantial part of architectural and cultural heritage. This not only includes buildings listed as architectural heritage; complexes of buildings in old or historical centres are likewise important for their contribution to the cultural identity of a population or urban setting. Even if these complexes are not explicitly characterized as architectural heritage, they enrich our cultural legacy and its capacity to contribute, like emblematic monuments, to generating an important secondary economy associated with cultural tourism. In addition, constructions built with bearing walls continue to be used and form an integral part of the housing economy. The implantation of criteria of sustainability (making rehabilitation preferable to new construction since it represents far lower consumption of non-renewable resources and produces less waste) has given way to an economic and social revalorization of these constructions. All Mediterranean countries are subject, to differing extents, to a degree of seismic danger. It is therefore necessary to analyse the capacity of masonry buildings to stand up to earthquake and, as applicable, envisage possible strategies to improve their seismic response. In the case of heritage buildings, the principles of architectural conservation prioritize forms of intervention that respect the morphology and strength of the structure. The possible restoration or rehabilitation of these buildings therefore has to consider forms of intervention which, as far as possible, reconcile improved behaviour with maintenance of the building’s characteristic material and structural features.

The seismic behaviour of buildings with masonry walls A building with a structure of bearing walls constitutes a complex system whose stability in the face of vertical and horizontal actions is the result of the collaboration of various construction elements (bearing walls, bracing walls and structural floors). These elements collaborate to redound to the overall stability, so the individual failure of one may well affect other elements, generating the collapse of part or all of the structure like a house of cards. The bearing walls are generally very slender or even (as in Barcelona’s Eixample) extremely so. In most cases, the walls are not selfsupporting and need the bracing action of shear walls and floor structures to stand up. The individual failure of one or more

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1. Possible failure mechanisms in masonry buildings characterized by a) collapse of the façade, b) collapse of a corner, c) diagonal cracking of parapets, d) cracking of vertical pillars, e) separation of the base of the walls (rocking motion) and f) separation or cracking at the point of union between buildings.

bearing walls, or the fall of floor structures, may, as an immediate consequence, lead to the destabilization and collapse of other bearing or bracing walls. The failure of one or more bearing walls leads to the fall of floor structures, which may in turn cause the destabilization of other walls previously supported by the floor structure. The resulting structural system is delicate and becomes vulnerable to extraordinary events such as fire, earthquake, hurricane or explosions. In the case of deficient maintenance or abandonment, the deterioration of the floor structures (due to rot, in the case of timber beams, or corrosion, in metal girders) can also cause their failure and, subsequently, the loss of bracing action on the bearing and bracing walls. In the face of the horizontal action of earth tremor and wind, the walls may respond by developing shearing stress in their plane, provided they remain suitably braced by shear walls and floor structures. Resistance remains high even after cracking and slipping along mortar bonds, thanks to their residual friction. In general, there is no anchorage or reinforcement to prevent the structural floor and walls separating or slipping; in practice, the only mechanism preventing slipping is the friction that occurs on the contact surface. Even when the system of walls subject to planar shearing is sufficient to resist earthquake, a deficient union between walls


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Tool 5 Understanding structural damages The seismic behaviour of traditional constructions with masonry walls

and floor structure can lead to premature collapse as a consequence of the destabilization of a wall perpendicular to the plane of action of the horizontal forces. The fall of this wall will lead to the collapse of the floor structures and, as a result, the destabilization of the walls parallel to the forces, thereby leading to complete collapse. A well braced union between perpendicular walls is vital in order to guarantee the stability of the walls subject to planar shearing stress during the earth tremor. However, this is a fragile union and may break easily due to thermal effects, settlement, or during the earth tremor. In some cases (as in many buildings in Barcelona’s Eixample), the perpendicular walls are built without effective bracing, simply being built against each other, which is not fully effective in the face of an earthquake. These considerations suggest that this type of building is a particularly delicate system that is vulnerable to seismic action. Here, it is important to note that the seismic regulations of many countries (in particular, the Spanish NCR02) introduce very restrictive conditions as regards the use of this structural typology in places that are vulnerable to seismic movement (for example, limiting the number of floors to four for basic seismic acceleration of 0.08 g and to just two for seismic acceleration equal to or higher than 0.12 g), in addition to calling for more demanding construction details that are not characteristic in traditional construction.

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The seismic performance of traditional constructions The above reasoning is based on a rational understanding of the relation between the structure’s components and their joint response. However, these arguments ignore the reality of the real performance and the effective resistant possibilities demonstrated by traditional constructions. The existence of a huge legacy in this structural type, even in markedly seismic countries such as Italy or Greece, logically suggests that even with the weak points identified in the above section, these buildings may present a satisfactory response in the event of earth tremors. One aspect to bear in mind is the adaptation that has taken place, in historical terms, between seismic demand and the capacity of local structural types to cope with it. Various parameters such as, in particular, the thickness of the walls, the height of buildings, the structural organization of the complex or the various construction details, have evolved to generate a response that is adapted to the seismicity of each geographical location. A detailed systematic study of the response of traditional masonry structures in Italy, especially after the earthquake affecting Umbria and Marche in 1997, has provided a rather more precise view of the real behaviour of these structures. This experience has shown that there is indeed a degree of adaptation between construction technology and local seismic demand, with the resulting capacity of traditional constructions to face up to earth tremors of average

2. Possible breaking mechanisms in buildings that share a party wall (D’Ayala and Speranza, 2002).

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3. (A) fundamental failure mode and (B) expectable mode in buildings with tied façades (Carocci, 2001).

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4. Estimated seismic damage scenario for a block in the historic centre of Palermo (Carocci, 2001).

Tool 5 Understanding structural damages The seismic behaviour of traditional constructions with masonry walls

or higher than average intensity without being destroyed. As observed in Italy, after various earthquakes, traditionally constructed buildings that suffered major damage or destruction had deficiencies such as defects of construction prior to the earth tremor, or were in a state of deterioration due to abandonment, or had been subjected to inappropriate transformations. The structures that survived the earthquake with very limited damage were well built and had maintained their traditional construction features. It might be concluded that a structure that is well built and maintained according to traditional techniques and procedures can stand up to earthquakes of average intensity. Nonetheless, in some cases traditional local construction may present seismic insufficiency or deficiencies. This particularly occurs in areas that do not have a consolidated memory of seismic activity, because earth tremors take place only very irregularly. Even in these cases, some seismic improvement can be made by introducing corrective measures which, though foreign to traditional local practice, can be applied by means of good practice in traditional or historical masonry construction. In places that are only moderately seismic, or where the most recent earth tremors took place at a remote time (and therefore have not produced a memory and an impact on construction techniques), buildings may present major limitations of resistance as a result of a traditional or historical construction technique which, despite its possible virtues, does not address the needs of lateral resistance. This might be said to be the case of many buildings in the Iberian Peninsula. In particular, various studies carried out in relation to buildings with bearing walls in Barcelona’s Eixample have shown that they are highly vulnerable constructions, even in the event of moderate earth tremors that are theoretically possible in Catalan territory (Barbat and Cardona, 2002, Bonett et al., 2003, Penna et al., 2004).

Resistance response and failure modes

5. Analysis using the computational model of the seismic response of a building with a party wall in the historic centre of Baixa Pombalina in Lisbon (Ramos and Lourenço, 2004). Estimation of maximum displacement.

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To cite Carocci (2001), we can recognise in traditional structures an implicit model that is the product of the experience in construction of a certain period of time and local culture. The traditional dwelling comprises a masonry structure organized in superposed cells to form units of several apartments. The structure is the result of the juxtaposition of simple construction elements; the building (house) can be regarded as an assembly of structures that are roughly superposed so that the walls constitute the masonry cell and the horizontal elements provide the floor structures and the roof. This form of juxtaposition produces a lack of robust connection between the parts, and the consequence of this defect is an overall fragility in the event of seismic action. The horizontal forces produced by seismic action push the walls that envelope the


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building outwards, orthogonal to their plane, and, above a certain value, cause them to reach breaking point (Giuffrè 1995). These constructions are, furthermore, characterized by their capacity to adapt to modification. This capacity is the result of the modular nature of the component materials: all of them can be dismantled piece by piece, even the walls. In the maintenance of these buildings, the repair or replacement of deteriorated stones or blocks is normal practice. This fundamental model may be subject to slight variations depending on the materials locally available, local cultural aspects or other factors. In urban construction, this model undergoes slight transformations to adapt to the complexity of the urban fabric or the morphological characteristics of the land. Even so, the construction systems tend to reproduce recurrent outlines and behaviours. The failure mode most frequently observed in the analysis of buildings affected by earth tremor in Italy is the collapse of the walls. This is the form that most markedly characterizes the vulnerability of this type of construction (figure 3a). This failure mode has been traditionally prevented by improving the connection of the façade to the rest of the structure by means of ties. In this case, the stability of the façade in response to earth tremors involves the walls perpendicular to it, which resist seismic action by working efficiently in their plane. When these walls can no longer resist the force, they develop diagonal fissures through which the system formed by the façade and the upper triangle of these walls separates from the rest of the structure (figure 3b). Unlike the first failure mode, which always leads to collapse, this second form does not necessarily mean complete failure, though it is normally accompanied by obvious damage. According to the material characteristics and layout of each building, and the characteristics of seismic action (direction of incidence), other forms of breakage are possible. By way of example, figure 1 presents various mechanisms observed in buildings affected by earthquakes in Italy (Binda et al., 1999, Binda et al., 2003). In historical centres, masonry buildings tend to form complex structural systems made up of various structurally connected buildings. In these conditions, the analysis of an isolated building cannot be sufficiently representative, since it is necessary to consider the system formed by the building in question and the adjacent constructions. This system allows us to envisage failure modes such as those illustrated in figure 2 (Carocci, 2001).

I. Knowledge

widely applied to analyse masonry (or reinforced concrete) structures is based on the hypothesis that floor structures constitute very rigid planes perfectly connected to their vertical counterparts (bearing walls or concrete screen walls). In masonry constructions, this hypothesis is only realistic when the floor structure comprises a concrete slab or, if it is built of timber or steel joists, it is topped by a sufficiently thick, reinforced layer of concrete that is connected to the vertical elements. In general, this is not applicable to traditional or historical masonry buildings, whose floor structures are not sufficiently rigid and deformable in the plane, as well as simply resting on the walls. A common approach in the past was to modify the structure of the building (introducing ties and top layers of reinforced concrete) in order to adapt the construction to the hypotheses of the calculation method. This represents a major transformation of the building and the inclusion of elements that are far more rigid than the walls, which can have counterproductive effects in the event of earth tremors. Once again, the observation of the effects of earth tremors to have occurred in Italy in recent times shows that this type of intervention may even increase the building’s vulnerability to earth movements, due to the danger of the floor structures pushing out the walls and rendering them more unstable. The visualization of failure modes actually observed suggests a different approach more in keeping with the nature of the construction and resistance of these buildings. The building can be analysed by the mathematical formulation of the possible mechanisms of damage using the limit analysis technique and applying theorems of plasticity. Given the experience available (at least in Italy), these methods can be gauged using a qualitative analysis based on the observation of the behaviour of a large number of buildings of similar characteristics (Binda et al., 1999, Binda et al. 2003). This method has been recently incorporated into the Italian OCPM seismic regulations (2005). The study of blocks formed by buildings or urban fabrics calls for a more general approach, due to the greater complexity of the problem. The observation of alterations or irregularities (such as empty spaces or changes of height) is essential in this case. In this context, action takes the form of studying damage scenarios for earthquakes of a given magnitude and considering the characteristics of the typical buildings and possible variations or alterations in the fabric. The analysis can be based on a qualitative approach (figure 4) or a detailed calculation based, for example, on modern techniques of computational calculation (figure 5).

Analysis techniques Improving seismic behaviour It is necessary to bear in mind that certain techniques conventionally used to calculate bearing wall structures may not be suitable in the case of historical or traditional buildings. In particular, the method of rigid planes, which is well known and

In practice, the complete adaptation of traditional structures to the standards of structural safety in the event of earth tremor required by regulations for new constructions of concrete and

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steel may lead to a transformation and a very substantial disfiguration of the original structure. In the case of traditional or historical constructions, this transformation may be incompatible with the conservation of the building’s historical and cultural values, and may produce a major loss in terms of cultural legacy. This particularly occurs when the original structure is reinforced by means of elements of concrete, steel or other materials not used by traditional or historical construction techniques. On many occasions, these reinforcements have been invasive and irreversible, causing irreparable damage and loss to the original construction. Furthermore, and as already suggested, the study of the seismic behaviour of previously reinforced buildings in Italy after the earthquakes in Umbria and Marche showed that reinforcements imposed on the original structure have a counterproductive effect due to the mixed nature of the resulting complex. In particular, it has been observed that the replacement of traditional floor structures by concrete floor slabs and wall ties in masonry walls can produce an inefficient form of reinforcement that may even hasten the building’s collapse during an earthquake. For all of these reasons, in recent decades there has been a major change of paradigm in ways of understanding the seismic improvement of traditional buildings. We currently understand that structural restoration is based on knowledge of local construction techniques and recognition of their possible deficiencies. Knowledge of local construction procedures is fundamental and must guide the choice of interventions. In view of the fact that traditional buildings in many seismic regions present a degree of adaptation to local seismic demand, it is generally preferable to base reinforcement on an analysis of the construction features that characterize these constructions and avoid conflicting solutions. Seismic improvement can take the

form of repairing deterioration and recovering original resistance, without having to implant reinforcements that have nothing to do with traditional construction technology. In some cases, an improvement in seismic resistance may be necessary due to the degree of deterioration of a building as a result of lack of maintenance or deficiencies in the construction process or materials. The need for reinforcement may also be due to the fact that local construction tradition simply overlooks the need for seismic resistance (as can be seen in various places in the Iberian Peninsula). Even in these cases, it is preferable to have recourse to solutions that are compatible with traditional or historical construction and that tend to preserve a degree of material and organizational homogeneity. It is preferable for interventions to control or mitigate possible weak points in a building rather than effecting a far-reaching alteration in its construction and resistance. Intervention can be designed in accordance with traditional or historical construction techniques in order to help limit the deformations experienced during an earthquake or avoid excessive separation between the parts. Anchoring façades or joining walls to floor structures or other walls using ties is a very efficient traditional solution for joining elements without producing substantial changes in their rigidity (figure 6). In general, interventions should aim to improve the quality of the masonry walls and their connections (between the walls and to the floor structures), reduce thrusts, stabilize vulnerable elements and reduce structural irregularities. The opportunity of increasing the rigidity of floor structures to enable them to work as rigid diaphragms should be considered judiciously, since it calls in all cases for a clear understanding of the possible effects on the building as a whole. Furthermore, the work must be carried out with great care.

Conclusions

6. Use of ties in a building in Bergamo, Italy.

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The study of the effects of earth tremors on traditional constructions with bearing walls, centring particularly on the case of the earthquake that affected Umbria and Marche in Italy shows that these buildings do to a degree combine construction techniques and local seismic demand, enabling them to survive earth tremors of average or average to high intensity without being destroyed. However, this capacity may be compromised if the building presents original defects of construction or materials, or a state of deterioration due to lack of maintenance. It is also necessary to recognise that in some geographical regions (particularly in the Iberian Peninsula), local construction culture does not address the need for seismic resistance, due to a lack of historical memory as regards the possibility of earth tremors. In these cases, improved


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I. La connaissance

seismic resistance may be needed. Even if the building presents deficiencies, it is essential to base improvements on a knowledge of traditional or historical construction procedures, as it is preferable for interventions to control or mitigate possible weak points than effect far-reaching alterations to the nature of the construction and its resistance, at the same time maintaining their homogeneity and constructional uniformity.

References NCSR-02. Norma de construcción sismorresistente: parte general y edificación.

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Ministerio de Fomento, Madrid, 2002. Barbat, A. H., Cardona, O. D. (2002), “Evaluación de la vulnerabilidad y del riesgo sísmico de edificios” in Evaluación y Rehabilitación Estructural de Edificios. CIMNE, Monograph no. 65, Barcelona, 325-340. Binda, L., Gambarotta, L. Lagomarsino, S., Modena, C. (1999), A multilevel approach to the damage assessment and the seismic improvement of masonry buildings in Italy. Seismic Damage to Masonry Buildings, Monselice, Padua, 179-194. Binda L., Anzani A., Baila A., Baronio G. (2003), “A Multi-level Approach for Damage Prevention in Seismic Areas. Application to Historic Centres of the Western Liguria”, Atti della 9NAMC (9th North American Masonry Conference), South California. Bonett, R., Penna, A., Lagomarsino, S., Barbat, A., Pujades, L., Moreno, R. (2003), “Evaluación de la vulnerabilidad sísmica de estructuras de mampostería no reforzada. Aplicación a un edificio de la zona de l’Eixample de Barcelona.” Revista Internacional de Ingeniería de Estructuras. Escuela Politécnica del Ejército, Ecuador, Vol. 8, no. 2, 91-120. Carocci, C. F. (2001), “Guidelines for the safety and preservation of historical centres in seismic areas”, Proceedings of the 3rd International Conference on Historical Structures, University of Minho, Guimaraes, 145-166. D’Ayala, D., Speranza, E. (2002), “An integrated procedure for the assessment of the seismic vulnerability of historic buildings”, 12th European Conference on Earthquake Engineering. Article no. 561, London. Giuffré, A. (1995), “Vulnerability of historical cities in seismic areas and conservation criteria”, Terremoti e civiltà abitabile. Annali di Geofísica, Bologna. ORD. PCP, no. 3431: Norme tecniche per il progetto, la valutazione e l’adeguamento sismico degli edifici. Consiglio dei Ministri, Rome. Penna, A., Cattari, S., Galasco A., Lagomarsino, S. (2004), “Seismic assessment of masonry structures by non-linear macro-element analysis”, Structural Analysis of Historical Constructions IV, Balkema, Leiden. Ramos, F., Lourenço, P. B. (2004), “Modelling and vulnerability of historical city centres in seismic areas: a case study in Lisbon”, in Engineering Structures 26, 1295–1310

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Identifying types of damp: the causes and the lesions they produce

I. Knowledge

Soledad García Morales Doctor of Architecture Technical University of Madrid, Spain

Introduction Traditional Mediterranean buildings are not impermeable or waterproof constructions. This basic affirmation serves as a frame of reference in which to study the problems that water produces when in contact with this type of buildings. In fact, foundations, walls and roofs have been designed and produced over the centuries so that their materials can absorb damp, which means that they can also evaporate it. The balance between the two flows (absorption and desorption), determined by climatic and microclimatic conditions, has constituted the success of a given typological construction solution.

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What are the types of damp to which a building and its elements are subjected? An initial classification divides the types according to the source of the water: from the ground, rain or use. This division can be further nuanced if the form of penetration is introduced: with or without pressure, intermittent or constant, etc. As we will see, this nuance is interesting because the criteria of intervention will be clearly guided by the answers to these questions.

Ground strata (1. Phreatic; 2. Capillary; a. Absorption; b. Damp ground; c. Underground water; d. Impermeable ground)

1. Damp from the ground

2. Water content in soil

The most frequent types of ground damp are:

The mathematical means of expressing the amount of water in soil is its volumetric water content, representing the amount of water per unit of dry bulk soil:

Water from an aquifer Water from the capillary fringe Rainwater absorbed by the ground Runoff water that may filter through the paving, giving rise to “false” damp. False water or “perched” tables In order to provide a complete definition of the possible pathological states caused by these forms of damp it is first necessary to define the states of stress—that is, the factors considered to be water “loads” on the site. The most frequent are: The amount of water contained by the soil The pressure exerted by the water.

w = Mw / Ms (%) Ce contenu est défini en mesurant la perte d’eau que subit le sol This is defined by measuring the water loss undergone by soil that is dried for 24 hours in a kiln at 105-110ºC (BS 1377). These values usually oscillate at around 5% for gravel and sand, and 50% for fine-grained cohesive soils (clays). Another way of estimating the degree of moisture is the degree of saturation Sr: the percentage of voids in the soil full of water, as opposed to the total porous volume. The degree of saturation is not a term for comparing soils, but it does enable us to relate the moisture content with the form of penetration, because the degree of saturation increases with the greater pressure with which water is introduced into the ground. We will use both expressions to describe the states of stress.

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3. The pressure of water in the ground The pressure of water in the ground is expressed by the term “pore pressure “ n, which is defined as an excess of pressure in the pore, greater than atmospheric pressure.

4. Stress caused by groundwater level

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Soil below the groundwater level is saturated (saturated zone): its degree of saturation Sr is 100%. Water in this stratum is under pressure, and, in the event of coming into contact with an underground construction element, with give rise to intense stress in which the appearance of lesions may be produced by water dripping or gushing onto the wall facing. The strata in contact with the groundwater level become damp due to capillary action (wet strata). The degree of saturation here is close to 100% at the limit with the groundwater level, and decreases with distance. The gradient depends on many factors (porosity, surface tension, etc.). Some land has a low capillary level, with a shallow wet area (earth with a coarse grain and voids larger than 0.5 mm), whereas others, with finer pores, contain water to a depth of several metres. The depth of this area of partial saturation (capillary fringe) constitutes the capillary level and can only be measured approximately by means of empirical formulas according to permeability K. Above the capillary level there is a further layer of damp earth containing not liquid water but water vapour that is diffused into the atmosphere (evaporation zone). The damp gradient continues, establishing decreasing degrees of saturation as it nears the surface. There may also be discontinuous damp in the form of traces of water at points of contact. As regards the pressure of water in this type of stress, pressure is said to exist when the earth is saturated—that is, below groundwater level. Above groundwater level, the capillary fringe becomes damp by suction (negative pressure) due to the surface attraction between the soil and the water (interfacial tension). The groundwater level as stress involves a presence of water under pressure acting on a large area of the foundations or on the underground parts of a building. As stress, it is not localized in extension or occasional in duration. It does not appear only when it rains, though a longer period of precipitation has the effect of an increase in hydrologic flow. Damp produced by the groundwater level generally appears at the moment of excavation, when the saturated zone is reached and water starts to gush over the surface, overflowing ditches. This type of lesion is frequent in buildings near watercourses or built on

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a surface aquifer. Functional or symbolical needs sometimes imposed construction in these places, and damp was accepted as a permanent factor. A frequent response was to construct systems to channel and drain these flows in order to reduce damage to a minimum. Many years of tradition often managed to tame the water using inventions that were masterly in their simplicity and wisdom: galleries, wells, gutters, cisterns, dams, etc., which are just some of the exponents of centuries of a culture of water. Our forebears were well aware that flowing water does little damage. These systems only ceased to work when blockages, diversions or breakage put paid to the original solutions. When this happens, the proximity of groundwater level to the underground walls of foundations or basements can take various forms: I. Pure phreatic stress II. Pure capillarity stress III. Stress caused by ground that is just “damp” I. Pure phreatic stress This is the result of burying the wall or foundations as far down as groundwater level. Since the flow is permanent and water

Conduits to channel water at groundwater level in a Spanish chapel


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pressure is high, this is the most serious problem. The buried wall and/or footing, as applicable, contain the following delimited areas (distinguished by their water content): Areas of localized penetration of water under pressure: joints, fissures, empty spaces, etc. are the weak points as regards the passage of the water under pressure. Penetration therefore starts here. Areas of saturated material: around the points of penetration, and in areas closest to the water, material is saturated. Areas of wet material: around the above. Areas of damp material: surrounding the wet areas. Rather than the characteristic stain, areas that are just damp sometimes only manifest a slight darkening, not always immediately visible. The gradient of water content produced by the groundwater level is permanent, not coinciding with drainage, nearby rain, pipe damage, etc. The only variations are seasonal, producing oscillations in the height of the water level.

retained by capillarity, without pressure. Penetration takes place due to mechanisms of capillarity from the ground to the wall. The decrease in free surface energy in the system generated when water leaves the ground and spreads through the pores of the foundation materials is the mechanism that triggers the very usual phenomenon of a damp basement or ground floor walls, even when there is no adjacent trapped water or saturated ground.

II. Pure capillarity stress In this case, the foundations or the wall are built not in the saturated zone, subject to pressure, but in the stratum immediately above, which, as described, only contains water

This form of stress is called pure capillarity� because the water that penetrates has no positive pressure: the mechanism is one of suction. In order to stop penetration, it is merely necessary to prevent contact between the ground and the facing, creating a

Stress caused by the capillary fringe in ashlar foundations (1. Wet area; 2. Damp area)

The height reached by rising damp depends on various factors: (Pve. Exterior evaporation (+ convection); Pvi. Interior evaporation (increase in relative humidity); 1. Surface capillary zone; 2. Direction of flow; 3. Waterproofed area?; 4. The water rises above the building’s base)

This type of stress produces a damp gradient in foundations or basement walls, footing, etc., characterized by lower water content than in the case of water under pressure. The materials in contact with the ground do not become saturated, so the resulting distribution is less extensive and intense. Even if the wall were sufficiently thick, the damp stain would not appear on the visible face. This means that water moves due to capillarity and turns into vapour inside the wall, and then continues its way due to vapour diffusion.

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ventilation cavity in which water can evaporate and be eliminated before reaching the building. The areas that will appear in the wall are: Wet area Damp area The conditions will be the same as in the above cases. The height reached by rising damp depends on various factors. In theory, the stain “stops” when the amount of water absorbed by the foundations is equal to the amount of water evaporated by the wall. As a result, the greater the wall’s capacity for evaporation, the lower the level reached. As the speed of evaporation depends on the ambient relative humidity, temperature, porosity and permeability of the materials, etc., it is these parameters that define the stress. If the rate of evaporation is high, water will not reach high levels. The lower the ambient relative humidity on the outside, the smaller the extent of the wet and the evaporation areas, supposing the permeability of the material is constant. Conversely, if a wall base is waterproofed using cladding that prevents evaporation, water tends to rise above the waterproofed area, seeking a new evaporation surface in order to return to equilibrium. In a well-ventilated traditional wall, the stain will normally be no larger than 30 or 40 cm. If it is higher, there is usually an additional problem (normally hygroscopic contamination of materials) masking capillary rise. The parts of the building affected by rising damp will be not only in the envelope (exterior wall); any element with foundations that reach the capillary fringe will present associated lesions. Water does not rise uniformly throughout the section of the wall.

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Capillary rise

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For example, in the case of a masonry wall with mortar, suction will occur more easily through the mortar than through the masonry, or even through the surface of contact between the stones and the mortar, if they are poorly bonded. The lines or surfaces along which water ascends most easily are those without mortar. It is therefore frequent to find different heights of damp in the vertical joints created between different non-interlocking fabrics, for example, between masonry walls and ashlar abutments if it is not a masonry arch III. Stress caused by ground that is just damp Having explained how water from the groundwater level rises by means of capillarity to a higher stratum (capillary level) and is then dispersed in the form of vapour through dry strata, seeking the open air (evaporation process), I will now describe how the presence of damp ground or other sources of water vapour may affect the walls. This is a frequent case, since all ground has a degree of damp, due to: The water that evaporates from a wet stratum towards the atmosphere Percolated rainwater, which, when precipitation ceases, starts to evaporate The remaining water in the ground, produced by leaks, irrigations, etc.

I. Knowledge

caves, crypts, etc., are cool, damp places even if they do not present damp patches. The damp contents are lower than in the other cases, presenting just one area: Area of damp material This area may not present the appearance of damp, just the deterioration of materials or claddings.

5. Stresses due to rainwater directly absorbed by the ground The various forms of stress in this section can be divided into two groups: Stress caused by rainwater absorbed into permeable ground Stress caused by perched water tables.

Water originally retained in the ground by capillarity can move through it if there is a difference in vapour pressure between the ground and the air: water spreads in the form of vapour (the ground evaporates). A wall or footing buried in the damp stratum become at least evaporators of this damp. It is well known that

IV. Rainwater absorbed by the ground When the ground is permeable to rainwater, the upper strata absorbs it and it seeps downwards (percolated water), according to the degree of permeability. In its course, water wets the ground, defining a gradient as it moves. Part of the water is retained in the ground by capillarity, and part percolates towards lower impermeable strata. In strata that are highly permeable, water is soaked up quickly. In clayey ground, filtration is slow and water covers large distances horizontally, due to the difficulty of penetrating into the ground. For this reason, contact with the buried wall or foundations is greater in the case of impermeable ground.

Stress caused by ground that is just damp (1. Damp ground; 2. Evaporation; 3. Damp materials)

Rainwater absorbed by the ground (1. Rain; 2. Damp area; 3. Wet area; 4. Damp area)

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The water content of ground in its different layers is, then, variable, provided exchange with the atmosphere (rain and evaporation) is not prevented by paving. This form of stress may be likened to pure capillarity, as it produces the same areas in the wall: Wet area Damp area

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The difference is that here, it is a phenomenon that coincides with precipitation, generally fast to appear and gradually disappearing with the evaporation of the ground. Further, stains are concentrated more intensely, coinciding with the ground level of the paving or the zone where the water is retained. V. Perched water tables Sometimes the composition of strata in the ground does not allow directly precipitated water to reach groundwater level. Water penetrates an initial permeable stratum, reaches an impermeable layer beneath and runs over its surface, constituting lines of flow or troughs that are above the groundwater level. These are called perched water tables, rapidly-forming flows that follow lines of least resistance in the ground (cracks in rocky ground, fracture lines, sandy areas of clayey ground, cavities or drains, infill, etc.), without constituting a saturated stratum. Following these lines, large volumes of water can travel a long way in a short time, producing localized stresses of water with variable flows and pressures according to the type of precipitation causing them. A stratum with perched water tables has variable water contents: larger at the runoff line, less in more remote areas. It can produce pockets with strong pressure, constituting a dangerous type of stress, sometimes confused with the groundwater level.

Rainwater absorbed by the ground. The deterioration of mural painting has started at the top, on the line coinciding with the ground on the other side of the wall

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A dangerous type of ground in this sense is one that has areas from which the fines have been washed out, making them very permeable strata that act as natural drains in more impermeable ground. The phenomenon is known as internal erosion or piping, and is dangerous because these lines of main flow can conduct large flows and pressures, washing out areas of ground and subsequently generating settlement in buildings constructed on them. Pockets of water form in depressions in rather impermeable ground. These pockets fill with rainwater and, depending on the flow received, can attain high levels of hydrostatic load that are difficult to evacuate. If one of these underground pockets breaks, it can generate penetrations of major flows and pressures. It is also relatively frequent in areas of historical construction to find underground rainwater cisterns and remains of obsolete, semi-obstructed gutters. All of these elements are potentially capable of acting as water pockets in the ground, in the event of being reached by some kind of subterranean stream. In more recent construction, the weak point for pocketing tends to be trenches built around foundations and filled in once work is complete. As the in-filling is not usually as compact as the natural ground, and since the water’s natural movement is interrupted by the presence of basement walls, screens, etc., the trench is potentially a pocket for runoff around the building. If to this we add the aggravating circumstance that this perimetric gutter is sometimes used, in small and freestanding buildings, to drain water collected by the roof and, on occasion, to water flowerbeds, the result can be very negative. However perched water tables form, the areas they potentially produce in the buried wall are:

A perched water table.


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Area of localized penetration with pressure A saturated zone, near the point where the water exerts the greatest load A wet area A damp area This could be confused with groundwater stress. The difference lies in the fact that this case involves phenomena of time, coinciding with rain, damage to cisterns during building work, lack of adequate drainage and waterproofing in basements where phreatic water was not apparent at the time of construction, etc.

6. The particular case of paved ground If the ground’s exchange capacity with the atmosphere is limited by paving, the damp content will be modified. The groundwater level does not receive the input of nearby rain, so its flow is fed by water precipitated at a distance. It is therefore logical to suppose seasonal variations. Saturation of the capillary fringe and the evaporation zone increases because evaporation is limited; the degree of vapour

I. Knowledge

saturation in the ground’s pores is greater, and upper layers generally increase in dampness, becoming fairly stable. If there are leaks or localized penetrations of water, the difficulty of evaporation produces retention of the water absorbed. Any defect in drainage, mains or sewerage leak becomes a problem of damp unless the ground drains easily. Paved ground can be considered a possible extreme case of a perched water table, with surface flow. If surface drainage is not correctly addressed, paving could have a negative effect, transporting all runoff water to the building’s foot or forming puddles, which penetrate faster than moving water. For these reasons, paved ground (streets, squares, etc.) around impermeable buildings is considered a risk factor on two counts: On the surface, because rainwater flows like perched water tables Under ground, since the difficulty of evaporation of any leak or penetration will prolong water retention and increase the degree of saturation of the ground. This is a relatively frequent case in villages whose streets have been paved recently. Paving interrupts the equilibrium established between the buildings and their surroundings (according to which both collaborated in the absorption and evaporation of rainwater), giving rise to damp patches at the bases of buildings that were not designed to resist the stress of large runoff.

7. Damp caused by hygroscopic condensation

Paved ground (1. Impermeable paving; 2. Rainwater is conveyed to the base of the buildings; 3. Impermeable paving; 4. Elevation of evaporation area; 5. Penetration through exterior paving)

This is an alteration of materials that modifies their behaviour with regard to water (liquid or vapour), aggravating lesions caused by damp and hindering their diagnosis. It is caused by the contamination of materials by hygroscopic salts, water-soluble chemical substances that are quick to absorb water, with which they combine to form hydrated salts. These salts dissolve in water from the ground, seepage, etc., and penetrate into buildings. When the wall evaporates, the salts are retained in the porous makeup of the materials and crystallize there as they lose water. If they lose all their water, they form a whitish power, or a crust or spongy growth, known as efflorescence. When the ambient conditions of relative humidity rise above a certain value (variable for each type of salt), the deposit starts to adsorb1 vapour and the salt is hydrated. When hydrated, some salts dissolve completely, and then the construction element presents the appearance of being wet or even saturated, giving the impression that liquid water is producing this stain, when in fact it is only due to the humidity in the air acting on abnormally hygroscopic materials. In this case,

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we speak of damp caused by hygroscopic condensation. Normally, a building that presents this type of lesion has undergone real damp of some kind (capillarity, rain, flooding, etc.), which provided the vehicle conveying the salts to the wall. But this real damp may have disappeared, and the wall retains only the deposited salts, which are reactivated not by the presence of water in the ground, but by the increase in damp in the atmosphere. The stain reappears in its original form, but is deceptive. This is the cause of much of the damp in old or historical buildings. It is a type of patch that will not away, resisting all traditional removal attempts. Since the cause is the contamination of the materials, until the hygroscopic salts are eliminated it will not disappear.

Tool 6 Understanding the processes of degradation of the materials used Identifying types of damp: the causes and the lesions they produce

They are aggressive because when they crystallize they exert pressure on the pores that may cause materials to deteriorate, though they are in general less hygroscopic than nitrates and chlorides. Disappearance of the stain when the render is chipped away or the contaminated materials eliminated is a characteristic symptom that damp is caused by hygroscopic condensation. (Figures show how the damp stain disappears from the area of the mortar bonding being removed, because in this case the hygroscopic salts are near the surface, and the mortar beneath looks dry and sound. In this wall, the salts also affect the brick, which should be replaced by new materials, not always an appropriate course of action, as decided on this site.)

The salts may have different sources: 8. Damp caused by other sources of vapour Nitrates: from organic matter, such as cemeteries, stables, organic waste dumps, etc.; buildings that have been used to store foodstuffs or stable animals, etc. Chlorides: traditionally associated with seaside places, they may also be found in buildings that have been used to conserve foodstuffs using salt. In some climates where snow or ice in the streets is eliminated using salt (sodium chloride) the outside walls tend to be contaminated. Finally, some chlorides are organic in origin. Carbonates: associated with the dissolution of construction materials or minerals in the ground. They do not tend to be hygroscopic like the above. Sulphates: from the ground or other construction materials.

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A mass of theoretically dry, underground air (cave, crypt, etc.) will attract the water vapour in the ground surrounding it. If the pressure of the vapour is high, the pocket of air may reach high values of vapour saturation (high relative humidity). If, furthermore, there is some point of penetration of liquid water, the cave or crypt will be 100% saturated if the conditions are maintained for a sufficient length of time. In the Mediterranean tradition, caves and crypts are ventilated, and our ancestors proved to be as knowledgeable about the dissipation of vapour by convection as about the drainage and conduction of liquid water. If these spaces, which were traditionally ventilated, are subdivided

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Tool 6 Understanding the processes of degradation of the materials used Identifying types of damp: the causes and the lesions they produce

A mass of theoretically dry, underground air (cave, crypt, etc.) will attract the water vapour in the ground surrounding it.

I. Knowledge

Normally, the facings are designed so that the amount of water absorbed can evaporate in the interval between precipitations. In this way, even if the wall gets wet, provided it has time to evaporate no major lesions are produced. The amount of water absorbed even serves to cool the walls and roofs when it evaporates, as explained above. The only precaution is that the wall has to be thick enough to prevent the damp front from reaching the inner facing. Pathological situations start to occur when the bonding agents deteriorate, not only absorbing water into the pores but also allowing it to run along the joints between the materials, forming a runoff surface that may be interior. In each architectural typology, it is important to ensure that the relation between runoff water/water absorbed is optimum for a given climate. The different construction solutions represent practical experience of permeability and capacity for evaporation of the available materials, and the quantities and thicknesses of bonding and rendering mortars.

10. Diagnosis due to changes in use or given windows that are too airtight, condensation pathologies appear. Condensation is manifested by the growth of biological colonies (bacteria and fungi) on facings and on the coldest or least ventilated points of the wall, like the corner. For this to occur, the relative humidity of the air beside this facing must be 80%.

9. Damp caused by rainwater seepage In the Mediterranean, where the climate is usually dry, traditional buildings are not especially protected from rainwater. Normally, the materials are porous and permeable, even in some roof solutions, which are designed so that low-level absorption of water into their mass contributes to cooling the air inside, thereby improving comfort levels. Rainwater mainly enters buildings by means of one of two mechanisms: A mechanism of absorption and suction through the pores of the materials Seepage through joints. When rain falls on a flat roof or against a wall, part of the water is absorbed by the materials and joints, and part runs off the surfaces. The amount of water that drains off the building is in inverse proportion to the amount that is absorbed by it.

Now we are familiar with the different types of damp that occur in traditional architecture, we can go on to establish a methodology for inspection, diagnosis and intervention. Inspection Relevant symptoms are those that serve to classify the type of lesion observed. The most important symptoms are damp patches, with attention to and analysis of the following factors: Position Size and shape of the stains How they appear Coincidence in space or time Other symptoms may also be significant (colour, smell, efflorescence, deterioration of materials, etc.). In addition to inspection, the following information about the building is also relevant: Historical data Graphic and photographic documentation, if it exists Information about interventions or modifications: building work, repairs, changes of use, etc. Information about the environment: gradient, composition and permeability of the ground. Information about nearby urban networks (past and present).

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Tool 6 Understanding the processes of degradation of the materials used Identifying types of damp: the causes and the lesions they produce

All of this information, as explained above, serves to produce an initial hypothesis as to the cause of the damp. To corroborate whether this initial hypothesis is correct or complete, we have various instrumental techniques to support diagnosis. The simplest and cheapest is data collection using a thermo-hygrometer. This instrument measures air temperature and humidity, allowing us to locate focuses of evaporation in walls, footing or roofs. It is interesting to conduct the inspection with the aid of this apparatus, since stains do not always correspond to true focuses of evaporation; in some cases, it is hygroscopic condensation, in which case the materials condense rather than evaporate water, which can be detected fairly easily using this technique. The results of the study can be represented on plans. Rainwater absorbed by the wall

Complementary studies After analysing the readings of the thermo-hygrometer, it may be necessary to use another technique to check and locate the focuses. In this case, the study required will depend on the hypothesis or preliminary diagnosis:

The water absorbed can evaporate in the interval between precipitations

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A geotechnical study is useful for locating a focus of ground damp when we suspect the presence of the groundwater level or a capillary fringe. Exploration of the building’s hygrothermal behaviour in greater detail (ventilation, risk of condensation, drying rate in correlation with the climate, etc.) requires a complete hygrothermal study, with the installation of a thermohygrometer to constantly record information (data logger) programmed with a data collection protocol in keeping with the type of study desired. Drilling tests with archaeological supervision serve to locate specific focuses.

Map of damp focuses detected in the church of San Salvador, in Toro (province of Zamora, Spain)


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If you suspect that damp is due to damage to the sewerage system or the presence of mains, they should be inspected using appropriate techniques (inspection using TV cameras; detection of sinks; detection of leaks in the water-supply network, etc.) To detect the role of the hygroscopic salts present in the materials and their possible influence on the behaviour of materials in relation to water, laboratory tests are needed. This involves taking samples of the materials in question. There are many possible tests, too numerous to go into here. Finally, if the damp problem seems to be due to rainwater seepage, on-site tests can be carried out to simulate it, using a spray, water jet, or puddles of water on the element in question.

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In any case, these studies are only useful on the basis of a prior hypothesis. They serve as verification in response to questions tabled by the expert or researcher. Technique alone is not enough to substitute the processes of inspection and study.

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Adsorption is the mechanism by which gases adhere to the walls of pores or the surface of the materials. In this case, the gas adsorbed is water vapour.

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Tool 6 Understanding the processes of degradation of the materials used

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Degradation of Building Materials (stone, earth, timber)

Maria Philokyprou Architect and Ph.D. in Archaeology Town Planning Officer, in the Section of Building Conservation in the Department of Town Planning and Housing, Cyprus

I. Introduction Building materials of Cyprus

Formation, which is the second in preference material used as ashlar, is a yellowish, porous material with biogenic constituents and few igneous ones loosely adhering together. The choice of stone used was usually a function of the geology of the immediate environment of the settlements.

Introduction Stone, earth and timber, always available in nature and in the vicinity of the various settlements, have been the basic building materials for the construction of traditional buildings of the 19th and 20th century. 6

Stone Stone, either as rubble or in dressed form (called ashlar) has always been the most common material used for the construction of walls and, to a lesser degree, floors. For rubble walls, the stones used were those available in the vicinity of the settlements and were usually sedimentary rocks (calcareous sandstone, limestone) as well as igneous rocks (diabase, gabbros). In the villages of the plains where stones were rather scarce, their use was usually limited to the construction of the foundations and to the lower part of the walls. The stone wall height differs from area to area. The ashlars, mainly used, were sedimentary rocks of various formations (usually calcareous sandstone of Pachna, Athalassa – Nicosia as well as Koronia Formation and chalk of Lefkara Formation). The calcareous sandstone of Pachna formation was the main source of ashlar and was suitable for building purposes. It is a hard stone and constitutes small to medium particles. Its main components are biogenic (algae, protozoa, bivalves, foraminifera), some silicates (quartz, feldspars) and sometimes fragments of igneous rocks, all well bound together with microcrystalline calcite, micrite or sparite. The calcareous sandstone of Athalassa – Nicosia

Ashlar stone. Calcareous sandstone of Nicosia and Pachna

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Mudbrick In traditional architecture, extensive use of mudbricks was made, especially for the upper part of the walls. For mudbirck manufacture, locally available calcareous soils with relatively high clay content were used. The clay soil was mixed with the necessary amount of water and puddled thoroughly so as to produce a mixture plastic enough to be handled. When it was uniformly wet, plant material such as straw, reeds and seaweed were added and left a few days to ferment, thus releasing natural vegetable glue that gave the final product consistency, flexibility and elasticity. Plasters and mortars In traditional architecture, plasters of gypsum as well as of clay composition were employed. The use of lime was relatively limited. For mortar, mud was mainly used. Mud requires simple technology compared with other plasters, as it can readily be prepared from clay soil with the addition of water. The mud owes its adhesion properties to the clay minerals present in the soil. Very often in wall mud mortar and plaster, tempering additives such as straw were employed to prevent cracking through increased coherence. A special category of plasters is that of the hydraulic ones. These were mainly used in structures requiring hydraulic properties (water mills etc).

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Outil 6 Understanding the processes of degradation of the materials used Degradation of Building Materials (stone, earth, timber)

Timber The use of timber, especially pine and cypress was limited mainly to the construction of roofs, storey floors, doors, windows and auxiliary walls. II. Degradation of stone The main problems encountered in the stone wall constructions are due to the degradation of the building material or the construction as a whole. The degradation is mainly due to the decomposition of the stone itself, the damages at the corners and often on the whole extent of its visible surface and the alteration in its compact appearance. Sometimes stone cracks appear in places where metal elements are used for fastening timber frames when such metal parts are corroded. In some cases stone cracks may be due to the overloading of the upper part of the stone lintel of windows and doors. Other problems encountered in stone construction are declination of a wall, its separation from the rest of the construction and its total collapse. Sometimes walls perpendicular to each other tend to separate and also the two faces of a wall may also separate. Finally, in stone constructions, cracks, degradation and falling off of plasters and mortars may lead to the loosening and falling off of the building stones. The main causes of degradation 1 (decomposition, erosion, cracking) of stone material itself are: a. Rising damp as well as dampness from the rain or other causes. Dampness usually appears in the lower part of the wall and to a lesser degree to higher parts (even in the highest parts of the wall). The presence of water and dampness may affect to the clay constituents of a stone and also lead to salt crystallization. b. Chemical causes and influence of biological factors and atmospheric pollution may cause alteration of the constituent elements of the stone.

Degradation of stone

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c. Mechanical causes (loading and stresses) which leads to the excess of the maximum strength of the stone elements. It must be emphasize that in the Cyprus Traditional Architecture the presence of dampness in the stone wall constitutes the main cause of most of the physical and chemical changes in the structure of the stone elements (mainly in the sedimentary stones which are the most porous materials and especially in buildings near the seaside). Water can enter the stone with the condensation of vapour in the air and the penetration of the rain water if the material is porous2, as well as with the process of capillarity (movement of water from the ground upwards and evaporation when it comes to a free surface). Capillary Rising Water either in liquid form or vapour can enter all porous materials. The pores which have very small diameter act as capillary tubes and create absorption of the water. This happens because there are forces of cohesion in the tubes between the water and the tube walls which are greater than the forces between the water particles themselves. Thus the water tends to spread to a greater surface within the tube and seeps through its tube wall overcoming the force of gravity. The water creates erosion in the stone elements directly with the washing of its soluble constituents (degradation of clay particles) and indirectly with the transfer of the soluble salts and their crystallization. a. Degradation of stone due to the presence of water and dampness Action of water on the clay constituents Most clays expand when absorbing water and change into fine powder when they dry. The clay deteriorates because of its expansion with the absorption of water. With the increase of the volume of the constituent elements of clay composition

Degradation of stone and mudbrick

Degradation of stone

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mechanical forces are developed with the result that the stone containing such elements is substantially deorganized. Salt crystallization Salt crystallization constitutes one of the most important causes of erosion and degradation of stones and acts on all types of stone irrespective of their chemical composition. Main sources of the salts are the ground surface, the subsurface, the sea, the atmospheric pollution of the rain water (since it increases the ground pollution) and the use of wrong building materials in contact with the stone (cement plasters and mortars). The main soluble salts are the chlorides, sulphides and sulphates3. The salts enter the pores of the stone (or smaller cracks) during the absorption or capillary rising of the water which contains salts. The water is absorbed directly from the rainfall or rises from the ground by capillary action. The capillary action is due mainly to the longitudinal pores, perpendicular and through, with small diameter. When the water is saturated (because of the fall in temperature or evaporation) the soluble salts crystallize either within the stone pores or on its surface where efflorescence is created. Sometimes the salt crystallization may take place both on the surface and in the pores of the stone. When the salts crystallize, their volume is increased4, the pores are partly filled and great stress is created on the wall (of the pores) and the pores themselves with destructive consequences. This leads to the degradation of the building stones. Crystallization can create mechanical tensions thinning of the stone surface and separation of small parts from it, breaking up of the building material. The above concentration of salts on the stone surfaces due to the continuous movement of water towards the external surfaces of the materials has as a result, apart from the deterioration of the stone elements, the deterioration of the plasters and mortars (development of surface tensions, minor cracks, separation of plasters from the stone and gradual destruction). The degree of the above phenomenon depends on the percentage of water content in the pores and the permeability

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of the stone. The phenomenon of degradation – erosion due to salt crystallization becomes much more drastic in the coastal regions of the island i.e. Larnaca. b. Degradation of the stone due to biological factors and atmospheric pollution. Biological factors The erosion due to biological factors include the chemical changes which are created by microorganisms (algae, fungi etc) as well as those due to insects, birds and the growth of roots or plants which penetrate the joints or cracks, exerting mechanical stresses. Dampness also leads to the development of microorganisms which create deterioration. Atmospheric pollution (sulpher and carbon oxides) The degradation of stone due to atmospheric pollution is not as intense in Cyprus as are the factors mentioned above, because of the rather low atmospheric pollution of the island. The pollutants which create the deterioration of the stone elements are usually carbon dioxide and sulphur oxides. As already noted the sulphuric acid reacts quickly with the calcium carbonate of the calcareous stones and dissolves it when the stone elements are exposed to rain water. The atmospheric carbon dioxide which has dissolved in rain water gradually dissolves the calcite creating soluble constituents and when the solution dries, calcite or aragonite is recreated. The atmospheric dioxide acts only on calcareous stones which are exposed to rain water and the result is a very small reduction of their dimensions. c. Degradation of stone due to mechanical stresses Problems of stone due to the mechanical stresses caused by expansion and contraction of the material are not intense in Cyprus due to the rather limited fluctuation in temperature. Sinking of the foundations, earthquakes and the wrong practices in building (without interconnecting of the two faces

Structural problems of stone walls

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of a wall) may cause problems not only in the construction but also to the stone itself (cracking etc.)

III. Degradation of mudbrick ?he main damage of mudbricks is the degradation, disintegration and the deterioration of the material itself. This is very obvious at the base of a wall and to a lesser degree at the top or other parts of the wall. Some other problems of the mudbrick walls are the mechanical ones such as cracking, the inclination (vertical or horizontal), bulges and slumps, horizontal movements and bending of the walls. These can affect also the material itself. The above mentioned damages depend on the quality of the mudbricks as well as the structure of the wall. The quality of the mudbricks depends on the quality of soil used for their production, the organic additive and generally the procedure in their preparation (time left for the fermentation of soil, the mixing of the ingredients together, the drying period etc) and also the geo-technical characteristics of the final product. The quality of the mudbricks depends also on the experience and training of the workmanship used. Damages on a mudbrick wall may be caused due to the structural system of the wall (insufficient connection between the two parts of a wall, incorrect laying of the mudbricks in alternating rows) and also due to the climate conditions of the area (presence of water and dampness). The main causes of degradation of mudbricks are a. Water and dampness (leading to the disorganization of clay elements and the creation of salts). b. Biological factors c. Mechanical stresses a. Water and dampness Water and dampness (rising damp from the ground, rain water, bad workmanship and other problems in the structure

Detachment and cracks of plaster

I. Knowledge

constitute the main causes of deterioration of the constituent material and the organic additives. Disintegration of the material of mudbick is the process when the soil forming the mudbrick loses cohesion due to the existence of water and moisture. The dampness and water fill the pores of the mudbrick and the soil particles lose cohesion /connection between them and the mudbrick material is pulverized5. Additionally due to the presence of water the straw used in the mudbicks rots, swells, dries and is pulverized. The process leading to this damage is the penetration of water into the material. The dampness that enters the wall causes evaporation or creation of salt crystals. The creation of these crystals causes loss of the cohesion forces, disintegrates the material and increases the size of the pores, leading the mudbrick to pulverization. The dampness also causes serious problems to the plaster and also the mortar of a mudbrick wall. The dampness may enter the pores of the surface between the plaster and the wall. It penetrates directly into the connecting surface or comes to the surface through the mass of a wall. Dampness located in the area between plaster and mudbrick causes evaporation /condensation depending on the temperature and humidity conditions of the surroundings. Dampness also brings soluble salts near the surface. When the humidity dries, salt residuals are formed. The creation of salts increases the size of pores (swelling) creating additional pressure in the pores that causes loss of the cohesion / connection forces and internal cracking develops. The plaster is detached and collapses. After the collapse of the plaster the mudbricks themselves remain exposed to humidity and water with the result that deterioration and decomposition is speeded up. In addition, when a mudbrick wall looses its external plaster and is left exposed, water may cause extra problems. Running water forms small vertical channels on the wall increasing the surface area exposed to damaging conditions. The damages caused by water and moisture can be observed more frequently at the base of a wall, when the stone base is very

Deterioration of mudbricks at the lower part of the walls Deterioration of mudbricks at the lower part of the walls

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low. The procedure of the deterioration of the mudbrick continues as long as dampness continues to exits. In the area where the stone base of a mudbrick wall is significantly high, the water may penetrate the inside of a wall through cracks, caused by structural faults or external loading. In some cases cracks develop at the points where timber members and mudbricks meet, due to shrinkage forces or due to the rotting of the timber members. In these cases the damaging process operates only a short period of time (rainy season) contrary to the continuous damaging process of the lower part of the wall especially in stone base walls. Deterioration due to water can also observed at the top of the wall as in this area the structures end and various jointing materials meet (stone, mudbrick, timber, plaster). Cracks may begin to develop in this area due to the different coefficient of expansion of the various materials as well as due to wrong practices and bad workmanship, as well as due to variation in temperature and humidity. The top of a wall is usually protected by a projection of the roof. When this protection fails the water penetrates the structure through the cracks and the materials degrade following the same procedure described above. b. Biological Factors Sometimes birds dig inside the wall to create their nests, exposing the inside of the wall to erosion conditions. When the plaster collapses the holes of the small wooden pins (used for better cohesion between plaster and mudbrick) provide areas for insects and birds to build their nests and also for vegetation to develop, causing internal cracking. c. Mechanical problems Cracks appear when stress overcomes maximum strength. The causes of the cracks are the horizontal movement of the wall, the bending of the wall, and support displacements. Horizontal

Degradation of timber

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movements develop under earthquake, or ground vibrations, strong wing, due to soil or water pressures and because of excessive deformations of the floor or roof structure. Detachment cracks develop because of poor connection at corners. Cracking may also occur from bending. Some of the causes are horizontal movements due to applied forces or displacements or deformations of the floors. Other structural problems of mudbrick walls are bulges, slump or inclination of walls.

IV. Degradation of timber The main damages of timber structural members are the rotting, cracking and loss of strength due to temperature and humidity variations, biological causes and also due to structural problems. Additionally, insects, fungi and other biological processes may create problems and degradation of timber members. The timber members rot usually in areas affected by water and especially in the parts embedded in the walls. The biological causes of wood deterioration are dangerous as some fungi and insects (which develop and thrive from wood) under favorable conditions of humidity (over 20%) and temperature (20300C) cause rotting of the wood. Longitudinal cracks that may be present in wooden members in addition to the reduction of the strength of the members provide nests for insects. Problems in wooden structures can also be created by the physical shrinking of the wood during its drying period and the no-uniform loss of humidity. The use of timber members which have not been properly dried under controlled conditions, or were cut from trees during improper periods with the result that the natural juices remain in the material, may have detrimental results. It is finally noted that most timber members do not have a permanent shape even if they have been cut years ago. With the change of moisture and temperature conditions, they expand or contract and sometimes bend. Under permanent loading conditions they may also be deformed.

Deterioration of mudbricks at the upper part of the walls


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In conclusion it can be mentioned that the main cause of degradation of stone, mudbicks, plasters as well as timber in traditional buildings in Cyprus is water and dampness (rising damp as well as from rain water entering the structures due to structural problems). The protection of the structures can be achieved only by the protection of the structures from water and dampness.

Bibliography IOANNIS, I. (2005), Erosion and Protection of Building Stone, Ornamental Stone from Greece, Hellenic Marble – Hellenic Marble Manufactures. LAMBROPOULOU, B.N. (1993), Erosion and Conservation of Stone. PAPADOURIS, GL. (1990), Building Materials in the Cyprus Traditional Architecture, Archaeologia Cypria.

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PAPADOURIS, GL. (1992), The use of Wood as Inherited in to Building Tradition since Antiquity. Review of the Cyprus Society of Historical Studies. PHILOKYPROU, M. (1999), Building Materials and Construction Methods Employed in Prehistoric and Traditional Architecture in Cyprus, Ethnography of European Traditional Cultures. Arts, Crafts, Techniques of Heritage. Restoration and Maintenance of Traditional Settlements (2003), Cyprus Civil Engineers and Architects Association.

1 The term degradation includes all the processes contributing to the alteration of a stone element. These processes may be chemical, physician, mechanical or biological in nature. 2 It is noted that the solid constituents of a porous material have numerous small vacant spaces, the pores or capillary tubes, which may either be open or closed, forming an internal network. 3

The sulpher oxides coming from the atmospheric pollution, the ground water and the cement plasters, erode the calcareous stones creating gypsum which contributes in a secondary way to the erosion of the stone.

4 The increase of the volume created due to the change of the salts from the anhydrous to the hydrous form increases leading to erosion because of the fatigue which is created by the alternating stress on the walls of the pores. The stress within the stone may reach its breaking point. 5 The process of disorganization of the clay constituents of a material has been described on the above chapter on stone.

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Tool 6 Understanding the processes of degradation of the materials used

Various types of scientific techniques used to identify degradation mechanisms of stone

Mustafa Al-Naddaf Ph.D. in Geology Department of Conservation and Management of Cultural Resources, Yarmouk University, Irbid-Jordan

Introduction

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All materials have a stable state for the environment in which they were formed. A significant change in the environmental conditions, however, may force the material to transform into a material with a new stable state (RAPP and HILL, 1998; MALAGASTARZEC et al., 2000). Stone weathering- defined as the process of alteration of rocks as a result of the adjustment of its internal constituents by the action of physical, chemical and biological factors, to the prevailing conditions of the atmosphere and in the environment (PELLIZZER and SABATINI, 1976; AMOROSO and FASSINA, 1983; KARPUZ and PASAMETHOUGLU, 1992)- is a natural phenomenon that has occurred since the stone was formed and that will continue as long as the stone exists (CHAROLA, 1988 and TURKINGTON, 1996). Monuments and sculptures made of stone have withstood the attack of natural weathering agents for centuries. Yet, during the last few decades, many of these monuments and sculptures, especially near the urban and industrial areas, have been observed to undergo accelerated decay (AMOROSO and FASSINA, 1983; ASLAM, 1996; McALISTER, 1996).

Weathering Agents The alteration of rocks in the lithosphere is produced by various continental (extrinsic) agents i.e. physical (also called mechanical disintegration), chemical or biological, as well as by their intrinsic properties, like their mineralogy, texture and structure (DĂ’SSAT, 1982; AMOROSO and FASSINA, 1983; BRADLLEY and MIDDLETON, 1988; GAURI, 1992; LING et al., 1993a VINCENTE et al., 1993). Thus, stone decay in a monument is rarely a result of just one single factor (process); it is usually a combination of different agents (SCHUMANN, 1998). Different groups of deterioration forms, from which the formation of deposits on stone surface is the most important, can be detected on the monumental stones. It is thought that the deterioration of building stone under the effect of atmospheric conditions usually starts by graying of the stone, often followed by formation of crusts and further destruction by scaling, etc. (Hoke, 1978, and Al-Naddaf, 2002). On many types of stone, a thin layer, 0.02-0.2 mm thick, hard, black, generally without luster, may develop at the surface (Nord

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and Tronner, 1992; Nord and Ericsson, 1993). Different origins have been suggested for the patinas and crusts coating the surface of monuments, these include: treatment for aesthetic and/or protective purposes, biologically induced deposits, interaction with the atmospheric agents, such as SO2, leading to sulphation and the formation of gypsum, and dry or wet deposition of atmospheric particles ( Garcia-Vall?s et al., 1998). Formation of such a layer plays an important role in the variability of the chemical composition of building stone. This phenomenon is normally apparent in near-surface regions where fluids ingress/egress, which can redistribute the compounds with high solubility, and is at its most intense (Hayles and Bluck, 1995). The determination of the composition and origin of the deposits found on the monuments will help to understand the mechanism of the formation of these deposits. This will enable us to adopt preventive conservation measures that may mitigate and retard their formation and also guide us to the best interventive conservation measures to remove these deposits without, or at least with minimal, negative impact on the stone itself (Riederer, 1973). Optical microscopy, X-ray diffraction, scanning electron microscopy, infrared spectrophotometry, ionic chromatography, and plasma and atomic absorption spectrometry tests all can be used in order to characterize mineralogically and chemically the fresh and weathered rock, as well as the stone pathologies in the monuments.


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X- Ray Diffractomettry (XRD) The chemical and mineralogical characterization of ancient building materials is a basic objective of any research involving these materials. Such characterization can contribute important information about composition and alteration products, from which conclusions can be drawn, allowing the estimation for the degree of the materials decay. Consequently, its causes can be evaluated (PUERTAS et al., 1992). In order to determine the mineralogical composition of the stone samples as well as that of the weathering crust, the powder X- ray diffraction method can effectively be applied. With this method; a mineral content higher than 1% can be detected (DO, 2000). For some samples with a high clay content, the oriented X- ray diffraction method is used. Comparing the differences in the mineralogical composition of a fresh stone with that of the crust covering it can be used as another way to determine the origin of this crust. Petrography Thin-section analysis is a very efficient way to obtain crucial information about many inorganic materials. Geologists use thinsection petrography to describe and classify rocks, soils, and sand. Archaeologists and conservation scientists use it to study many inorganic materials used in the production of cultural objects. Purposes of such analyses in cultural object studies include making correct material identifications, grouping similar objects, identifying the geological origin of the object or some of its components, and studying manufacturing technology. For some art materials, structural and mineralogical changes on weathered surfaces in comparison to unaltered interior sections of a sample, may provide information concerning the authenticity of a piece. Thin sections have also been used to study the deterioration of inorganic art and architectural materials, and to check the effects of conservation treatments on those materials. (Reedy, 1994). The most common question about weathering of natural stone concerns the influence of pollutants; to answer this question it is necessary to know as much as possible about the natural stone itself. The laboratory investigations carried out by Holzwarth, 1996, and by Livingston, 1988, showed that physical properties cannot give all of the information about the material without knowledge of the special petrographic properties. In addition to that, the petrographical and diagenetic properties can explain many of the deviations in the physical properties of sub samples taken from the same stone block, taking into consideration that some of these properties can greatly affect the weatherability of building stones. One advantage of thin-section petrography is that the polarizing microscope, needed to conduct such an investigation, is relatively

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inexpensive, making the technique potentially available to almost any laboratory as a routine method of analysis. The cost of purchasing and maintaining a polarizing microscope is much less than for other types of equipment used to study stone objects such as a scanning electron microscope, electron beam microprobe, x-ray diffractometer, or elemental analysis instrumentation (Reedy, 1994). Scanning Electron Microscopy Scanning electron microscopy (SEM) is widely used in the field of material investigations. In this technique, a highly focused electron beam with a nanometer size is scanned over the target area. Observation of the secondary electrons, generated by this beam, offers morphological resolution in the nanometer range (ADLER, 1982; VAN GRIEKEN, 1989; McALISTER, 1996). The kind of insight which the scanning electron microscope provides is important in assessing the quality of the intergranular cementation and the tendency of stone to hold onto imbibed water and to adsorb material from that water. The greater these latter factors are, the more susceptible the stone will be to deterioration due to freeze-thaw, wet-dry cycling and salt crystallization, and the more urgent for the stone to be protected (LEWIN et al., 1978). The deterioration of the building stone as a result of the dissolution of the cementing material is one of the most important

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decay mechanisms affecting these stones. Such a process can be detected by using of the scanning electron microscope, especially if coupled with X- Ray Fluorescence. In humid environments, biodeterioration can be a major factor causing the damage of stone, concrete, mortar, etc.; this type of damage can be caused by such microorganisms as bacteria, fungi, lichens and algae, and plants such as mosses. Whilst bacteria tend to biodeteriorate by etching surfaces due to acid excretion, fungi have also been found to degrade stone, concrete and mortar by penetration of the surface itself. SEM is considered to be the most important analytical technique by which such factors of deterioration can be detected (Tapper, et. al. 1999).

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X- ray fluorescence and Atomic Absorption Spectrometry The most visible products of the weathering of stone materials are a consequence of fragmentation and disintegration of mineral components. Somewhat less obvious, but not less important, is the dissolution of some minerals and subsequent formation of new compounds as a result of the action of chemical and biological agents, processes which can lead to alteration of the chemical properties of surfaces exposed to the environmental effects (ADLER et al., 1982; McALISTER, 1996). Consequently, determination of variations of the chemical composition of weathered surfaces in relation to their unweathered fresh zones is an important analytical method by which the deterioration agents may be identified, while conservation strategies can be established accordingly. For the investigation of elemental composition of inorganic materials, either in fresh or weathered state, the instrumental methods of X- ray fluorescence analysis and Atomic Absorption Spectrometry are often applied with great success (MARINGER, 1982). They can be used to determine the concentrations of the major oxides: Na2O, MgO, Al2O3, SiO2, P2O3, SO3, CaO, K2O, TiO2, MnO and Fe2O3, as well as some trace elements: Zn, Rb, Cr, Sr, Zr, Ba and Pb. Comparison between the chemical composition of the weathering crust with those of the internal fresh stone will enable us to identify the origin of encrustation on the stone facades. Such comparison can be statistically processed by using the enrichment factor (Ef) concept (reference).

Ion Chromatography When present in considerable quantities in the ground, soluble salts can cause more damage to a monument than perhaps any other natural deterioration factor (PLENDERLEITH, 1979). Salt weathering affects rocks, building stones, mortar, bricks,

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paintings, glasses, and many other porous materials used in buildings and monuments. Thus, it is actually recognized to be one of the most frequent and effective weathering agents (ARNOLD, 1976a, b; ARNOLD and ZEHNDER, 1989). Several types of salt minerals can be detected on buildings. The most common salts occurring in building stones include sulphates, nitrates, chlorides and carbonates of sodium, calcium, potassium and magnesium. Ion chromatography is a form of liquid chromatography that uses ion-exchange resins to separate atomic or molecular ions based on their interaction with the resin. Its greatest utility is for analysis of anions for which there are no other rapid analytical methods. It can be said that Ion Chromatography is one of the most important techniques which can be applied to determine the concentration of Cl-, NO-3 and SO4-2 in stone samples.

References Garcia-Vallés M., Vendrell-Saz M., Molera J. and Blázquez F. (1998): Interaction of rock and atmosphere: patinas on Mediterranean monuments. Env. Geol. 36: 137149. Springer-Verlag. Hoke E. (1978): Investigation of weathering crust on Salzburg stone monuments. Studies in conservation. 23: 118-126. Hughes M. J., Cowell M. R. and Craddock P. T. (1976): Atomic Absorption Techniques in Archaeology. Archaeometry. 18: 19-37. GB. Riederer J. (1973): Die Erhaltung vo Kunstwerken aus Stein in Deutschland. Maltitechnik-Restaurato.1: 73. Reedy, Ch.: Thin-Section Petrography in Studies of Cultural Materials. JAIC 1994, Volume 33, Number 2, Article 4 (pp. 115 to 129) Tapper, R.; Smith, J.; Beech, I.: Modern Microscopy techniques for the Study of Mortar Biodeterioration, Poster presented at International conference on microbiology and conservation (ICMC ’99) Of microbes and art: The role of microbial communities in the degradation and protection of cultural heritage. Tribuna di Galileo, Museo della Specola, 16-19 June 1999, Florence, Italy, pp. 180-184.


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Agents in timber degradation

Professor in the Department of Architectural Technology II, School of Building Construction of Barcelona (Technical University of Catalonia), Spain Given the right conditions, wood is a long-lasting material. The same might be said of many other construction materials, though others have yet to prove it. We find timber elements in a perfect state of conservation in buildings that are centuries old. There are many others that, as a result of deterioration or complete destruction due to an inability to resist outer aggressions, have been replaced or become the cause of the ruin of buildings. Wood has many enemies (agents that degrade or destroy it) but the choice of appropriate construction solutions can provide protection. Suitable maintenance of wood that forms part of a building can extend its useful life to the extent that, in present-day terms of the duration of buildings, we might consider it eternal. The elements of which wood is made (cellulose, lignin and others) attract various types of living beings from the plant and animal kingdoms in search of food. Non-biotic destructive agents include atmospheric agents: solar radiation, rain and, due to its great potential for destruction, fire. Each degradation agent produces a type of attack of an intensity that causes different effects, and they are not the same for all types of woods.

Agents that degrade wood As explained above, the agents in wood degradation tend to be classified into two main groups: abiotic and biotic agents. The abiotic agents include solar radiation, rain and various kinds of damp, fire and, finally, chemical products. The living beings in question are, on the one hand, plants, such as fungi, and, on the other, insects.

Abiotic agents of degradation Solar radiation Of the broad spectrum that makes up solar radiation, it is the fractions of ultraviolet and infrared radiation that most affect wood, particularly the former. Ultraviolet radiation principally affects the surface of the wood, generating a series of chemical alterations that particularly degrade lignin, breaking it down and producing a characteristic

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Joaquín Montón Technical Architect Professor in the Department of Architectural Technology II, School of Building Construction of Barcelona (Technical University of Catalonia), Spain

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Abiotic degradation of wood.

greyish colour due to the greater presence of cellulose. If no action is taken to protect it, the process continues, rain will then wash away the cellulose, giving rise to the appearance of a characteristic relief on the surface, with wood in the spring, which is not so compact, being less affected than in the summer. If fungi spores are placed on the surface, they will cause superficial degradation, producing a change in coloration to dark grey or black. Nonetheless, the degradation produced by this kind of radiation is very slow and only works at very shallow depths. Infrared radiation does not degrade wood directly. It heats the surface, causing a decrease in humidity of the wood’s surface, which is usually accompanied by contraction. This heat increase does not affect the inside of the wood in the same way, so the temperature remains lower and does not produce a decrease in humidity, and the wood therefore does not contract. The resulting tensions between the surface, which tends to contract as its dries, and the inside, whose moisture content and therefore dimensions remain the same, give rise to shakes on the surface, generally relatively minor. The effects of solar radiation can be reduced by applying surface protection. This may take the form of paint, varnish or stain, and the best results are produced by high pigment content. These protective products are also degraded, losing their capacity to protect, and therefore have to be renewed when they cease to carry out their task correctly.

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Rain Rainwater produces increases in moisture in the outer layers of wood. This increase in moisture takes place very fast with no corresponding variation in the inner layers. These differences in moisture content between the different parts give rise to tensions that are reflected in distortion and even the appearance of shakes. Furthermore, as explained above, they facilitate the elimination of the lignin and produce superficial alterations. Finally, as we will see below, most biotic attacks need a high moisture content to develop, and this may be provided by rainwater.

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Fire If one thing is obvious, it is that wood burns. Many other construction materials do not, though this does not mean that they do not lose some or all of their properties on contact with fire. Wood comprises primarily cellulose and lignin, whose basic component is carbon. Although wood burns, a series of particularities should be mentioned. Firstly, when it burns, it reduces in section and may be destroyed. This, however, is a slow process due above all to three factors: moisture content, the carbonization of the surface and low heat conductivity.

Tool 6 Understanding the processes of degradation of the materials used Agents in timber degradation

section (the thinner it is, the faster it burns), position (vertical elements burn more easily) and moisture content (green wood takes far longer to burn than dry wood).

Biotic agents of degradation Numerous living beings, called woodborers, feed on wood. These are fungi and insects that degrade and even destroy wood by eating some of its components. In an attempt to simplify this section, they are grouped not just by origin but also by similarity of the attacks or degradation they represent for wood. We will use the following scheme for greater clarity:

Mould

Chromogenic fungi Fungi

Blue stain Brown rot

Rot fungi

White rot Soft rot

Lyctidae

Moisture: As the wood is heated, it loses moisture, thereby consuming a degree of calorific energy. Furthermore, as the moisture content falls, the wood’s mechanical resistance increases.

Larva cycle: Coleoptera

Anobiidae

Insects Cerambycidae Social: Isoptera

Termites

Carbonization of the surface: When no water remains, the combustion mechanisms begin. This text is not the place to give a detailed explanation but for our purposes suffice it to say that surface carbonization is a slow process that slows the penetration of heat into the interior, forming a heat barrier that acts as insulation. This also hinders emission of the inflammable gases generated inside the wood.

Fungi

Heat conductivity: Wood has low heat conductivity, as a result of which burning wood maintains relatively low interior temperatures without losing its mechanical characteristics. At a given temperature, steel softens, behaving like a plastic material and causing its structures to collapse. Concrete undergoes a series of alterations that reduce its strength and are closely related to the type of aggregate and cement used, which can be aggravated by the sudden cooling caused by the water used to extinguish a fire. Not all woods burn the same. Conifers tend to burn faster than broadleaved trees, mainly due to their resin content. Lightweight woods generally burn faster than heavy ones. Other factors are

Fungi are lower plants, with a very primitive cell organization (simple), made up of microscopic filaments called hyphae. They do not have stalks, roots or leaves, and do not produce chlorophyll, which obliges them to feed on dead organic matter or on other living beings as parasites, feeding on existing organic compounds. In order to develop on wood they need a high water content, at least 20%, and temperatures of between 20 and 25ºC for optimum growth. Among those that live on wood are fungi that merely change the wood’s colour (moulds, chromogenic fungi) and those that bring about a major change in physical and mechanical properties (rot fungi).

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Mould Mould feeds on the content of the surface cells of wood, as it is not capable of attacking either the cellulose or the lignin, and therefore do not affect the wood’s mechanical properties. It can be detected when it forms spores, generally dark in colour, on the surface of the wood or when it forms a kind of down. Normally it only forms on the surface and can be removed by rubbing. Chromogenic fungi Like mould, these fungi barely degrade the cell walls. They feed on products that exist in the sapwood and do not generally affect the heartwood. The most representative is the blue fungus which, unlike mould, penetrates into the wood and cannot be easily eliminated. Although it does not affect the wood’s mechanical properties, it increases its hygroscopicity, encouraging the appearance of more destructive rots and also gives wood an appearance and a colour that makes it useless for joinery and decoration. It is very common for wood to be contaminated with its spores in sawmills, since tree trunks have a very high moisture content and a great deal of sap. To prevent attacks, it is sufficient to briefly immerse the sawn wood in a tank of protective product. This treatment involves just a small increase in the cost of the wood and eliminates the problem. Rot fungi These fungi produce enzymes by means of which they destroy the wood’s cell walls, decreasing their mechanical resistance to zero in some cases. They also alter the colour and decrease the wood’s density. They are extremely dangerous in structural elements. The conditions for their development vary from species to species, but they always need high moisture levels and a specific temperature. By keeping the wood dry, practically all risk of rot is eliminated. There are many types of rot fungi. Here, briefly, they are grouped by the alterations they produce in wood, which can normally be identified by the appearance and colour of the attacked wood. Brown rot (Basidiomycetes) The fungi that cause this attack feed basically on the cellulose, leaving the brown-coloured lignin that falls into characteristic cubes. The loss of resistance can be complete, so that the wood crumbles to the touch. White rot (Basidiomycetes) The fungi that cause this attack feed basically on the lignin, leaving the white-coloured cellulose. The fibrous residue that remains after the attack crumbles to the touch. This type of rot affects the woods of broadleaved trees more than conifers.

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In both of these last two cases, the wood may remain unaltered to the eye until it reaches a very high level of degradation and weakness, which makes these fungi very dangerous. Soft rot (Ascomycetes) Produced by lower fungi, ascomycetes, whose hyphae develop inside the cell wall, it feeds principally on the cellulose in the cell walls when moisture levels are high, leaving the wood with a soft consistency. It tends to be found in timber elements in contact with the ground. Insects Insects that feed on wood, thereby degrading or destroying it, are divided into two main groups: larva-cycle insects, mainly Coleoptera and social insects, Isoptera. They are some other insects, such as the wood wasp, carpenter bee and wood-boring crustaceans, which have less of an effect. Larva-cycle insects These are insects which, in the course of their lives, undergo metamorphoses, passing through the instars of egg, larva, pupa and adult insect. During the larva instar, the insect lives inside the wood, feeding on it. The larvae develop inside the wood, where they continue to feed, creating a network of tunnels. The cycle begins when the adult insect lays the eggs in fissures and cracks in the wood. Larvae hatch from these eggs and begin to feed on the wood’s constituent elements, thereby creating tunnels. As the wood is hollowed out, it loses strength, the rate varying according to the species in question. For greater simplicity, below they are classified according to three groups corresponding to the size of the larvae and the gravity of the attack, from lesser to greater. Lyctidae (powder-post beetle) Lyctidae are fairly small insects. The larvae measure 4 or 5 mm at most. They feed principally on the sapwood of broadleaf woods that meet certain conditions as regards the diameter of their vessels and the minimum starch content. Their life cycle is about one year and may be shorter depending on conditions. They drill tunnels parallel to the fibres, which fill with a very fine powder, and emerge to the exterior via small circular holes, of 1 to 2 mm. This group includes Lyctus brunneus Stephens and Lyctus linearis Goeze. Anobidae (woodborers) This group is generally known as woodborers, the most representative being Anobium punctatum De Geer. It principally attacks the sapwood of conifers and European broadleaf trees and, if conditions are very favourable, they may also attack the heartwood. The larvae grow as long as 5 mm. The life cycle of these insects

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Tool 6 Understanding the processes of degradation of the materials used Agents in timber degradation

Persistent attack by anobiidae

Anobiidae larva (Photograph: Teresa Mach Farina, biologist)

may be three years or more, and this is therefore the time that may pass before discovering that the wood has been affected. Until after this period, the larvae do not emerge to the exterior to complete their life cycle, when they transform into complete insects. The exit holes measure between 1.5 and 3 mm in diameter. The sawdust found in the tunnels they bore in wood is coarse and granulated. Also included in this group is Xestovium rufovillosum De Geer, similar to the Anobium but with larger larvae, up to 11 mm. The circular exit holes may be as large as 4 mm. They attack the sapwood of broad-leafed trees with high moisture content that have previously been attacked by rot fungi. They produce sawdust in the form of disks, which is sandy to the touch.

Cerambycidae The best known is Hylotrupes bajulus, commonly known as oldhouse borer. It attacks the sapwood of conifers. In optimum conditions, its life cycle may be longer than 10 years, which, together with the fact that it is much larger than all of the above, means that the damage produced when its presence is discovered may be considerable. The larvae may grow to 22 mm in length and 6 mm in diameter, and create oval holes of as much as 7 mm in diameter when they emerge to the exterior. Their capacity to destroy wood is considerable, much greater than the previous two cases, requiring similar treatment to eliminate them as termite attacks and some cases of rot.

Reticulitermes lucifugus, worker and soldier (Photograph: Teresa Mach Farina, biologist)

Reticulitermes lucifugus, secondary reproducer (Photograph: Teresa Mach Farina, biologist)

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Anobiidae adult (Photograph: Teresa Mach Farina, biologist)

Cerambycidae larva (Photograph: Teresa Mach Farina, biologist)

Social insects. Isoptera (termites) The insects that produce most damage in wood, belonging to the order of the Isoptera, are termites. Termites live in highly organized and specialized colonies. There is a queen, whose function is to reproduce, workers, soldiers and neotenic reproductives (if for some reasons this group loses contact with the nest, they may create a new one and become reproducers). Of the species that exist in our context, the most important is Reticulitermes lucifugus Rossi. Their main nest is situated underground, where they find the temperature and moisture level they need, normally at some distance from the buildings attacked.

They feed on the sapwood and heartwood of conifers and broadleaved trees, provided they have a high moisture level. They bore tunnels in the direction of the fibres, always leaving untouched an outer layer to protect them from the light and the loss of moisture from their environment. The tunnels fill with a residue of a characteristic earthy consistency. They are very difficult to locate because they leave no sign of their presence. If they are unable to continue their way inside walls or beams and have to emerge to the exterior, they build tunnels using organic waste and earth that allow them to continue on their way in the appropriate moisture conditions, protected from the light. These cordons are one of the few external signs giving clues as to their presence. They are highly destructive and both

Kalotermes flavicolis, worker (Photograph: Teresa Mach Farina, biologist)

Kalotermes flavicolis, secondary reproducer (Photograph: Teresa Mach Farina, biologist)

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difficult and expensive to eliminate. In some places, they are so abundant as to be considered almost a plague, and produce serious damage that is very costly to repair. Other species of termites in our field of activity are the Cryptotermes brevis Walker and the Kalotermes flavicollis Fabre, which are less numerous than the Reticulitermes.

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Termite tunnel on a plastered wall

Termite attack behind a wood-fibre skirting board

Distribution of the different varieties of Reticulitermes in the north-western Mediterranean

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Tool 7 The criteria of intervention

Criteria of intervention in traditional architecture.

II. Reflection and the Project

Fernando Vegas Doctor of Architecture Professor in the Department of History and Theory of Architecture, School of Architecture of Valencia (Technical University of Valencia), Spain Camilla Mileto Doctor of Architecture Professor in the Department of History and Theory of Architecture, School of Architecture of Valencia (Technical University of Valencia), Spain

What are criteria of intervention? No study, however thorough and multidisciplinary it may be, and no methodology of intervention, however serious and rigorous it appears, can guarantee correct intervention in the process of architectural rehabilitation, whether monumental or traditional vernacular. Highly detailed preliminary studies of a building may on occasion correspond to subsequent interventions that completely ruin its essence or distort its character. Examples of this well-intentioned but ultimately blameworthy attitude are very frequent in the discipline of restoration. This is the case because the restoration discipline is not a science. The preliminary studies applied to the building are taken from the more advanced branches of science, which every day draws a little closer to in-depth knowledge of matter and its history. But this is where science ends. From here on, the rehabilitation project belongs to another disciplinary field that is unprotected by the credibility and impartiality of science. The rehabilitation project constitutes a leap in the dark between this scientific knowledge and the effective recovery of the building. Proof of the absence of scientific causality in the project is the fact that a single preliminary study, conducted with all the rigour and means available to us, can illuminate a whole range of projects of intervention related only by the fact that they address the same building. What chance, then, is there of developing a restoration project that is respectful of the architectural object, if all the preliminary studies and methodologies of intervention in the world cannot guarantee the correct course for the restoration project? This is where the notion of criteria of intervention comes in. The aim of these criteria is to precede the project and guide the planner’s actions. They allow us to bridge this gap between knowledge and the physical recovery of the building with some guarantee of success. Criteria precede the preliminary studies. The architect cannot carry out a preliminary study or apply a given methodology as though he or she were mechanically or half-heartedly following a cake recipe. The architect will always undertake a given preliminary study or follow a given methodology guided by these criteria; they

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Sometimes nature appropriates vernacular architecture, making it part of the environment. House in La Pobleta de San Miguel (Castellón, Spain).

are the product not of his or her mental or emotional state, but of collective reflection that reaches beyond personal will. These criteria are not arbitrary, nor random, nor subject to whim, circumstance or the free will of the architect. Criteria of intervention do not constitute the project options; they do not correspond to predetermined images or typologies and are not techniques to be implemented in the intervention process. They precede knowledge of the concrete case of the building to be restored and are ultimately based on the specific circumstances of each case. There are parameters in the discipline of restoration that serve to guide these criteria, such as the experiences of other buildings with their successes and failures, historical debates, the theoretical

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and practical reflections of the masters of the discipline... This reflection on the need for criteria of intervention as an essential factor in the restoration process, over and above all kinds of preliminary studies and the most rigorous and advanced methodologies, is applicable to both monumental and vernacular architecture. Furthermore, in the rehabilitation of traditional architecture, criteria of intervention become even more important since, on many occasions, the absence of the means to carry out preliminary studies or the geographical and cultural distance of the most acute methodologies approved by the theorists of the discipline prevent their literal application to the most habitual specific cases. In this respect, clarity in criteria of intervention is more essential than an infrastructure of knowledge and a manual of phases of action. 7

Criteria in traditional architecture Traditional vernacular architecture is created in close association with the landscape, the product of a sound combination of the material available in this context according to the construction systems and artisan techniques created by its residents over the generations, responding to strict functionality. Similar environmental conditions generate traditional architecture solutions with similar logics, but there are still as many families of

By simply cleaning a historical façade it is possible to conserve all the charm of its materiality, texture and patina that would disappear completely if the render were replaced. Old waggoners’ inn in Torrebaja (Valencia, Spain).

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traditional architecture as there are climatic, material and sociofunctional environments. The advent of industrialization completely changed the conditions of production of popular architecture, increasingly linked not to the raw material of the place, but to commercial construction materials. In many corners of the globe, traditional architecture has ceased to exist as an active phenomenon. In the rest of the world, it survives in association with isolation and scarcity of means, but its abandonment is foreseeable in the short and midterm, and this is why we are now studying its conservation. In general, given the difficulty today of reproducing the spontaneity and naturalness of the builders of traditional architecture, it should be conserved, since it is not in our power to generate new examples. Traditional construction has in many places peaked and can now only decrease. Within the range of possible criteria for the restoration of this disappearing architecture, once it has ceased on a large scale to be reproduced as a species, there are some simple parameters to be taken into account to allow a generous extension of its useful life, at the same time safeguarding its integrity. Materials The materials of traditional architecture must be conserved as far as possible. They merit protection on two counts, since they reflect two factors of traditional architecture: its composition or the mass that comprises it, and its character, expressed by its external


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surface. Stone that is slightly worn or dotted with lichens, veinysurfaced wood, plaster and renders, woven cane, rammed-earth walls, etc., constitute the outer and inner envelope of the house, and their transformation carries with it much of the character of traditional architecture. Traditional architecture is most likely to survive a process of rehabilitation if care and delicacy are applied when replacing materials and concealing its surfaces. Obviously, rehabilitating a dwelling to contemporary standards has to strike a compromise between the needs of habitability and conservation of the materials. The materials were handmade by their constructors and, in the absence of knowledge of vernacular techniques, they must be conserved for their naturalness and spontaneity and as a record of the construction tradition of the past. The existence of roofs made of plant matter (straw, reeds, bark...) requires periodic replacement due to the perishable nature of these materials, as has happened since remote times. In these cases, the inclusion of extra waterproofing protection beneath the plant layer contributes to its maintenance and extends the period between replacements. Another option in this case which, though not as recommendable is still acceptable, is to replace a roof made of plant matter with another, more lasting type of traditional roof, generally made of tiles. This type of transformation has always occurred in traditional architecture and has proliferated in recent times. Hybrid vernacular architecture is always preferable to its complete disappearance. The surfaces of traditional construction may be affected in a variety of ways, including the addition of wall insulation, the creation of chasing to house installations that is then plastered over, changes in a building’s distribution and so on. These changes may be necessary, but their indiscriminate, generalized acceptance ultimately transforms the overall appearance of traditional architecture. It is necessary to find a compromise between the conservation of surfaces that give a construction its character and the inclusion of new installations by seeking solutions that are as respectful as possible of the materiality of traditional architecture. The new materials to be introduced into rehabilitation must be compatible with the existing construction, not only physically but also in chemical and, most of all, conceptual terms. In this way, for example, if waterproofing or an extra layer of insulation is added beneath the protective plant, ceramic, clay or stone layer of a roof, they must be breathable to prevent condensation inside and, as applicable, to allow the evacuation of water vapour through vents. In the case of having to plaster the external or internal surfaces of the house due to a pressing need that justifies the loss of quality or vibration of these traditional surfaces, the mortar used should not only be breathable, it also has to be flexible. Cement mortar

II. Reflection and the Project

is a clear example. In general, it is the worst mixture that can be used to render the inside or outside of a wall, for two reasons: its lack of breathability and its excessive rigidity in traditional walls, whatever their material components, which can ultimately ruin them. In this respect, it is also possible to apply the general rule that the renders applied to traditional walls (rammed earth, adobe, stone, brick, timber structure...) must be less rigid than the material they are covering, as has traditionally been the case in vernacular architecture. This guarantees the future integrity of the fabric, as the render will fall off before the wall beneath it collapses. The materials used to rehabilitate traditional architecture must also be compatible with the health of its residents. The sustainable, ecological nature of traditional architecture by definition must not be compromised by the inclusion of new materials that enter into conflict with the natural philosophy and wholesomeness of the existing materials. Structure Just as the materials are the flesh, the structure constitutes the bones of the architecture. The framework of traditional architecture is the product of optimizing local resources, and it usually responds to the centuries-old characteristics derived from its constituent material, the earth on which it stands and any meteors and earth movements there may have been. According to John Warren, there are three possible options when rehabilitating the structure of traditional architecture: repair, reinforcement or replacement. The structural elements may be timber beams, joists or purlins, pillars, a fabric of masonry, adobe or rammed earth. We will examine these three options, taking as an example a timber beam.

The character of the architecture is reflected by its external surface. It is therefore a good idea to gauge the effects of intervention on it. Detail of a façade in La Pobla de Benifassà (Castellón, Spain).

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Repair consists in cutting out the rotten part of a wooden beam and replacing it by a piece of new timber. The importance of the concept of repairing the structure lies in the conservation not just of its materiality but also of the original structural system, which remains in use. In this case, the introduced material must blend harmoniously with the pre-existing elements and be possible to tell apart, if necessary. Reinforcing a weak beam consists in inserting elements of support, traditionally iron. This option is used when it is necessary to increase the loads architecture can bear. Repair maintains the

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building’s original strength, whereas reinforcement increases it, for reasons of physical change, new legislation or a change in function. In this case, the reinforcement should not be accorded protagonism over the original structure. Unlike repair and reinforcement, the replacement of a beam or another construction element, even if it is a copy of what was there, does not conserve the materiality of the original. The lower the proportion of elements replaced, the more delicate the treatment given to traditional architecture. In this case, efforts should be made to conserve at least the structural principle of the building, which is as important as its materiality. In this respect, the requirements of present-day regulations with regard to structures and earthquake resistance can be approached in two diametrically opposite ways. If we ignore the existing structure and entrust compliance with regulations to a reinforced concrete structural floor, whether or not it acts compositely, we are seriously distorting the traditional structural principle. Traditional structures tend to be isostatic, so the introduction of a hyperstatic material like reinforced concrete renders the whole rigid, presenting a latent threat to the survival of the house due to

Replacement of a roof of plant material after an arson attack. La Genuina rural construction in Pinedo (Valencia, Spain).

Although not recommendable, it is still preferable to replace a roof of plant material by another type of roof on the market rather than demolish the building. Ricart-Navarro rural construction in Pinedo (Valencia, Spain).

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By repairing beams using new made-to-measure parts, much of the building’s original materiality can be conserved. Church of La Pobla de Benifassà (Castellón, Spain).


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its added weight, lack of flexibility and lack of seismic performance. If we simply improve the strength of the existing structure with appropriate metal or wooden reinforcements that act compositely with it, we are maintaining the structural principle that characterizes the original building, at the same time contributing to its ability to meet the required objectives. These dry-assembly reinforcements are also perfectly compatible with the existing structure, unlike liquid reinforcements such as concrete, which produce irreparable damage to the timber of the beams, joists and

II. Reflection and the Project

sheathing or to the plaster of the structural floors, which become food for insects, fungi or rot, as well as undermining their intrinsic resistance. Function The fundamental criterion that has always governed the discipline of restoration is this: both traditional and monumental architecture has to have a function in order to guarantee its continuing existence. It is therefore necessary to adapt the building to contemporary living standards. First, we have to present a reasoned exploration of the compatibility of the old and the new functions and ensure that the building’s surface area is not being used beyond its natural capacity. In both cases, it is difficult to successfully undertake a restoration project, even if we take all the precautions and apply the sensibility described here. If it is a housing project, the dwelling must meet the same conditions of habitability as those required of a new dwelling. This means soundproofing and insulation to regulatory levels, ventilation and lighting with glazed windows if these do not already exist, a completely waterproofed roof, and the existence of a kitchen, bathroom and heating as applicable. For all of these requirements, an agreement of commitment may be necessary to allow a degree of flexibility of interpretation of regulations, on the basis of the house’s pre-existing conditions. Making a window larger to achieve better ventilation and/or lighting may ruin the exterior façade, and it is therefore necessary

A post-stressed reinforcement of a deflected timber beam can give it a new lease of life and even make it stronger than it was when original built.

The Wine Museum in La Puebla de San Miguel (Valencia, Spain), installed in an old press in the town, has proved to be perfectly compatible with the previous function.

Dry consolidation of a timber and plaster structural floor prevents the irreparable damage caused by the compression layer on it. Building in Valencia’s seafront district (Spain).

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to weigh up all the existing possibilities of distribution and compliance with regulations before distorting the exterior façade of a traditional building. The functional adaptation of a traditional dwelling to present-day standards calls for particular attention to telecommunications, as the diffusion of electronic communications and the proliferation of the concept of teleworking require the incorporation of these new media into the restored building. It only makes sense to turn a traditional building into a museum piece if the function for which it was created has ceased to exist. This option is possible and plausible if there is no other more active alternative. However, this treatment must not extend to the rest of the traditional settlement. An entire village cannot be turned into a museum; it would merely become a kind of artificial theme park or stage set, even if the constructions were real rather than the plasterboard they tend to be in both cases. It is possible for some traditional buildings to become museum pieces while the rest of the residential fabric maintains its usual function. Relation with the context The restoration project must respect and conserve this relation, which is biunivocal in the case of traditional architecture. The external image of traditional architecture is closely related to the landscape that surrounds it, because its scale, materials, colours and texture are taken directly from it. Traditional architecture requires the conservation of its surroundings to justify its constitution and presence, and the surroundings call for the conservation of the only kind of architecture guaranteed to be fully compatible with it—the traditional architecture to which it gave birth. The criterion that seeks to conserve a given image does not respond to bucolic sentiment or nostalgia for the atmosphere of traditional architecture, which seek to capture the world in a primitive state at a given moment or time. The image of traditional architecture and, by extension, of traditional settlements, possesses a series of values relative to its dimension and human scale, its integration into nature and its unconscious application before the fact of the principles of ecological architecture, which must be recognised and appreciated. For this reason, the restoration of traditional architecture has to respect the criterion of conservation of its usual image, which is the product of centuries of optimum use of the construction materials and techniques of the place. If it is necessary to incorporate an annexe or new construction in a context of these characteristics, strongly marked by traditional architecture, the project should seek to integrate volumes, colour and texture in such a way that the new building goes unnoticed in the settlement as a whole. Likewise, rather than being a reactionary, utopian or romantic attitude to the natural landscape, the criterion of conservation of

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the surroundings represents the will to preserve the natural landscape that produced the traditional architecture. Conservation of the environment is surely compatible with a reasoned use of the natural means and resources that considers not only net economic profits but also economics in a wider sense, taking into account other factors such as culture, history, sustainability, ecology and identity. Restoration of traditional architecture cannot be taken independently of its surroundings and the landscape that produced it. The painstaking preservation of an architectural object apart from its historical and cultural context, due to excessive transformation of the latter, is always commendable yet insufficient from the viewpoint of the integrated conservation of traditional architecture. Implementation The criteria of action in the field of restoration of traditional architecture not only have to be present before work starts on the preliminary study or when drafting the project, they also form an integral part of the physical restoration work. The implementation of all the studies and the ideas brought together in the project may justify all the hard work carried out in this process, but it could also very easily ruin it. For this reason, it is important not to lower one’s guard during on-site work. There are three main fronts of attention for the architect during the implementation of the project: the building, the workers and the processes. The traditional building must remain at the forefront of attention throughout the restoration process, which

There is little point restoring individual buildings if at the same time the surroundings are irretrievably modified. A rare view of Ademuz (Spain), showing the integration of its architecture into the mountainside.


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may produce data not sufficiently clarified by the preliminary study, issues not envisaged in the project, or corrections and nuances to be considered on site. Even the best project cannot foresee every incident that will emerge during restoration work, but the more work done on a project, the greater the guarantee of good results and the fewer the problems. The main criterion when restoring traditional architecture must then, be to carefully monitor the work after comprehensive reflection on the project in order to respond to unforeseen events on site. The workers, as actors in the implementation of the restoration project, must share with the architect in the aims of the intervention, otherwise they may simply not become involved in producing the best possible outcome. It is important to invest the necessary time in explaining details and reasons, and the overall aim pursued by restoration work. It may on occasion be necessary to explain the appropriateness of construction processes and techniques that are not habitual for the workers but are necessary for the restoration of the building. It is therefore essential when choosing workers to ensure that if they are not familiar with the processes to be used, they are at least open to new ideas and can adapt easily to the orders given by the architect. The construction processes are very important to the finished appearance of the restored work. Traditional architecture is characterized by being the spontaneous, natural work of artisans, rich in textures and human nuance. The indiscriminate, direct application of industrial solutions can ruin this spontaneity. It is therefore important to rework all of these solutions and adapt

The criteria addressed in the project must be carried over to the site work, which is the acid test of these initial ideas. Traditional house in Sesga (Valencia, Spain).

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their composition, application and use to traditional architecture. Commercial and industrial solutions have to be digested in a process in which the architect’s criterion has to assimilate, improve, hybridize and transform them to ensure that their entry into the fragile context and matter of traditional architecture is silent, discreet and respectful of its delicate intangible character.

The project If it is not possible to carry out some or all of these studies due to lack of available means, visual observation of the traditional building and mental application should be used to prevent the project taking the wrong course. For example, leaving to one side the complementary studies that require specialized professionals, if scale plans of fissuring, mapping or pathologies are not undertaken, they can be observed, noted down or marked on photographs and, above all, taken into account in the project. The unavailability of any particular type of means to carry out these studies in orderly, official, scrupulous fashion does not exempt the architect from the necessary mental and methodological processes before undertaking the restoration project. It is not common but it does occur that having carried out a comprehensive preliminary study of the building or drawn hasty conclusions as to its structural behaviour, construction problems and various pathologies, the architect may feel qualified to perfect the building’s history, adding finishing touches or correcting supposed defects. To avoid this eventuality, the path to knowledge represented by the preliminary study must be trodden with humility, respect and caution, the same virtues that will later guide the application of the project. A project to restore a traditional building has to walk a fine line between conserving as much of the fabric as possible and adapting the building to today’s standards of habitability. The supposition of conserving the material building to uphold the dignity of its structural and constructional function must also, as far as possible, extend to the external and internal surfaces that transmit all the character of the traditional building to the observer and the inhabitant. Types of projects There are basically three types of rehabilitation project that address a traditional building from the viewpoint of use: (1) those that maintain the building’s original function; (2) those that transform it for another active function, and (3) those that turn the traditional construction into a museum piece. Even taking as our departure point an appropriate balance between the surface areas of the traditional building and a new programme that does not speculate on an inappropriate use of it, each of these options can avoid or generate a variety of conflicts.

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Projects that maintain the building’s original function have most chance of avoiding conflict. If rehabilitation involves a traditional dwelling being used as a contemporary home or an old waggoners’ inn as a rural hostelry, then essentially it should incorporate as discreetly as possible the characteristic installations of present-day standards of living (electricity, plumbing, bathroom fittings, kitchen, heating, etc.) and, as far as possible, improve the building’s waterproofing, soundproofing and insulation. Projects to completely transform the building’s original function have to beware of distorting the structure, distribution and philosophy of the traditional building. For example, the transformation of an oil press or an old distillery into apartments may threaten the large interior spaces and the fenestration of these buildings due to the necessity of dividing them up. In this case, the effects of fitting installations, waterproofing and insulation are simply incomparable with the damage caused by forcing the original conception of buildings designed for other purposes. Finally, projects that turn a traditional construction into a museum piece have the advantage of easily adapting their layout and functional needs to pre-existing elements, without having to force or distort them. For example, once the original function is past, the rehabilitation of a mill or press for expository or ethnological purposes respects the building’s structure and at least evokes the original. The problems in this case may arise from regulations for the use of public spaces that do not bring a flexible attitude to the existing building and seek to rigorously apply all of their articles. Compliance with regulations One of the most difficult problems when adapting a traditional building for contemporary use is compliance with regulations governing habitability, accessibility, fire safety, and so on. In some countries, these regulations are very understanding, respectful and flexible in their approach to existing buildings, giving a degree of precedence to historical issues above regulatory stipulations. Others impose rigorous observance, whether the building in question is old or a new construction. There is an answer to all the requirements of regulations, but the architect has to apply all of his or her efforts and imagination to finding the option that least affects the original structure of the building. If this is not sufficient, they must use their best powers of reasoning to convince the authorities of the need to conserve certain of the building’s characteristics, or agree on a compromise of conservation with slight transformations by way of compensation. For example, a balcony railing that is too low can be extended with a supplementary element. The accessibility of a residential stairway can be improved by rational

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redistribution or compensation of the existing steps. It may be impossible to respect a traditional stairway in public premises which calls for a new regulatory staircase, but the old stairs can at least be conserved alongside the new ones. Contrary to appearances, wood used for the horizontal structures of traditional constructions is a splendid material in the event of fire, provided it is thick enough in section to allow the safe evacuation of the building’s occupants in a given time, which constitutes the basis of all fire regulations. In the event of it not having this section, it would be sufficient to supplement it to bring it up to regulatory fire resistance levels. The lack of lighting or ventilation of some spaces can be resolved by means of windows built into the slope of the roof, large double doors with glazing, mechanical extractors, etc. The opening of an emergency doorway to the outside in the case of a public building can be resolved by modifying the fittings or changing the position of the jamb. And so on—there are many possible alternatives that allow the conservation of much of the material and spirit of a house. Spatial distribution The new project layout must above all address the existence of the building’s previous distribution and seek to adapt as far as possible to the logic of the original functioning to avoid distorting its structure. In some cases, preferably in the preliminary study phase, the building’s incompatibility with the planned function has to be recognised, either due to lack of space or fenestration, or to the inappropriate subdivision required by the use of its internal spaces. Maintenance where possible of the existing layout is, in any case, a contribution to savings in the intervention, avoiding the superfluous demolition of walls, stairways and other elements, and their new construction in different positions. It also maintains the character of the building’s inner spaces. Choice of materials The choice of new materials to be used in the restoration of the traditional building must take a very careful approach to the colours and textures of the existing materials. Every restoration project involves the incorporation of a percentage of new materials. If the aim of restoration is above all to recovery the building, this percentage should be discreet in its presence and as low as is compatible with real requirements. This compatibility can be achieved by means of a careful choice of materials (timber, aggregate, the impasto of ceramics, etc.) and the texture of their surfaces, as smooth finishes and mechanically produced materials in a traditional building do not sit easily beside pre-existing elements. This calls for a process of reflection and choice that does not involve any extra cost.


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Installations The increasingly voluminous and invasive insertion of installations can produce a great impact on traditional construction if care is not taken to ensure discreet integration. The installations required by electricity, plumbing, telecommunications, lighting, heating, etc. have become the intestines of today’s buildings, with a length and a presence that requires a great deal of space. The first step to take to ensure compatibility is to examine the various alternatives on offer in order to find the most suitable for the conditions and the character of the existing building. Subsequently there are two clear possibilities: leaving the installations partially or totally on view or concealing them as far as possible. In the first case, the choice of elegant solutions, quality materials, chromatic integration or location above the line of lighting make them more acceptable in the interior of the traditional building. In the second case, building cavity walls that

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also serve the purpose of increasing insulation, the creation of false floors, passing tubes and cables beneath shelves or kitchen units, etc., helps to conceal the installations without affecting the building’s interior. In both cases, a healthy dose of effort, reflection and imagination in collaboration with specialized installers will produce the most suitable solutions to respect the character of the building, without necessarily increasing the cost of restoration. The economics of the intervention Initial reflection and work on preliminary studies will avoid future errors in the project and on site, the need to correct a chosen course, and unnecessary rectifications, demolition and reconstruction. Ultimately, this initial reasoned approach and the preliminary study help to make financial savings on the intervention. The restoration of monumental architecture and, to 7

Section of the project to restore an old waggoners’ inn in Torrebaja (Valencia, Spain), which manages to conserves the building’s spontaneous vernacular charm and introduce all the functions required by present-day catering

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a large extent, traditional architecture requires a concerted effort of analysis and thought during the project in order to avoid greater costs during on-site work. The conservation of traditional architecture as conceived of in this article may be branded as romantic, and there could be some truth in this statement. But the conservation of traditional architecture also has a decidedly economic side, as the maintenance of the fabrics, structural floors, roof and other elements revert to optimum use of inherited resources that are simply conserved or reinforced, to the detriment of more expensive solutions such as the blanket replacement of elements. Alongside the economic aspect, there are others such as the sustainability of this form of architecture by definition, its ecological virtues and its commitment to bioconstruction, all aspects being called for by many specialists and future homeowners. 7

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Technical issues in housing rehabilitation

II. Reflection and the Project

Michel Polge Chief architect and urbanist Technical Director of the Agence Nationale de l’Habitat (ANAH), France

Rehabilitation is not simply remedying a state of dilapidation or putting something in order, it also involves improvement. Traditional construction presents various types of technical problem. Intrinsic pathologies: Damp is a recurrent problem in rehabilitation: rising damp due to capillarity. Damp is also associated with the classic infiltrations via the building’s envelope, due to excessive containment which may be linked to poorly designed insulation or inappropriate maintenance practices (sluicing of houses). In general, the porosity of old construction materials, combined with the absence of waterproofing mechanisms between construction elements, is a constant source of damp which is aggravated by insufficient ventilation. The negative consequences for the building are evident; the consequences for inhabitants are no less real, beyond that of discomfort. Deficiency in the materials: since traditional architecture is built using local resources, mediocre quality will lead to greater repair needs (stone pathologies, poorly fired bricks, etc.). Traditional attacks on timber: termites, fungal decay, capricorn beetles, etc., before timber treatments were invented, knowing that these treatments also represent problems for the environment (this is why organochlorine treatments were abandoned in France). The presence of lead paints represents a major risk of lead poisoning, particularly for children, and calls for very specific working conditions. Lead pipes also contribute to the lead poisoning problem. Other issues, such as radon gas emissions that are health hazards for the occupants (radon is a natural carcinogenic radioactive gas given off by volcanic rocks such as granite and basalt, which is a health danger for inhabitants if appropriate ventilation and insulation precautions are not taken). Pathologies due to inappropriate interventions, often linked to the use without suitable precautions of modern technical materials or procedures in an existing construction, e.g. the application of cement renderings to façades with untreated damp caused by capillary action. Then there is asbestos, a natural product that has been shown to be a real health hazard. We could also mention more classical interventions that disrupt structures: the most usual is the suppression of elements of roof structure (tie

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Beirut, Lebanon

beams, etc.) to make space in the attic, a structural ablation that suppresses the original triangulation. The installation of modern conveniences not originally catered for: bathrooms, rational heating, energy, etc. Even in those countries where rehabilitation is already an old phenomenon, this is a priority for many existing dwellings. Technical aspects linked to health issues. Some have already been listed above. Failings in indoor air quality still cause respiratory diseases, allergies, etc. Adaptation to an ageing population is a growing issue in housing, due to demographic evolution and the increase in life expectancy. This new factor introduces the issue of the reduced mobility of some occupants and, therefore, the question of accessibility to and inside dwellings. Technical aspects linked to safety. Firstly, all the accidents that occur in domestic situations in the home, of which the general public is far less aware than road accidents, because they are more “discreet”: accidents caused by electricity networks and dangerous gas, accidents caused by falls (children are frequent victims as a result of failure to envisage this risk and install guardrails), etc., which produce in the order of 400 deaths a year in France.

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As regards safety, fire is a large risk that is all too frequently seen by the population as unavoidable. However, when carried out, information and awareness campaigns about good practice do limit risks, as does the installation of simple equipment (autonomous smoke detectors), not to mention sprinklers, smoke extraction hatches, etc. This long inventory does not set out to be exhaustive. It might lead the reader to think that existing housing is so pathogenic that nothing can be done. Conversely, he might prefer misplaced optimism and decide to take no action. The question, however, is the obvious fact that as regards the technical field, the authorities’ will to improve housing, even private dwellings, cannot be limited to promoting repair work. To conclude by outlining what I consider existing housing should be in the near future, the objectives should be the following: 7

Healthy, adapted housing (with attention to issues of hygiene, comfort and access) Safe housing (with attention to questions of structural stability, safety and prevention of the principal risks) Housing that does not waste energy or resources (with attention to running costs) Housing that is designed to be sustainable (with attention to the long life of the housing product)

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Choosing the project direction

II. Reflection and the Project

JosĂŠ Luis GonzĂĄlez Moreno-Navarro Doctor of Architecture Professor of the Department of Architectural Technology I, School of Architecture of Barcelona (Technical University of Catalonia), Spain

The rehabilitation project The project is the result of the synergy of a series of decisions, each taken independently of the rest to solve a partial problem. However, since the building is unique, these partial solutions also have to constitute a simultaneous solution to all the problems. This is the greatness and the major difficulty of the architecture project: it will only be suitable if it is the result of a process based on the detailed analysis of problems and solutions that leads to a single solution that solves all of them. A project to transform existing architecture differs essentially from an architecture project for a new construction. There are particular differences in the case of a project for the rehabilitation of traditional domestic architecture. The first difference lies in the fact that, although the new construction calls for an understanding of the place and its context, intervention in something that already exists requires an understanding of something infinitely more complex: a series of construction elements that enclose and delimit spaces, which, in turn, are the result of a complex historical evolution, frequently difficult to learn (1), forming part of a sign of identity of a community and a place. This understanding means embracing intangible, symbolic aspects that are difficult to apprehend other than by patiently listening to the inhabitants of the place or to historical events that are there but very difficult to see, discriminate and explain. It also involves tangible facts such as walls (2), structural floors, vaults, joinery and flooring, and in particular an understanding of how the 20th century has transformed something that may have been constant throughout previous centuries but has been forced to change radically by the blaze of evolution of the last 100 years. Traditional housing is the product of the optimization over the centuries of a series of types associated with specific uses, producing designs that are closely adapted to the place and the lifestyle of its occupants. But with the arrival of the 20th century, the conditions of use changed radically, leading to: An increase in dead weight as the result of upward extensions or additions to the top of a building that exert added loads on the ground-floor walls (3) An increase in the number of people using the building The loss of the tradition of maintenance of elements that provide protection from atmospheric agents, such as renders that are vital to maintain the bearing capacities of walls and

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1. The building before the intervention (a) was the product of a complex historical evolution (b).

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2. Testing the façade of the building to find out its physical make-up.

3. Metal sheet reinforcement of the arch supporting a stair vault.

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rammed earth, which are very sensitive to contact with the elements (4). We are, then, analysing buildings that, in the 19th century, to take one example, might have been in a perfect state of conservation but which, by the end of the 20th century, had entered into a state of degradation due not to poor original design but to powerful changes in the conditions of use and maintenance. Understanding this is a task on its own, and these articles provide some guidelines to undertaking that task. However, it is obvious that until this understanding has been achieved, it would be immoral to embark on a project of architectural intervention.

The path to be followed Let us suppose that the architect or engineer has reached this understanding; this is a convenient moment to recall the principles with which buildings have to comply. Any element is the consequence of the need for: A space delimited by a built material form that is stable from the first moment Improvement of the environment and safety of the occupants Satisfaction, on the part of the forms and materials, of the desire for beauty that all peoples, however simple, owe to their human condition A construction that is as long lasting as possible with the aid of suitable maintenance A production method that is as efficient as possible

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A good procedure for carrying out a project is to initially follow a course that includes a study of the problem-solution relation from the viewpoint of each principle independently. Once completed, it will be necessary to evaluate possible compromises between partial solutions in order to find those that can provide a reasonable response to the problems, even if each one individually is not perfect. The repetition of the process will, finally, produce the definitive proposal. Space and structure The rehabilitation project has to be based on the fact that the space already exists. The starting point of any project for new construction—how to organize a given space according to the programme—is provided. In this case, the task is another: it is necessary first to understand the space, its reason for being and the possibility of introducing changes into it by means of minor modifications to existing elements. It is very important to remember that the space exists thanks to a series of elements usually referred to as the structure, a word that did not exist in construction terminology until the 20th century. Any important change to the space will involve structural changes. The key characteristic that differentiates these elements from their present-day counterparts is the fact that both the elements that provide stability and those that enclose space coincide, so that the structure is the outer facing or the latter is the structure. When dealing with traditional buildings, to speak of structure means almost entirely to speak of outer facings. This way of designing buildings is generally unknown to construction professionals who have trained in the 21st century, when the specialization of construction elements means that


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4. A rammed-earth wall that has lost its protective render due to lack of maintenance.

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5. Test to analyse the ground beneath the foundation of the solid brick wall.

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some provide stability and others provide protection from the exterior; it is therefore advisable to highlight this difference from the start. Furthermore, before making any decisions, it is essential to follow the process of knowledge and understanding outlined above. One of the fundamental aspects that the project needs to address is the need arising in association with many national regulations to adapt the new building to technical codes, which are always written for new constructions. This is one of the enormous difficulties that has to be addressed by the overall project, since, by definition, technical codes seek to improve the conditions of new buildings in comparison with the old, with the almost certain result that old buildings do not comply with the new levels established. The course taken has to analyse all the factors that affect the stability of these structural elements, choosing the intervention that manages at least to reduce the gap between the safety factors established by the new code. The situation is different if the regulations refer only to dead or even earthquake loads. In the first case, everything depends on the safety level imposed by present-day regulations for new constructions, which can range between 2.5 and 3. If the result of calculating the safety of an existing building is two, it might lead us to conclude that it is not safe. However, there is no point subjecting it to a difficult, aggressive process of reinforcement, since a state of balance that has existed for decades—supposing that no lesion has occurred—is proof that is at least as scientific as the application of regulations. One particular case is the consequence of carrying out geotechnical studies. Such studies frequently report that the

land on which a building has stood for 200 or 300 years is not sufficiently stable. The error may be not just the result of applying this disproportionate safety coefficient; it may also have been carried out outside the building, on a different site to that of the foundations (5). The issues change if the regulations govern seismic actions. In regions where long periods pass between serious earthquakes, their effects are not engraved on the collective memory, so builders do not include anti-seismic measures. New regulations based on precise, hitherto unknown historical and geological information, may provide clues as to the probability of a further tremor to which the building is clearly vulnerable. This is, of course, not a case of a pathology, but it is still advisable to make the most of rehabilitation to introduce the necessary reinforcement. Environment and outer facings As regards the environment, the project requires a meticulous evaluation of the performance of the envelope of the building in question in relation to the basic variables that determine the environment: firstly, those derived from the natural climate of the place—that is, rainwater or moisture from the site, heat and cold, and natural lighting; and, secondly, those deriving from our own activity, noise and pollution. The process has to consider three levels of study: the geographical, that of the building’s immediate context, and the building itself. The most important transformation generated in the 20th century came as a consequence of the increase in technology available in all fields of convenience and comfort (6). While the envelope of the building is an essential element in creating an interior

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6. Aluminium frames with thermal break and double-glazing to improve comfort levels and save energy.

7. Structural floor of glue-laminated wood calculated to provide fire stability of 90 minutes to guarantee safety while conserving the traditional image.

atmosphere that is favourable to life, our present-day civilization, of which traditional architecture has to become a part, calls for far superior environmental conditions, for which the only solution is to introduce installations of all types: water and electricity in almost all cases and heating in many. The study of energy saving (also a requisite on the part of the public administration in the form of regulations that have only recently come into existence) is an important issue, as the installations that control heating and cooling are the ones that take up most space. Recent trends point to the incorporation of cooling systems in hot places for the summer months. Likewise, the need to save energy is generating new elements outside the building as well as in its interior. The obligation for buildings to incorporate solar collection systems for domestic hot water is a recent one. It is a major challenge to see how this factor—one which we cannot relinquish—influences traditional architecture. Nor can we forget the occupant’s safety, a previously non-existent and now key aspect of which is everything to do with fire protection (7) and the necessary adaptation of buildings. We also have to control other lesser aspects such as user safety.

satisfaction of the desire for beauty that all peoples, no matter how simple, feel as part of their human condition. All the variables at play here are perceptible mainly by the sense of sight and must therefore be referred to the visual characteristics of the two constants in construction: form and material. Form is defined by its outline and by the volumes that can be perceived in the third dimension perpendicular to the observer, subject to the conditioning of the lighting. Material is defined by the visual characteristics of its surface, composed mainly of two variables: colour and texture. Further, as a result of the complexity of any construction material, we have to add the pattern drawn by the lines that separate the different colours and textures of the specific materials, and the inevitable marks of application or other actions. The decisions taken on the basis of these considerations have to be reconciled with all the previous decisions, taking care above all not to contradict the consolidated feelings of the users (8).

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Aesthetic-symbolic values Yet in isolation, none of the above is enough: all of these elements together have to create a visual message of which we feel proud and that serves to say who we are. As well as resolving all the practical problems, they have to be in keeping with our visual and symbolic culture. In short, an integral part of the building is the

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Maximum duration The passing of time takes its toll on buildings. No matter what preventive measures are taken, construction elements undergo variations in the basic characteristics of their forms and materials, and, sooner or later, cease to match their initial performance. However, the effects can be foreseen and, to a large extent, reduced. Each building is the product of its history, and this historical evolution involves factors that give rise to alterations in its initial state that may become lesions or damage. As well as being vital to correct these


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9. Corrugated sheeting under the tiles guarantees waterproofing without changing the outer appearance.

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8. Traditional stuccoing of the building’s façade.

alterations, a study of the building serves to draw conclusions and apply them to the design of new elements, ensuring that these factors of degradation are neutralized in the future. Damages may affect structural systems, with the serious consequences this may involve, but they can also affect elements whose role is to create a pleasant interior space for all the senses— the finishes. The project must explore the reasons for these damages and take an integrative approach to solving them. Experience shows that the elements that suffer most from history— that is, the passing of time—are those that are exposed to the elements, in contact with exterior space, rain, extreme temperatures, groundwater, etc. In the absence of suitable maintenance, they will inevitably deteriorate. Nor must we forget that these exterior elements play a twofold role of protecting the structural elements, such as walls or roof and vault structures, and acting as a visual support for the proposed aesthetic, symbolic and identitary values of the building. It is, then, vital for the project to analyse the factors of degradation with a view to controlling and correcting them, proposing solutions that may be more resistant, but most importantly preventing their loss and ensuring that their associated aesthetic, symbolic and identity-giving values are conserved (9). Production techniques In order to achieve the aim of durability, it is vital to ensure that the characteristics of the materials used, particularly new

materials, are compatible with the existing ones, which requires thorough verification. This will include consideration of the longterm repercussions in order to prevent undesirable secondary effects. In general, the choice between innovative and traditional techniques has to be well justified, and it seems reasonable to give preference to those that are least invasive and most compatible with existing elements, always with reference to the requisites of safety and durability (10). In theory, this automatically rules out the techniques that became habitual in the second half of the 20th century, which not only do not comply with the above aims but have been shown to be pernicious only a short time after application. Any interventions that may be planned on the basis of these criteria will of course require comprehensive knowledge of the building in question, which will involve applying the criteria of diagnosis outlined here and a thorough knowledge of today’s least aggressive techniques but also, most particularly, the traditional techniques that originally produced the building. This type of knowledge may be the hardest to acquire, as in many cases the techniques have been forgotten, as they are no longer used. This may be an insurmountable difficulty: the absence of workers such as masons and plasterers with the expertise of their fathers and grandfathers. All of these issues have to be raised at the project phase. If, for example, there is no chance of finding a mason who knows how to build a brickwork vault, it will be necessary to find an alternative solution. In short, the project has to be in keeping with

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the technical possibilities of the place. This is true of new constructions, and all the more so in the case of the rehabilitation of traditional architecture. Some final considerations Having completed this process, which gives us an understanding of both the object and the ultimate objective of intervention (to produce an artefact situated in the 21st century which serves present-day inhabitants), the next step is the architecture project. Obviously, the thought processes are not this clear-cut; the overall process of understanding the project progressively gives rise to ways of addressing it.

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10. Reinforcement of a traditional vault built with two layers of thin brick ensures the compatibility of materials.

11. Final state of the faรงade.

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This is not a bad thing, unless the ideas that emerge prior to a full understanding become so firmly rooted that they are maintained despite contradicting the conclusions of the process of comprehension. This is an easy trap to fall into. Prior ideas in architecture are valid provided they are compared and contrasted during the process of understanding the building; they will, in turn, be factors that serve to incentivize further research. To conclude, the project must meet the objectives of adaptation to the space, adaptation to the environment and conservation of the integrity of the building, using the economic and technical resources available, to produce a result that is satisfactory for the occupants and for the collective as a whole, satisfying the desire for beauty and affirmation of their identity (11).


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The innovation value for quality in the traditional architecture rehabilitation

Ensuring the “continuity of life” of the historical building heritage through an “appropriate use” is the basic objective for a conservation that can be considered, beyond the concept of simple preservation, as a dynamic action of future construction, in terms of “integrated conservation”1 within the social, economical and cultural realities of the territory. This issue is particularly important for the traditional architecture of the Mediterranean area, as the attribution of new functions, or even the simple preservation of the original ones, can involve the alteration of the formal, technical, material and functional values. Buildings designed for specific uses could not meet the changed requirements, connected to the functional destinations which standards have inevitably evolved over the time. Even the apparently simple conservation of the residential destination, that is predominant within the historical centres, may lead to these contradictions. In fact, the practice has demonstrated, on the one hand, that the critical states for the functional efficiency are not present only when the new destination involves structural, functional and equipment transformations and, on the other hand, that the continuity of the residential destination could allow the conservation of the original features of the building, as this destination is based on activities that change little and/or involve a very flexible behaviour. Besides, the quality of the life at one time required spaces and functions, absolutely unsuitable with the quality now imposed by the modern needs. Furthermore, the interventions of functional suitability of the building heritage have often produced, especially within the historical centres, an “adaptation” with forced alterations and introductions of elements and characters, that have changed the original typological and morphological aspects, with a dramatic difference compared to the theoretical assumption. The definition of theoretical, technical and technological tools is an important challenge in order to deal correctly with the issues of both the reuse and the continuity of use for the traditional architecture. It should avoid the transfer of adapted methods or the slavish application of functional and/or technological solutions that have been already experimented for new buildings. For this purpose, the innovation of approaches and technological solutions can be, far away from a claimed modernity in itself, an essential instrument to face the difficult connection between the conservation of the architectural and morphological values of the ancient buildings with the modern life requirements and the conformity with laws and standards in force, as well as with the demand of more and more specific and complex performance levels.

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Fabio Fatiguso PhD engineer Assistant professor in Building Refurbishment (Technical University of Bari), Italy Collaborators: research group work (Giambattista De Tommasi, Mariella De Fino and Albina Scioti)

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The “Sassi” of Matera

The wide hypogeum of the Sassi

Quality and rules within the rehabilitation of the traditional architecture Generally, within the countries of the Mediterranean area, the minimum level of quality for a building is defined, through a system of parameters/standards, by some dispositions that generally refer to “new” constructions, without any specific attention to the existing, historical and more recent, building. Besides, for the traditional and historical architecture, the common “philosophy” of the prescribing building regulations

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aims to quality control through the imposition of bonds and limitations for the practical procedures, so that a good result, also in relation with the technical and formal issues, has not been always achieved. A general insufficiency of the dispositions has been demonstrated by different studies2, as the environmental qualities have been determinate by generic advices and limitative impositions of numerical parameters, sometimes even conflicting, without any attention to the peculiarity of the intervention or the territory, any explanation of the reasons for the imposed limit and any alternative solutions to meet the required needs3. Clearly, the peculiarity of the Mediterranean traditional architecture makes difficult, sometimes inappropriate, the translation of the building quality into objective parameters and standards: the apodictic expectation to meet automatically the requirements through the observance of the dispositions is absolutely inadequate. These models avoid the rehabilitation intervention, in terms of both “simple” maintenance and refurbishment, or make its result unconnected with the structural, typological, functional and technological features of the artefacts. Even if in relation to the different territorial contexts and, as a consequence, to the specific spatial, material, technical and technological features, the morphology of the building fabric, the typologies and the particular dimensions of the primary architectural units, both in plan and in facade, and the constructive characteristics are an obstacle for the strict observance of the contemporary quantitative and numerical standards, imposed by the prescribing models. Indeed, irregular spaces with over/under dimensioned surfaces are present –from the simple rural one-two rooms North Africa dwellings and the

elementary houses in the ancient centre of Bodrum until the wide hypogeum of the Sassi in Matera; extremely variable internal heights can be surveyed –from the small earth structures within the Algerian area until the tall ceilings in Rashied in Egypt, since the low rural compact Portuguese constructions until the elevate landings of several Italian and Provencal historical centres–; very low vault impost quotes feature the traditional spaces in Matmata and Medenine in Tunis and the terraced and “tower” houses in many historical centres of the South Italy, as well as wooden floors (widely spread out in the Mediterranean area) that avoid a correct spatial articulation. Moreover, the vertical connections are sometimes difficult to realise because the landing heights are too high for comfortable staircases which would result too long. Also the ventilation and lighting conditions are frequently inadequate and do not correspond to the requirements, for the absence of suitable windows, as in many countries of the East and South Mediterranean sea, where the reduction of the openings outside was traditionally imposed by the protection from the weather conditions and the safety. Even when the windows are sufficiently large, they don’t often allow a good lighting because of the closeness with the facing buildings (let’s think to the historical centres in Apulia Region). Another issue is connected with the accessibility for people with disabilities, within the single building and the whole urban context. A survey referred to the historical centres of some Italian communes with a prevalent traditional serial building of the Middle Age4 has shown that, with reference to the dispositions in force, the 30% of rooms has not the geometrical and dimensional characteristics to be considered as habitable, the 40% of spaces is not well ventilated and lighted, the 100% of houses has not an adequate staircase. Similar results

Traditional earth structures in Aurés (Algeria)

Traditional architecture in Matmata (Tunis)

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could be probably achieved for other Mediterranean areas, because of the homogeneity of the morphological features.

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Innovative approaches for the recover of quality To overcome the prescribing approach is a necessary aim to achieve the quality, since a quality level, not meeting the modern requirements, for a part of the city with an important extension and an emblematic value is not acceptable, also considering all the social, economic and cultural implications. As a consequence, methods and procedures have to be defined for the refurbishment of the traditional historical building (particularly with residential destination) to respect the environmental and functional qualities required by the “contemporary life” and the dispositions in force. The objective may be the definition of performance values that the architecture has to show in order to meet specific requirements and the assessment of technological and functional solutions aimed to their satisfaction. The performance guide model to guarantee the quality within the building refurbishment process seems to be fitted, as it allows to set quality standards that are comparable with those ones concerning new constructions and to preserve the historical, architectural and morphological features of the existing building heritage. As a result, it prevents from applying prescribing bonds that are used to be disregarded, interpreted case by case or derogated. Concerning this, over the last years, in Italy, several studies and researches have been developed to revise the management tools for the transformations of territory and cities in terms of performances. Important experiences in this field are just related to the conservation and requalification of historical centres and/or

traditional architectural spaces, where methodologies and procedures have been often referred to the peculiarity of the territorial building context, by innovative practice instruments, such as the Laboratories of Quarter5, the Refurbishment Handbooks and the Practice Codes6. For instance, the Laboratories of Quarter were significant experiences aimed to find new ways for making easier all the choices concerning the physical, economic and social requalification of important parts of the city. All the experiences shared the institution of a “centre” where all the decisions, concerning both the management and the technical-technological aspects, were taken by the participation of citizens, administrations and firms. The Refurbishment Handbook are able to manage the urban and building quality with both prescription and guide actions, in three way: a binding one, by pointing out the materials and construction elements that cannot be lost during the transformation works, even if they are hidden ante operam; a prescriptive one, by indicating the materials and techniques that have to be used during the project, if there are not contraindications; an indicative one, by illustrating through some exemplifications the criteria and methods, that have to be considered by the designers for the project. A recent research on this topic7 points out a particular methodological approach, namely a prescription-performance practice tool that allows, by means of more flexibility and less impositions, to profit by the potentialities of the exiting traditional building and so to recover the environmental and geometrictypological values for an integrated and comprehensive conservation of buildings. This model is composed of performance specifications8, namely guide and check elements for the performance achievement. They are correlated with suitable

Traditional architecture in Médenine (Tunis)

“Tower” houses in Molfetta (Italy)

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solutions9, that are particular spatial and technological solutions not based on values describing some demand parameters, but meeting the requirements-goals consistent with the building. Afterwards, the performance approaches for the refurbishment of the traditional historical architecture offer sufficient discretion, in relation with the peculiar features of the buildings subjected to the reuse, and freedom about the valuable applications for the achievement of the expected quality result. They are based upon a process at progressive stages, since the definition of a “system of uses” – a set of the technical and technological choices coming from the demand scheme and the performance aims - and a “system of values” – a set of the bonds to the transformation imposed by the architecture to preserve its own identity - until the definition of adequate criteria and methods, through a congruence control to ensure a contemporary building quality of use and a conservation of the historical nature of the traditional building heritage. Afterwards, the operative ways to meet the pointed out requirements, sometimes explained with suitable solutions, can be referred to both “traditional methods” and “modern use” of historical materials, techniques and structural elements as well as to innovative technological approaches, through the integration between construction tradition and innovation. The table 1 shows a possible scheme of a performance approach for the refurbishment of the historical traditional architecture. The technological innovation for the quality In accordance with the experiences over the last decades, the employment of “traditional methods and materials” within the refurbishment of the traditional architecture can be considered as appropriate on the whole, with a valuable congruence between the system of uses due to the requirement reference and the

Reinforcements of vaults by FRP

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historical, architectural and technical system of values. Therefore, the “technical quality” of intervention, referred to both the functional aspects (from the environmental comfort to the technological equipment) and the architectural-formal, material, static-structural leads to a “proper quality” of all the involved choices and the solutions – the proposition of materials and technologies featuring the existing building is obviously suitable – and to a “relation quality” – the building may keep the formal, technical and structural frame and so a substantial homogeneity. This is valuable beyond any philosophical-cultural evaluation about the efficacy of the chosen approach for the conservation of the historical-architectural system of values. The above mentioned issues, coming from the contemporary debate on the refurbishment of the historical architecture, explain the wide use of traditional techniques, in contrast with the employment of modern materials and technologies that have been widely and uncritically adopted, over the recent and remote past, without an adequate preliminary control in depth upon the induced effects. On the other hand, this evidence hasn’t to obstruct the innovation within the building refurbishment. A new balance between space, preserved materials and new functional and technological elements has to be achieved that is a preservation tool, rather than a futile need of modernity, in order to link the tradition (when it cannot meet specific requirements) and the contemporary world. The main goal is not the transformation of the building, but the connection between the performance requirements and the conservation of its authenticity and original structural language, through the employment of evolved products and systems that are able to face appropriately the lack of performance of buildings that are realised with traditional techniques, but cannot be recovered with them. This approach may not concern a useless


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Logic scheme of a possible performance approach for the refurbishment of the historical traditional architecture.

and counterproductive rule, but a choice capability for those situations where the employment of modern materials and technologies may be more suitable in order to respect the comprehensive building characteristics: sometimes and for specific problems, the historical architecture seems to “accept” better the insertion of “light” technologies, for instance the more advanced ones (aimed to integrate rather than to replace), rather than “heavy” interventions, traditionally applied to the building practice over the last decades and connected to methods and techniques of substitution and reconstruction. However, the innovation is not only be related to materials and

systems, with high technological content and morphologicaltechnological compatibility, that are able to perform good durability, mechanical resistance, aptitude to maintenance and to integrate with traditional materials, elements and techniques. It also concerns the adaptation and improvement of the performance and quality characteristics related to the traditional existing products, widely experimented within the building sector. For instance, the Fiber Reinforced Polymers (FRP) have been employed to have the existing building comply with the new safety standards and the unexpected stresses, as those ones produced by an earthquake, even if a great care is necessary,

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Scheme of lighting system based on the fibre optic technology

Solar collector panel

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because the experimentations are very limited and the calculation and analysis models are not completely set, especially for the reinforcement of masonries, where the employment of composite materials is quite recent. The FRP show many advantages. They use small quantity of material, in terms of thickness and weight. They are removable and easy to apply. They don’t change the original behaviour of the structures, as they work after the tensile resistance of the element has been exceeded. Beyond the general operative modalities, a wide range of applications can be foreseen for the reinforcement of arches and vaults (in order to let these structures withstand tensile strains as they are subjected to combined compressive and bending stress) or for the bandaging of masonries or single building elements (in order to avoid the damage produced by lacking connections between walls). The above mentioned issues underline that the FRP for the structural reinforcement may be more effective and less intrusive for the conservation of the material and architectural features than other materials and technologies, apparently more connected with the construction tradition. The resolution of problems related to the indoor lighting when the building arrangement obstructs the access of natural light is another example where innovative approaches and procedures are more effective than traditional methods within the conservation of the historical architecture. In fact, the most traditional solution, namely the transformation of the existing openings and/or the realisation of new ones, is also the least suitable because of the historical and architectural bonds. On the contrary, the employment of light integration systems, for instance those ones based on picking up and transferring the natural light flow, may offer more interesting solutions: from the light chimneys, traditional solutions that are architecturally congruent, until the highly innovative light carriers10, that are able to pick up and transport the solar light into the rooms with internally reflective pipes. Fibber optic systems may also allow interesting innovative solutions and future developments to carry the natural light into the building11. The natural lighting system based on the fibre optic technology is able to provide the environment with a kind of lighting at the same spectrum of the natural light. The produced lighting is directly dependent by the external one and its intensity changes by changing the external one as well. So it follows the natural cycle12. With reference to the previous examples, a choice between traditional methods and innovative solutions is still possible. On the contrary, in case of technological equipment of the historical architecture, in terms of fixtures and fittings not previously set, the same possibility doesn’t exist. So, within this field, the innovation is related to more advanced systems and products able to face the technological complexity to provide the building with adequate safety and comfort standards, by means of the integration among the technological networks and the conservation of the


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architecture and material structure. In this case, the innovation may support the well known methodological approaches aimed to minimize the “disturb” induced by the technological devices, particularly within the diffuse historical architecture where the attention to the original artefacts is lower than to the monumental buildings. The diffusion of automation systems seems to offer interesting perspectives. For instance, new transmission systems of information, data and control can reduce the necessary canalizations and the relative masonry works. The Bus systems are an example that accomplishes multiple tasks related to the energy management and control for contemporary residential and tertiary functions. Instead of independent and diversified technological devices, the new system uses a signal line (BUS), in order to exchange information and to supply the energy. This signal line is composed of a cable which all the system devices are connected to in parallel. The directed waves systems are also effective signal transmission methods (transmission at high frequency by existing carriers belonging to the electric installation), as well as the wireless systems (transmission by radio waves or infrared rays) that allow an “intelligent” management of the building and an intercommunication network arrangement among several systems without any sort of wiring13.

References AA.VV., 2002, Costruire sostenibile l’Europa, ed. Alinea, Firenze AA.VV., 2001, Costruire sostenibile il Mediterraneo, ed. Alinea, Firenze AA.VV., 1994, Abitazione, riuso e qualità della progettazione: studio di un caso. Elementi per l’analisi esigenziale-prestazionale nel riuso conservativo edilizio, Ed. Edipuglia, Bari. BLUM A., 2002, HQE2R Susteinable Renovation of Buildings for Susteinable Neighbourhood, SB02 Conference, 23-25 September 2002 CATERINA G., 1997, Gestire la qualità del recupero edilizio urbano, Ed. Maggioli, Rimini. CROCI G., 1998, The conservation and structural restoration of architectural heritage, Computational Mechanics publications, copyr. Southampton DE MATTEIS L., 2003, Recupero edilizio e qualità del progetto, Primalpe, Cuneo. DE TOMMASI G., 2001, Qualità prestazionali per il recupero dell’edilizia storica seriale. Un approccio metodologico per un codice di pratica, Adda editore, Bari FOSTER L., 1997, Acces to the Historic Environment, Donhead, Shaftesbury. GERMANÀ M. L., 1995, La qualita’ del recupero edilizio, ed. Alinea, Firenze. HARRIS, S. Y., 2001, Building pathology: deterioration, diagnostics and intervention, IMPERADORI M., 2001, Costruire sul costruito : tecnologie leggere nel recupero edilizio, Carocci Roma MECKLER, M., 1996, Improving indoor air quality through design, operation and maintenance, Fairmont London Prentice-Hall Int., Lilburn, GA, MONTAGNA, R. (a cura di), 1999, Normative edilizie e forme del costruito, ed. CLUA, Ancona. RABUN S. J., 2000, Structural Analysis of Historic Buildings: Restoration, Preservation,

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and Adaptive Reuse Applications for Architects and Engineers, Wiley WATT, D. S., 1999, Building pathology: principles and practice, Blackwell Publishing.

1

The integrated conservation can be defined as the result of the combined action between restoration techniques and research of appropriate functions (ICOMOS, Amsterdam Declaration, 1975).

2

Montagna R., The effectiveness of building dispositions for the safeguard of formal quality for the built environment (in Italian L’efficacia della normativa edilizia ai fini della tutela della qualità formale del costruito), in Edilizia Popolare n.250 4-5/97, Rome; De Tommasi G., Fatiguso F., Napoli F., Fulfilment of building standards in the refurbishment of historical housing. General issues and conform examples – in Proceedings of 10th International Scientific Conference “Integrated Protection of the Built Heritage – Tusnad 2001”, Tusnad 6-12/05/2001, Transylvanian Monument Restorers Society.

3 For instance, in Italy a room is habitable if seven standards (Surface, Dimensional Ratio in Plan, Height, Volume, Internal Quote from the Street, Ventilation, and Lighting) are satisfied that have been exclusively expressed by absolute numerical variables. 4 The survey has been carried on some communes in the province of Bari, in Apulia, where the basic building type is composed of elementary cells, arranged as “tower houses”, developed on different floors with separated accesses and connected in two opposite series to shape “double comb” blocks. 5 The Laboratories of Quarter of Otranto, Bari, Rome and Cosenza lasted from 1981 until 1995. The pilot experiences of the Laboratories of Historical centres were equally interesting that were instituted by Sardinia Region in order to activate management and preservation tools for all the several small traditional historical settlements widespread over the territory. 6 Among the Refurbishment Handbook, the first is the “Restoration Reference Book” in 1977 within the Laboratory of the Associazione Intercomunale Pescarese.; then, the “Refurbishment Handbook of Rome” in 1989, the “Refurbishment Handbook of Città di Castello” in 1992, the “Refurbishment Handbook of Neapolitan construction traditional techniques” in 1994, the “Refurbishment Handbook of Palermo” in 1994; finally, the handbooks referred to Matera, Ortigia, Umbria and other ones. We highlight the “Catalogue of Typologies and Architectural Elements” of Umbria Region that with the “Model of Building Regulation for Refurbishment” constitutes the basic reference for the urban and building requalification of historical areas in Umbria Region. 7 G. De Tommasi, Performance qualities for the refurbishment of the historical serial building. A methodological approach for a practice code (in Italian Qualità prestazionali per il recupero dell’edilizia storica seriale. Un approccio metodologico per un codice di pratica), Adda Editore, Bari, 2001 8 The performance specifications are the operative contents of the model and contain the basic concepts to meet the considered requirements. Their structure is composed of a description-performance proposition and a procedure scheme: the former expresses the performance quality goal, the lower limit values of numerical parameters that involve the requirement meeting, the criteria to verify the performance quality when to respect the pointed out standards is impossible; the latter, arranged in a block diagram, allows, since the control of one or more demand parameters, to check the possible achievement of the performance quality, by means of both the satisfaction of the pointed out prescription and alternative ways chosen by the designer. 9 A suitable solution is a solution not necessary copied by the proposed model, but that meets the basic features and give equivalent performance values, even if with some differences from the model. 10 Beyond commercial solutions (Solatube Systems), an interesting research, namely ARTHELIO (Intelligent and energy-optimized lighting system based on the combination of daylight and the artificial light of sulphur lampos (JOR3-CT97-

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0177) Joule II_RES Non-Nuclear Energy Programme) focused upon an innovative picking up, carriage and diffusion system of the natural light combined with the artificial one. Mingozzi A., Bottiglioni S., Indoor Lighting with natural light carriers (in Italian Illuminamento di ambienti interni mediante condotti di luce naturale), in Lucchini A., The innovative roofs, (in Italian Le coperture innovative) ed. Il Sole 24 ore, Milano 2000; Bottiglioni S., Innovative systems for the natural light picking up and carriage: the European Project “Arthelio”, in AA.VV., Sustainable Construction the Europe, ed. Alinea, Firenze 2002. 11 The natural lighting system based on the fibre optics technology has been studied and experimented within the projects SPECTRUM and “The Sunflowers”. SPECTRUM Solar Power Exploitation by Collecting end Transportation by fibre optic to Remote Utilisation Modules - Joule European Project (J0R3 CT97 – 0188 C) is a research programme by CEO in Florence; “The Sunflowers” is an Italian programme by CEO. F. Francini and alii, Solar system for the exploitation of the whole collected energy in Press on Optics and Laser in Engineering 39/2 233-246 (2003).

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12 The light picked up from a manifold and carried by the fibre cab be spread over the environment, for instance, by means of an “artificial window” (a translucent glass diffuser surface located close to the real window as a natural enlargement) or some terminal elements on the ceiling; both the systems can also be employed in an additional way, in order to optimize the natural lighting of the space. 13 A real application of technological integration and automation principles has been realized within the refurbishment of the abandoned village of Colletta di Castelbianco (Italy), transformed by architect Giancarlo De Carlo into a “telematics town”.

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Notes on the rehabilitation and reuse of traditional and historical architectural heritage

Reuse in architecture is a historically widespread practice directed at built objects which, despite no longer responding to the original demands for which they were constructed, still allow (subject to processes of modification) adaptation to new functions. In general, the concept of reuse is associated with a long-term interpretation of the architecture. The life of a building tends to be marked by periodic episodes of modification (simple repairs, extensions or partial demolitions, changes of use, review of function, etc.) that reflect changes in society and its demands. These modifications go to define the historical course of buildings, but they can also be regarded as critical moments that put the applicability of a fabric to the test— that is, they verify its capacity for adaptation and, implicitly, of duration. The test of time will be too much for buildings with a closed approach that does not respond to new expectations—that is, buildings that remain static or inert in the face of changes to their conditions of use. Furthermore, there is no disputing the fact that “the older a building is, the more likely that its original structure is no longer intact and that its initial function will give way to others”1, and this is valid for both anonymous, current buildings and their historical and artistic counterparts. The latter, with their indisputable historical and artistic value are characterized by a meaning and recognizability associated with a specific function in the collective memory (one example, though not the only one, is the case of religious buildings). By way of example, many Roman amphitheatres in Italy, Spain or France were absorbed in the Middle Ages into the urban fabric of walled towns and transformed into habitable organisms and Michelangelo transformed the thermae of Diocletian in Rome into the basilica of Santa Maria degli Angeli, not forgetting the endless series of extensions to the Mosque in Cordoba, ending with the conversion of the Islamic mosque into a Catholic church by the Spanish architect Hernán Ruiz the Elder in the early 16th century. These are just the best-known cases in the history of architecture. The continuity between the sequence of changes and the original act of construction or, to put it another way, the conservation of the building’s own identity, according to Moneo, is possible thanks to the permanence “of the disciplinary principles established by the architect at the moment of construction” and is unaffected by modifications to the actual building, provided these principles are “sufficiently solid”2 and valid. It is interesting to note that this consideration is still valid if we replace the word architect, historically representing the idea of highbrow architecture, with the word builder, referring to built rather than designed historical-

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Carlo Atzeni Civil Engineer Professor in the Department of Architecture of the University of Cagliari, Italy

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Serrenti, rehabilitation and reuse of Corda House as an arts centre and municipal library (project: Antonello Sanan and Alessio Bellu)

traditional architecture. Permanence and modification are, then, complementary rather than opposing concepts. Modification inevitably follows construction and may in some cases involve traumatic consequences, but the identity of a work with personality and character will in the long term be reinforced rather than questioned. Consequently, the practice of transformation forms an integral part of the evolutionary process of all architecture and is possible only by means of recognition and respect for the original nature of the fabric, because “architecture that is clearly defined will always be open to new interventions that indefinitely extend the life of a building”3. Modification is, then, the most valid instrument for ensuring its permanence. Nonetheless, reuse presupposes a cessation in the continuity of use of the building4, an interruption in the activities carried out,

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awaiting a possible new fate. Rather than a reductive interpretation as “[...] a simple change of use”5, reuse can be seen as the bridge that re-establishes continuity between the past and present of the existing building. Conceptually, modification constitutes the essence of reuse, as indeed it “involves a transformation, a veritable metamorphosis of the existing. The presence and absence of continuity do not simply go together, they actual form an indivisible relation”6. In the life of a building, its reuse coincides with a crisis of loss of the values that hitherto underpinned its meaning and existence. Reuse involves assigning the existing construction a new system of values and meanings, different to what went before, which is why this is not always possible7. Reuse must, then, be seen as a dynamic instrument by means of which the pluralities of past and, most probably, future successive uses become stratified, intersect and establish a rapport8, not simply as a change in function. The building boom that hit Italy in the late 1950s, along with the need for post-war reconstruction, population growth, the industrial development of cities and the resulting phenomena of migration to them, decreed the depreciation of existing built heritage. The idea that had until then governed the ongoing logics of maintenance, repair and reuse of pre-modern architecture, was supplanted by the economic reasoning behind new constructions, mainly associated with industrialized technology and the mass production of construction materials and elements. At the time, it was probably more convenient to build new constructions than to conserve and reuse old buildings, due to the rapid disappearance of the professionals who conserved the technological and building expertise of traditional practice. The passage from the second to the third millennium has seen many changes in the conditions that most directly influence the relation between space and society; this is a period in which population growth is undergoing a reverse trend, with zero birth rates. The buildings constructed in the last 40 years have aged suddenly, unexpectedly and probably to a larger extent than traditional constructions. Today, large and medium-sized city centres are coming up against a sadly chronic lack of development land and, as a result, the displacement of inhabitants towards the centre—giving rise to a new distribution from old towns to city outskirts—seems irremediably blocked or, perhaps, about to be reversed. In short, the phase of unbridled expansion that cities experienced in the second half of the 20th century seems to be set to undergo a radical inflection: the city, in a wealthy, ageing society, seeks within itself new—or old?—places in which to live, and quality in the installations far outweighs quantity. All this, along with communities’ manifest need to discover and re-appropriate their cultural roots, generates interest in the built historical fabric. From this viewpoint, the recovery-reuse binomial once again becomes the operative instrument of a cultural model which, to

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paraphrase Magnano Lampugnani, could be defined as the model of maintenance and continuity, as opposed to a more ephemeral, short-lived model such as the case of replacement9. Now, the rehabilitation project constitutes an act of foresight, reading and interpreting the main characteristics of the existing to plan its potential for reuse in the near future. The motivations behind rehabilitating buildings are, firstly, of an economic nature, which might be summarized thus: “[...] since it was not possible to construct new buildings, work was carried out on the existing structures”10, though in keeping with Riegl’s definition of the unintentional monument “[...] we must not forget that history, for at least 50 years, has valued them as sources of material testimony, especially if they are many and widespread.” Therefore, “suppressing a building or a part of it amounts to erasing a page in the life of society that has been passed down by the material itself”11. And this is even more valid in the case of popular architecture; despite as a rule having no design documents, it recounts its history, from the twofold viewpoint of continuity and mutation, by means of the built work itself. Indeed, “[...] it is necessary to see spaces and their subsequent transformations as a precious, irreplaceable book which, by means of materials and the configuration given to them by the people who lived there, tells of the change in use and social balance more effectively even than a drawing, and justifies the choice of continuing to inhabit these spaces and the decision to conserve them”12. The historical period in which we live is going through a moment of reflection on the choices made and possible new paths, and is characterized by an increasing exhaustion of resources. This

Gonnosnò, rehabilitation and reuse of a traditional house as a House Museum (project: Maurizio Manias and Franceschino Serra)


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requires us to place the issue of saving, in the broadest sense, at the centre of debate and research, bearing in mind that “[...] producing to consume and then throw away means waste. And waste is precisely what we cannot afford in a world affected by mountains of waste products and worried about its limited resources”13. These are just some of the substantial reasons pushing us towards a definitive awareness that our existing built heritage is of great cultural value. It is, however, without the slightest doubt, an economic resource, an important added value, which at present we are allowing to fall into disrepair and have to revalorize as soon as possible. Conversely, the terms of the urgency of the reuse of a building can be inverted, as Corboz provocatively posits, in which case “[...] it is necessary to declare the need to destroy rather than the need to conserve [...]”14. The rehabilitation project, potentially part of the rich vein of the built project, has to address a plural system of links, since it addresses a built organism that is there to be reused. On the one hand, for the project, the building is a physical, material place in terms of its architecture and construction and a virtual place by virtue of its historical, evocative dimension. At the same time, the new use presents demands that are linked to the restructuring of the building. A good rehabilitation project, then, has to be able to choose suitable new functions for old buildings that are compatible with their original essence. The equation that simply balances the reuse of the old building with the new function is meaningless, as it expresses something that is impossible. “In the face of the continual destruction of resources and memories that is erasing a

Albagiara, historical traditional house set in an urban revitalization programme, before its rehabilitation

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little more of our cities every day, the foremost parameter in the evaluation of a project has to be its ability to respect and use existing resources”15. Modification as a result of reuse of existing buildings, and particularly of the project in consolidated areas, though not necessarily reuse in the strict sense, once again sets forth the dualism between old and new, especially due to the technological progress that is now radically changing the languages of architecture. In these cases, the critical act of the project necessarily has dialectical contents: the new has to affirm its own project identity without prejudice to the pre-existing. The project mandate is to establish a nexus between old and new. The relation should not be one of antagonism, because “[...] the project is constructed with different parts, some that are by necessity new and others that existed beforehand. Bringing the two together will not involve a unitary composition; it will be an attempt to achieve a level of quality analogous to what existed before”16. That which is already present will guide the course of modification when these levels are defined, to then extract the vital lymph. In other words, the designer has the difficult task of understanding the complexity of the old building and then defining the modifications accordingly. In his interesting essay Del contraste a la analogía, Ignasi de SolàMorales further clarifies the connection between old and new in the recovery project, indicating that “[...] a new architecture is physically close and relates visually and spatially to the existing, but it also establishes a real interpretation of the historical material. This material, of which the architecture is comprised, becomes the object of a veritable interpretation that, explicitly or implicitly, accompanies the new intervention in its overall significance”17. Analogy and contrast or “similarity and difference”18, to use wellknown binomials, are ultimately the ciphers of the recovery project in which tradition and innovation come together and are stratified. The cognitive approach—the diagnosis project— referred to above is a vital preliminary instrument to undertaking this comparison. It reduces the random component without actually eliminating it19, and is unable to deterministically codify the actions of the design phase. Since each case insists on its own individual dignity and the very plurality of cases generates the complexity of urban systems, this complexity cannot be extended to methodological generalizations and simplifications derived exclusively from typology. It must be said, however, that typological taxonomy, if correctly used—and this will depend on the choice of the parameters of evaluation—can be an important instrument of support to the project in defining the criteria of interpretation and comprehension of its own complexity. We are aware of the difficulty today of referring to a theory of

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rehabilitation or of more general comparison between existing and new that is univocally accepted. It is, nonetheless, necessary to assume that the contemporary project culture has for some time now addressed the existing in the joint form of conservation and modification, allowing the principles of the restoration discipline to coexist with the need for autonomy required by the architecture project20. Without relinquishing the charm of ambiguity in the contrast between the old and the new, it is possible to substitute for “the habitual trio of restoration, reuse, conservation, a more up-to-date, judicious approach: restoration, reuse, transformation”21. Homogenous methodological instruments are lacking, but it is still possible to compare certain operative criteria. One such is the “principle of minimum intervention”22, which represents the principal link regulating the rehabilitation project and reuse, with an approach inspired by cultural stances on the conservation of the historical document. According to this principle, pre-existing elements should only be modified if it is necessary to the new function. From a technical and material viewpoint, this means addressing problems of degradation by means of the priority choice of conservation rather than gratuitous substitution. Another element in defence of the unique, unrepeatable nature of each existing building, in its historical and material dimension, is the “principle of reversibility of interventions”23. According to this principle, the rehabilitation-reuse project must not be regarded as definitive; it should, rather, adopt a stance that leaves the way open to reflection on the choices made and enable the removal of what has been added without denaturing or irremediably damaging the original building. In this light, the issue of compatibility acquires a decisive role. It must be approached at two different scales. The first, as explained above, refers to the bonds that the old building imposes on the choice of the new function or, to invert the terms of the question, the degree of modification that the change imposes on the existing building. This ultimately means considering the level of analogy between the demands manifested by the preceding and following functions. The second is more directly associated with implementation, but is nonetheless important. It concerns the possibility of using present-day materials and techniques in the historical fabric. The requirement of reversibility and the difficulty of ensuring that techniques and materials from different time periods coexist harmoniously go hand in hand and suggest the advisability of “systematizing in a building only lightweight and removable elements, whose points of anchorage are independent of the structure into which they are introduced [...]. It is not advisable to try and conceal the means of adaptation; they introduce a refreshing tension, preferable by far to the habitual cunning which consists in trying to convince observers that the

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intervention is not contemporary”24. This process preserves the recognizability of the intervention desired by the restorers, though with different budgets and purposes, and is, ultimately, one of the basic requirements for the success of the dialectic project referred to25. The middle way between conservation and modification represents the leading thread of the rehabilitation project, which has the mandate of establishing the degree of prevalence of either approach. This serves to free up rehabilitation from historical

Albagiara, floor plan, sections and elevations of the project for rehabilitation and reuse of a historical traditional house as a rural culture documentation centre for the region of La Marmilla (project: Carlo Atzeni, Maurizio Manias and Silvia Mocci)


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disciplinary prejudices that do not admit of its propositive value and accept technology as one of its principal conceptual and operative instruments.

1

André Corboz, “Vecchi edifici per nuove funzioni”, in Lotus International, no.13, p. 76.

2 Rafael Moneo, “La vita degli edifici e la moschea di Cordoba”, in La solitudine degli edifici e altri scritti - Questioni intorno all’architettura. Allemandi. TurinLondon, 1999, p. 132. 3 Rafael Moneo, Op. cit., p. 155. 4

“[...] reuse [...] implicitly means the existence of interruption to continuity—an interruption in use. In fact, when an intervention of reuse takes place, it is the continuity of use that is lost, manifesting an irremediable interruption. If it were to continue, there would be nothing to reuse, because reuse, in a context of continuity, is, quite simply, use [...].” Marco Biraghi, “La via del riuso”, in Casabella, no. 672, p. 15.

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meaning of the historical architecture or the intentions of the new intervention.” Ignasi de Solà-Morales, “Dal contrasto all’analogia. Trasformazioni nella concezione dell’intervento architettonico”, in Lotus International, no. 46, p. 37. 8

“In the buildings of the past that are subjected to constant variations of use, the old and the new combine. Original, almost intact constructions, preserved for reasons of economy or out of respect, are found set in more recent buildings; exposed or concealed beneath its rendering; or perhaps just fragments show of architectural forms modelled by the superposition of functions and meanings in new uses. When the system of relations that generates the architectural form breaks down, the latter, testifying to the autonomous, unpredictable nature of its lifetime, may conserve fragments of the original meaning or, rather, generate new ones.” Alberto Ferlenga, “Separazioni”, in Casabella, no. 717-718.

9 “Insisting on the dimension of durability in the project means imposing a series of

conditions on its suppositions, methods and results. It means above all choosing between two antithetical models of production: the replacement model and the maintenance model [...] Proposing a lasting project evidently means choosing the latter [...].” Vittorio Magnago Lampugnani, “Ricambio or manutenzione?”, in Lotus International, no. 46. 10 André Corboz, Op. cit., p. 68. 11 Alberto Grimoldi, “Architettura come riparazione, Note sul restauro in architettura”, in Lotus International, no. 46, p. 118.

5 Marco Biraghi, Op. cit., p. 15.

12 Alberto Grimoldi, Op. cit., p. 118.

6 Marco Biraghi, Op. cit., p. 15.

13 Vittorio Magnano Lampugnani, Op. cit.

7 “The relation between new architecture and existing architecture is a phenomenon that changes according to the cultural values attributed to the

14 André Corboz, Op. cit., p. 72. 15 Alberto Grimoldi, Op. cit., p. 118.

Albagiara, view of the project of rehabilitation and reuse of a historical traditional house as a rural culture documentation centre for the region of La Marmilla (project: Carlo Atzeni, Maurizio Manias and Silvia Mocci)

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16 Alberto Grimoldi, Op. cit., p.120. 17 Ignasi de Solà-Morales, Op. cit., p. 37. 18

Ignasi de Solà-Morales, Op. cit., p. 44. “Somiglianza e differenza. La trasformazione dei mulini di Murcia di Juan Navarro Baldeweg” is the title of an essay by Luca Ortelli published in Lotus International, no. 59.

19 In the opinion of Ignasi de Solà-Morales, “instrumental knowledge of the object does not remove the risk element from the project […]”, Op. cit., p. 42. 20 In Grimaldi’s opinion, the existing structure is the material that sustains the project. He writes: “Becoming aware of the need for replacement, on the basis of the consistency of the construction materials, their ability to stand up to atmospheric agents or bear a weight, signifies for the architect the possibility of influencing social relations, of not being a mere designer of ideologies. This matter, which proves the consistency and dimension of resources, becomes the framework of reference, the established context in which the project finds a space”, in Op. cit., p. 118. 21 Marco Casamonti, “Trasformazioni”, Editorial of Área, no. 45, monograph on Restauro, riuso, trasformazioni. 22 André Corboz, Op. cit., p. 72.

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23 André Corboz, Op. cit., p. 72. 24 André Corboz, Op. cit., p. 76. 25 On this theme, the German architect expressed some interesting considerations in reference to his work in an interview with Giovanni Leoni published in Área no. 45: “I proceed according to successive strata, in an intervention that is interpretative in nature. I try to insert my architecture by accepting the dimensions and rules dictated by the original and creating the sensation of a reversible intervention. But the changes modify the entire building. There are no formulas, no science. Disregarding the languages used, what is important is that the building can once again be a whole rather than a sum of parts [...] However, as I do not proceed by formal imitation, I am necessarily dealing with a dialectic unity, the product of the combined presence of different languages. Mine is an abstract, not a figurative language; the recovery of an essence of tradition according to a plane of abstraction.”

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Rehabilitating and building using traditional materials. The Egyptian experience

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Bernard Maury Doctor of Architecture Institut français d'archéologie orientale du Caire, Egypt

Principally in Cairo, but also in Syria and the Yemen, the Mission française pour la Sauvegarde du Patrimoine architectural has often been called upon to undertake major rehabilitation or restoration work, in view of the very poor state of conservation of some buildings: subsiding floors, collapsed walls and ceilings that were propped up or had already fallen in made it impossible to use premises. Added to this were varying degrees of modifications that had occurred over the centuries. Faced with this state of heritage, various questions arise: what should be done? What should be kept? Which elements can be suppressed? What kind of work should be undertaken? The initial intervention to be undertaken when rehabilitating a monument is archaeological: restoring the monument to its original condition, or as near as possible, in architectural, structural and decorative aspects. The second is to determine the kind of work required to rehabilitate the monument in question.

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I. Our protection policy 1. Respect for the place Restoration work has always been guided by respect for premises and a constant attempt to return them to their original condition. Once the archaeological study is complete, it is necessary to define the nature of work and, in particular, the different types of materials to be used. A list of those used in the construction of the building should be drawn up as part of the archaeological study. It now remains to implement them. The wide range of different modern materials currently available on the market may seem to have simplified the problem of restoration, and there is a strong temptation to use these materials without proper judgement to restore old buildings. This situation calls for a very careful approach; we have seen the upheaval caused by the advent of cement, 150 years ago, and, as a consequence, of concrete, with the resulting craze they produced, and can appreciate the technical achievements they have generated. But we have also witnessed the catastrophes it brought about in old buildings everywhere: fissuring after repairing stone walls with breeze blocks, salinization and shattering of stones after applying cement mortar bonds, swelling of renders after applying a cement coating to a brick wall, and so on. Many people, from lack of knowledge, have turned to this rapid mixture, thinking that cement was the miracle solution to building problems.

North façade of the courtyard of Harawi house restored using old stone

2. Finding old techniques and materials For restoration work to be entirely satisfactory, it is necessary to find the old techniques and, above all, the materials used to build the original construction, in an attempt to ensure homogeneity. Corresponding to each stage of work is a series of basic questions about restoration, centring in three areas: the use of quality materials, the competence of the workers and funding. In many cases, however, it is unfortunately the third point, the financial aspect, that conditions the first two.

II. The materials 1. Stone A technical study of various samples taken from the buildings in question showed that the original stone used in 17th- and 18thcentury Cairo to construct buildings was a stone of excellent quality. Pinkish in colour, this limestone called gebel ahmar (red stone) has an excellent compression coefficient and is damp

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resistant. However, the quarries had been unworked for a long time, probably because the seams had been exhausted. In Egypt in the 1980s, the only stone used in restoration was a poor quality white stone quarried in Hélouan, near Cairo. In both aesthetic and technical terms, this stone was inadmissible. We insisted to those responsible that an identical or very similar stone should be found to the one that was principally used in construction in Cairo in the Ottoman period. It was in vain, however; the possibility of opening a new quarry was beyond our means. But the idea lingered, and our insistence on using the stone called gebel ahmar in restoration work later bore fruit. Ten years later, when the Mission française undertook another case of restoration in Cairo, the demand for gebel ahmar had grown to the extent that new quarries had opened and were commercializing it. The solution used in our first restoration job was, then, to buy stone salvaged from non-listed 19th-century buildings that were being demolished. This solution was, of course, cheaper… Dressed to the dimensions we required, this stone was the same colour as ours and, most importantly, had the same mechanical characteristics, allowing us to include it in old walls without creating differential tension or shear stress in the event of overload. 2. Brick The problems with brick were slightly different, in that old bricks, comprising a mixture of clay and poorly fired ash, were full of mineral salts as a result of rising damp. This material was difficult to salvage, as the texture of the brick had become friable, and it was necessary to look for an alternative material. We then looked at the possibility of using locally produced fired bricks of similar dimensions and technical characteristics to the ones we needed. Tests were carried out, with the conclusion that this type of brick could, as in the case of the stone, be used to repair old walls without creating differential tensions or shearing. It was subsequently used throughout the site. 3. Wood The problem of timber was also addressed with great care: a general study showed that most of the building’s joinery had been made using Douglas pine, called azzizi in Egypt. In the 1980s, this type of timber, long imported from Turkey, came from northern Europe. The quality, however, though similar, was not satisfactory. As in the case of stone, we turned to beams salvaged from 19thcentury buildings that were being demolished. Once reworked, these beams provided an excellent timber that was very healthy and had over a century of seasoning. The joinery was restored without problems, the old and the new timbers working together in perfect harmony.

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4. Mortars and coatings The examination of mortars showed that they were all lime-based. The same was true of the renderings which, in some cases, comprised a mixture of lime and gypsum, with up to 80% gypsum. However, the main problem with mortars and renderings was how to combat the use of cement. The drawbacks of using a mortar of this type when building a stone wall are well known. Unfortunately, this practice was still very widespread in the 1980s in Egypt and other nearby countries, and it was difficult at the time to convince the artisan workers of the danger of using this kind of mortar. The result was that, due to the lack of demand, lime was practically non-existent on the Egyptian market.

Use of new materials (metal girders) to reinforce old structures

Detail of restoration of the meshrebeeyeh in Sennari house


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Our search in the capital produced quick lime that we had to fetch in bulk directly from the kiln. This was the solution we chose. Although lime-slaking is a long and difficult task, the resulting quality is excellent, producing remarkable results in both rebuilt stone-wall structures and façade renderings. When we worked on a second restoration project in Cairo, in 1995, lime had come into its own. Although several varieties were not available, one type was commercialized in sacks, in powder form.

After carefully studying this case, the chosen solution was to introduce a metal structure into the thickness of the structural floor to relieve the old timber beams. This was possible thanks to the thick infilling between the joists and the flooring. In another case, perhaps the solution of concrete reinforcement would have been preferable…

5. New materials: steel, stainless steel, concrete, tar… The state of buildings, and particularly the new function of these monuments, may call for the use of complementary materials— with certain conditions! Let us take the example of a subsiding floor in a large mansion. It comprises timber joists supporting a heavy limestone flooring. Now, the underside of this structural floor is decorated and must be conserved. At the same time, the structure’s timber beams are too weak to take heavy loads, making it very difficult to reuse the premises. This calls for reinforcement of the structural floor without touching its under surface. In this case, the use of complementary materials is one solution, since despite having a smaller volume, they have greater strength.

There is no such thing as a model solution in restoration; each case must be considered and studied individually. Furthermore, new materials are only used to reinforce an element or structure. They work “under cover” and must not be noticeable when work is completed. In this case, it is vital to dissociate the old and the new structure, to enable them to work separately (problems of deflection, dilatation, etc.), the most important issue being to ensure that the solution adopted is invisible.

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Repair to the brick jamb of a doorway in Sennari house

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The dilemma criteria: The point of view of heritage value

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Irene Hadjisavva-Adam Architect Department of Town Planning and Housing, Cyprus

Buildings are the necessary background for people’s activities. They were conceived in order to cover the needs of people, both utilitarian but also aesthetic and symbolic. The typology and morphology of a building reflects the wisdom, mentality, means and way-of-life of generation of people, but also the historic evolution of the settlement, its socio-economic possibilities, its interconnections and relations with other locations, etc. Thus, the heritage value that a historic building encompasses is not restricted in the mere physical or even townscape characteristics but also more profound values, identities and testimonies. 7

But besides the landmarks or the other monuments of the extraordinary human inspiration such as palaces, cathedrals or other religious buildings, castles, forts, or other public buildings, there also lies the anonymous architecture that forms a significant part of a settlement’s townscape, identity or its “sense or spirit of place”. The preservation of the traditional architecture is not as selfevident as for an important monument. Its heritage value is not judged by the community to be of a national significance. Thus, a building of this quality cannot be restored “per se”, but needs to continue to take part in the settlement’s active life. However, its physical existence and material amelioration is important for several reasons. These can be theoretical, symbolic and abstract such as the historical testimony that they offer, but also pragmatic. A well preserved architectural setting is a comparative advantage in a competitive globalized world. Likewise, a building with historic, architectural and other heritage values carries additional assets in terms of space quality and added value for their contemporary use for both residential and commercial purposes. Contrary to the restoration of monuments, buildings of traditional architecture need to have a continuous and sustainable use. Only when in use they can be maintained and kept “alive”. But not all uses are appropriate for all historic buildings. On the one hand the modern needs demands the addition of new technological, sanitary or other installations and amenities, the re-arrangement of the interior or addition of space. On the other hand, modern materials and techniques make the restoration process easier and less expensive. But these alterations, necessary for the continuation of use or for a new use, once the original has seized to exist or cannot correspond to the modern demands, often undermine the heritage value of the building. This threat brings us

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in front of a dilemma: to preserve the cultural heritage embodied in the structure of the historic building at any cost, or to allow the predominance of the new use? Is there equilibrium between the heritage and the economic and utilitarian value? And where exactly does this line lie? There are no recipes or standard solutions. Each and every building has a different heritage value, problems and opportunities. Thus, every individual building must be judged for itself. The same applies for a building’s setting. Heritage values differ from country to country, but even from one street to the other in the same neighborhood. Similarly, as judgment is a subjective process, the evaluation criteria for the heritage value differ from an individual to an individual. The professional, sensitive to issues of architecture or human history and geography, sees infinite information and value where the ordinary man might only see “stone and mortar”. Similarly, public institutions (e.g. Heritage bodies) attribute great heritage value where the owner only


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attributes “holiday” value. In other cases a Local Authority might wish to deny the existence of the heritage value of a building in order that this gives way to new highways or squares. Even though the judgment of the heritage value of the traditional architecture is subjective and varies according to education, sensitivity or financial or other interests, the responsibility for its preservation is an objective and a requirement for all societies. This responsibility is materialized in the legislation of each country and reflects not only the individual society’s sensibilities but also its obligations according to the international conventions that the country has signed. Concerning the restoration of traditional architecture, the public sector has a mainly regulatory and less often a pro-active role. The initiative for its rehabilitation usually lies in the private sector that undertakes a considerable investment and needs to get more “for its money” than the mere preservation of heritage value. In other words, the objective of any private investment is profit whether this is cash revenue, or the satisfaction of a housing need. In this sense, the attributed heritage value is seen as an obstacle for an increase in the short-term profit that the property has to offer. For that reason heritage values cannot depend solely on individual judgment. In Cyprus, as in many other countries, Public Authorities regulate the rehabilitation process of traditional buildings by including restrictions, design guidelines or other obligations in the Planning Permits (or Consents) for buildings that are characterized as listed or Ancient Monuments.

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The objective of these regulations is namely to help in finding the right balance between heritage values and utilitarian values for each individual building according to its specific qualities. Design guidelines are focused on the material expression of these values and also to the authenticity of the building.

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Systems and equipment installations challenges

Tool 7 The criteria of intervention

Athina Papadopoulou Architect Conservation Architect employed by UNDP-UNOPS for the Nicosia Master Plan, Cyprus

The patterns of contemporary living conditions have added an additional parameter to the challenges presented to professionals when restoring historic buildings: that of the introduction of mechanical, electrical and equipment installations.

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Mechanical and electrical installations pose certain technical limitations regarding their installation both in new and in historic buildings. In newly designed buildings however, it is often the case that the building design is adjusted according to the systems installation needs, whereas when designing interventions for restoration the systems installation should largely be adjusted according to the restoration priorities. Technical limitations of mechanical and electrical installations may include anything from the diameter, length and route of a pipe, to the location of a noisy chiller in the exterior environment of a historic building. Usually, the floors, walls and ceilings of a building are the most vulnerable areas for interventions by system installations. Horizontal and vertical proposed routes for these installations may drastically affect the structural capacity of the historic building, but also the character and use of a space. Equipment installations for kitchens and W.C. can also unnecessarily strain the structure, character, authenticity and use of a traditional building. Firstly, the location of such uses is preferable to be done in extensions to the historic building, especially if the original building never accommodated such uses. Secondly, it is preferable that furniture such as kitchen counters be as detached from the building fabric as possible, or be incorporated in mobile units.

Omeriye Ottoman Baths, walled city of Nicosia

Quite often, a lack of sensitivity on behalf of mechanical and electrical engineering consultants is observed during restoration of historical buildings. Therefore, the architect as coordinator must assume the role of promoting multidisciplinary work in order to safeguard the application of internationally accepted restoration principles in favor of the historic structure. Creative solutions may be reached through restrictions posed by the building itself, technical, programmatic and financial limitations.

Shadow Theatre Museum, walled city of Nicosia

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Tool 7 The criteria of intervention Systems and equipment installations challenges

In an attempt to approach this issue we propose the following as general strategic criteria: 1. Minimal intervention on the building fabric 2. Minimal intervention in the surroundings of the historic building 3. Reversibility of the installations 4. No disruption of the structural capacity of the historic building 5. Retain the character of interior and exterior spaces 6. Easily identifiable elements but aesthetically non-intrusive 7. Easily accessible installations to assure inspection and avoid damages in the case of leakages (especially for plumbing and sewage installations) 8. Respect for pre-existing systems which may have historic or archaeological value 9. Compatible introduction of new uses in certain spaces of a building

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b. Chrysaliniotissa Kindergarten project, walled city of Nicosia The new WC and kitchen were located in the new extension to the listed building, in order to preserve the character and relationship of spaces in the historic building. c. Shadow Theatre Museum, walled city of Nicosia Ducts and pipes are screened by perforated metal sheets and placed in an easily accessible location, without disrupting the wall of the traditional building.

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Some examples of restoration projects in Cyprus, which have successfully integrated systems and equipment installations, can be seen in the restoration of (a) the Omeriye Ottoman Baths, (b) the Chrysaliniotissa Kindergarten project and (c) the Shadow Theatre Museum:

a. Omeriye Ottoman Baths, walled city of Nicosia The new water supply pipes in the ‘’hot chambers’’ were installed at a distance of about 5cm off the outer face of the walls at the same height of the existing terracotta pipes. The original pipes were kept inside the mass of the stone walls as a testimony of the building’s history since their physical condition and contemporary water supply needs did not make it possible for their reuse.

Chrysaliniotissa Kindergarten project, walled city of Nicosia

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Tool 8. Rehabilitation techniques: reinforcing structures

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Rehabilitation of structural elements in Traditional Mediterranean Architecture

César Díaz Gómez Doctor of Architecture Professor of the Department of Architectural Technology I, School of Architecture of Barcelona (Technical University of Catalonia), Spain

1. General principles

3. The functional replacement of the element by a new element that will provide the totality of the required bearing capacity, without necessarily calling for the removal of the element in question. Evidently, the choice of one of these approaches depends on the mechanical requirements and on the capacity of the element undergoing intervention to meet them. d. Singular interventions in buildings with special value heritage In buildings considered cultural heritage, it is important to bear in mind other specific aspects to ensure the preservation of their genuine qualities. This is why concepts such as the reversibility of the interventions undertaken, enabling the elimination of the effects of the intervention, may be considered a priority in the choice of technique. Or, in another, more essential area, the decision to restore what exists using the original techniques, provided the functional application of these techniques complies with the demands of the intervention, may need no further argument.

The wide range of techniques for application in the structural rehabilitation of traditional Mediterranean architecture calls for some general principles to guide the selection of interventions to be undertaken in each different situation. Before referring to each of the various procedures and techniques available, I will outline the key aspects of the intervention, irrespective of the specific objective or problem to be solved. a. Knowledge and adaptation to the technological context of the place Applying specific techniques using the resources available in the place, in as natural a way as possible, using the knowledge and experience of the sector’s workers, is the fundamental priority of the choice. Furthermore, in almost all cases it will represent a financial saving on the intervention in comparison with other possible solutions and, probably, increased compatibility and adaptation to the characteristics of the original construction techniques. b. Considering the repercussions of the intervention as a whole It is important to remember that interventions, no matter how specific their objectives, may have a variety of complementary effects, which should be considered in our choice. For example, reinforcing an exterior wall by applying an extra thickness of sprayed concrete may also provide waterproof cladding, and the addition of a reinforced compression slab to a floor structure may also make it more soundproof. It is also necessary, however, to consider the possible negative effects of the intervention, such as modifying spaces by adding summers or pillars, or the future need for specific maintenance operations for added elements. It is, then, particularly advisable to consider all of these effects, favourable and unfavourable. c. Clarity of the mechanical-structural approach When undertaking structural rehabilitation, it is advisable to clearly specify the technical objective behind the proposed intervention. There are three possible approaches: 1. Recovering the initial bearing capacity of the element in question. This is what is usually interpreted as repairing the damaged element. 2. Increasing the bearing capacity of the element in question, usually interpreted as the reinforcement of the damaged element.

2. Interventions in walls and pillars The materials and masonry habitually used in the thick walls of traditional architecture, particularly those built of earth and stone, have in common a low level of resistance to the tensions of traction and shearing, and alterability in contact with water due to the high permeability of earth or of many of the mortars used. According to these particularities, we can deduce some general guidelines for intervention in these elements, which, together with the above, condition the choice of repair or reinforcement technique to be used in each case. Specifically, whatever technique is chosen, it is advisable to ensure an even distribution of stresses in order to prevent, as far as possible, the additional tensions of traction or shearing. It is also advisable not to increase compressive stress, given the difficulty of characterizing this form in most old walls by means of testing. And, finally, it may be useful to remember the possibility of absorbing stress by using the transversal plane of the wall as a resistant resource that can counteract thrusting. Below is a commented list of the most habitual techniques of intervention in these elements.

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a. Physical replacement of the damaged part This consists of removing the material from the part of the element that is damaged, either by cracks, bulging or alteration, and reconstructing it using the same material or others with similar characteristics of resistance and deformability. In walls or pillars of stone or brick masonry, it is habitual to use the same materials in the replacement, and brick masonry tends to be used in adobe or rammedearth walls. In all events, the aim of the intervention is to restore the initial bearing capacity of the damaged element. It is important to remember that this type of intervention requires the prior elimination of the cause of damage or verification that the damage is now passive and has ceased to be a cause. During replacement work, particular attention is needed to contact between the new and the pre-existing elements, in order to ensure the correct transmission of loads and similarity of mechanical behaviour.

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b. Stitching cracks The method consists in placing stronger, more rigid elements between the edges of the crack to act as sutures, such as metal bars, pieces of brick masonry, etc. The aim is to restore lost continuity to the wall, so that tensions can be transmitted and once again distributed homogeneously throughout the cracked area. To be effective, the crack must be passive—that is, the original cause of cracking must no longer act on the area being repaired.

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c) Injections This is another system of repairing passive fissures and cracks applicable to walls of brick or irregular coursed masonry that consists of injecting a liquid to entirely fill the space between the edges of the opening. When it hardens and adheres to the material, this liquid restores the continuity to the damaged element. The characteristics of the liquid, usually epoxide-based, and the pressure at which it is introduced vary according to the materials in the wall and the size of the space to be filled. Superficial sealing prior to injecting the fissure or crack must be able to stand the pressure of the liquid before it hardens.

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d) Repointing This procedure involves restoring the initial strength of stone or brick masonry and consists in refilling mortar joints that have been damaged by erosion or the effects of plant roots by introducing products of variable density or viscosity by means of gravity or infusion, according to the technique employed.

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e. Thickening using mortar or sprayed concrete This process involves increasing the section of the damaged or undersized wall by applying layers of material (mortar or concrete) to its facings over the incorporation of metal reinforcements joined through the wall. The reinforcement can be applied by placing formwork parallel to the faces of the wall and discharging the concrete, by projecting the mixture against the walls once the reinforcement is in place, or guniting. The procedure used is chosen according to the required thickness and the increase in resistance assigned to the reinforcement. This very versatile solution can be adapted to complete wall structures, entire walls or specific stretches of a wall. This makes it particularly appropriate for reinforcing buildings affected by seismic movements, since it increases the rigidity of the parts of the building that require it or, as applicable, of the entire building.

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f. Ties The purpose of ties in wall structures is usually to prevent their collapse or progressive deformation transversal to their plane by implementing linear elements under traction called ties, generally made of steel cable and fixed to two parallel walls by special anchoring elements to prevent separation and, consequently, the corresponding loss of resistant capacity. It is advisable to implement at least one anchoring element that can be periodically tensed to compensate for possible extension of the tie material.

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g. Abutments The function of abutments is equivalent to that of ties, though they are practically obligatory if the building does not have sufficiently rigid elements to absorb the specific tensions generated at the points at which ties are anchored. In these cases, the thrust of vaults, arches or any other element that introduces stress at an angle to the walls, can be absorbed by abutments, thanks to their capacity to transmit this action to the ground via their section. The design and dimensioning of a new abutment requires attention to the degree of settlement needed for correct functioning. .

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h. Strapping The implementation of straps or hoops in buildings with closed wall structures or brick masonry or stone or brick pillars, encircling them to make them more slender and increase their resistance, is a historically used resource that is found in many well-known old buildings, such as the Coliseum in Rome or Italy’s medieval campaniles. Iron and steel are the materials traditionally used for these elements. Today, strips of carbon fibre can provide the same function in some cases, though it is necessary to consider the effects of the adherent material on the reinforced element.

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i. Steel bar reinforcement This is an integrated reinforcement system for stone or brick masonry walls that consists in inserting steel bars into the interior of the wall, set in perforations of variable lengths that may be as long as several metres, thereby generating secondary bar structures inside the walls and increasing overall strength or creating more rigid parts that can homogeneously distribute descending stress. The interface between the steel bars and the material of the wall is filled in with an adherent compound, usually epoxy-based.

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3. Interventions in structural floors and roofs Interventions in structural floors comprising timber beams and joists must be based on prior diagnosis of the causes of the dysfunctions, be they the attack of biotic agents, natural shrinkage or deficiencies in the dimensioning of the floor structure in relation to the mechanical stresses it receives. The choice of the intervention requires knowledge of future conditions of use and the need for conservation not just of the elements treated but also of those that may be affected by the planned intervention, such as false ceilings or floors with outstanding artisan or pictorial values. Below is a list of the most usual forms and methods of intervention in these elements. a. The functional replacement of beam and joist supports Fungi and termite attacks are often concentrated in the supports of timber beams and joists, particularly when they coincide with exterior walls, due to the special conditions of damp and darkness that converge in these points. These cases usually require the functional replacement or reinforcement of the supports affected by the decomposition of the wood. The choice of one of the many existing procedures must consider the degree of generalization of the problem to single joists or to a whole stretch of supports, the characteristics of the wall on which they rest, the available techniques and the formal appearance of the chosen solution.

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b. Beam and joist reinforcements This involves introducing new flexion elements that collaborate to absorb the stresses affecting the beam or joists that are insufficiently dimensioned or when the effects of timber shrinkage have produced excessive deformation. The materials employed are usually timber or steel bars, and they may be positioned at the side, above or below the element requiring reinforcement. They are positioned above if it is necessary to conserve the appearance of the existing floor structure due to the presence of valuable paintings or false ceilings. They are most usually positioned beneath when reinforcing joists in floor structures if it is possible to reduce the headspace of the rooms they cover over. The side position is most commonly employed to reinforce timber beams that support entire stretches of floor structures of joists, generally in the form of two elements joined by stud bolts through the beam in question. There are a variety of hypotheses for dimensioning reinforcements depending on the possibility of collaboration between undersized or damaged elements and previous deformations in order to bear the load jointly with the reinforcement.

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c. Struts Struts are a simple, efficient solution for reducing tensions as a result of flexion introduced by overload and deformations derived from timber shrinkage. They comprise timber or steel beams arranged crosswise to the one requiring reinforcement, dividing its span in two or three. A solid support for the strut formed in this way is usually the determinant aspect in the choice of this solution, since it requires bracing walls that are sufficiently resistant or, otherwise, specially built pillars with their corresponding foundations to correctly transmit loads from the strut to the ground.

8 d. Addition of reinforced concrete slabs The addition of reinforced concrete slabs connected to the timber joists in a structural floor is one of the most used solutions in building rehabilitation today. Reinforcement takes the form of converting existing joists into mixed beams of timber and concrete, and the possibility of coplanar distribution of tensions produced by flexion throughout the plane of the floor structure, increasing the overall rigidness of the building when the new slab is joined to the thick walls around the perimeter, a measure that also improves seismic resistance. At the same time, the addition of concrete improves the soundproofing of the floor structure. The most critical aspect is the solution used to connect the new slab to the existing wall, since it is conditioned by the wall’s rigidness, cohesion and perforability, which can be very variable and unpredictable.

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e. Specific interventions in roof frameworks and trusses The fact that these elements are the most exposed to damp often points to the advisability of replacing them. They may however be reinforced if their general condition, size or an interest in their functional maintenance make it advisable. Obviously, the functional replacement of supports and their regularization, arranged as far as possible on a rigid main beam in order to distribute loads evenly to the walls, is often necessary and recommendable. To reinforce principal rafters, ties and knee braces, it is becoming increasingly common, if they are to be left visible, to use post-tensioned frameworks to compensate for traction or to generate a new distribution of stress.

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f. Specific interventions in arches, vaults and domes Some of the solutions listed for reinforcing floor structures are also applicable to arches, vaults and domes. Metal ties are typically used to reinforce arches and vaults, positioned in the area of the extrados under traction. The resistant edge of arches can be increased by the introduction of steel bars from the intrados. In some segmental vaults, steel or reinforced concrete ties absorb the thrust generated at the base. Reinforced concrete slabs can serve to strengthen vaults and domes by connecting them on their extrados. Each individual case requires consideration of the suitability of a given solution in relation to an alternative that preserves the original construction method, with reversibility of the intervention as a vital requisite.

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4. Interventions in the foundations The decision as to what type of intervention to undertake when a building is subject to problems deriving from site movement requires knowledge of the type and characteristics of the foundations, monitoring of the activity and information about the geotechnical characteristics to a sufficient depth on site. Only after compiling this data and effecting this analysis can a judicious decision be made. In fact, one of the most important decisions to be taken in this initial phase is whether or not to undertake an intervention that modifies the conditions of the original foundations or improves the terrain. If the building’s foundations are of the most common superficial type, the usual system of underpinning is to implement rather wider footing beneath the existing foundation. This must be calculated in each case, according to the characteristics of the terrain, the foundations to be underpinned, the depth and breadth of the new footing, and the width of the excavations beneath the existing foundations. These days it is increasingly frequent to use a vertically sloping arrangement of micropiles, which compromise a larger volume of ground to absorb the stress in the foundations, using them as a pile cap. Less common are the systems based on increasing the width of the foundation base, due to the difficulty of absorbing the shearing stress at the point of contact between the new and the old foundations. Likewise there is little recourse to the use of conventional piles, due to the cumbersome apparatus they require, or the improvement of terrains by injecting chemical products, which are only suitable for certain types of terrain that are sufficiently permeable.

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Bibliography

MELE, M. Esempli di intervento per la riparazione e il rafforzamento di edifice di abitazione. Prescrizioni per l’edilizia nelle zone sismiche, presentation at the ASS.I.R.CO Congress, 1980

Agence nationale pour l’amélioration de l’habitat (A.N.A.H.). Les planchers anciens, éditions du Moniteur, 1979, Paris

MUNAFÒ, P. Recupero dei solai in legno, Dario Flaccovio Ed., 1990, Palermo

BAGLIONI, A., GUARNERIO, G. La ristrutturazione edilizia, Hoepli Ed., 1980, Milan DI STEFANO, R., Il consolidamento strutturale nel restauro architettonico, Edizioni Scientifiche Italiane, 1990 GALLONI, F., ED. Consolidamento e recupero dell’architettura tradizionale: degli intervente singoli agli intervente d’insieme urbano, ASS.I.R.CO IV Congresso Nazionale, Ed. Kappa, 1992, Rome Il restuaro delle costruzione in muratura. Problema metodologi ed tecnique di consolidamento, Ed. Kappa, 1981, Rome LÓPEZ COLLADO, G. Ruinas en construcciones antiguas, Ministerio de la Vivienda, 1976, Madrid Manual de diagnosi i intervenció en sistemas estructurals de parets de càrrega, Col·legi d’Aparelladors i Arquitectes tècncics de Barcelona, 1995, Barcelona MASTRODICASA, S. Dissesti statici delle strutture edilizie, Hoepli Ed., 1978 (6th edition), Milan

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PASTA, A. Restauro antisismico, Dario Flaccovio Ed., 1992, Palermo ROCCHI, P. Progettare il consolidamento, Ed. Kappa, 1983, Rome Tratado de rehabilitación, Tome 1: Patología y técnicas de intervención. Elementos estructurales, Departamento de Construcción y Tecnología Arquitectónica, Universidad Politécnica de Madrid, éditions Munilla-lería, 1998, Madrid


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Reinforcement and treatment of foundation. Egyptian experiences

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Wahid El-Barbary Architect General Director in Sector Projects of the Supreme Council of Antiquities, Egypt

All the engineered structures on the earth, including earth fills, dams (both earth and concrete dams), buildings, and bridges, consist of two parts, the upper or superstructure, and the lower or foundation. The foundation definition is the interfacing element between the superstructure and the underlying soil or rock. Foundation engineering is the art and science of applying engineering judgment and the principals of soil mechanics to solve the interfacing problem. It is also concerned with solutions to problems of retaining earth masses by several types of structural elements such as retaining walls and sheet piles. Foundation engineering is also the art and the science of using engineering judgment and the principal of soil mechanics to predict the response of the earth masses to change the conditions of geometry and loads. It should be noted that foundation engineering has been defined as the art "art and science" of applying engineering judgment and the principals of soil mechanics. Soil conditions is one of the main causes of defects in masonry structures is differential settlement due to changes in soil properties with time due to rise in ground water level for instance. It is also widely recognized that structural damage due to earthquake is very much influenced by soil conditions. In general, the amplitude and duration of shaking depend on the depth and softness of the soil at the site. The engineer must obtain sufficient information to evaluate the load-bearing capacity and the dynamic amplification characteristic of the soil. For sites with high geological hazards, such as soils susceptible to large settlements, extra-sensitive soils, or soils with a high probability of liquefaction, a special geotechnical investigation is required. In certain circumstances, however, it may be appropriate to carry out seismological and geotechnical investigations that go beyond the minimum requirement of a building code. This may be the case, for instance, when ground motion amplifications due to site conditions or effects of ground-structure interaction are deemed to play an important role in the behavior of the structure under investigation. Furthermore, geotechnical investigation may need to be undertaken for exploratory or remedial measures. For the various types of foundations, we distinguish between many types of foundation used to support buildings:

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Shallow foundations (footings or spread footings) like continuous foundation under the walls, the width of the foundation is little bit larger than the wall, generally we use stones and mortar for building foundations. Deep foundations (pile or caisson foundations) are used when the resistance (bearing capacity) of the soil is not enough to support the up structure. Many kinds of deep foundation exist since the old ages using stones and mortars, woods piles especially when the water table is very close to the surface. The bearing foundation, in this case, is the sum of the lateral bearing capacity and local bearing capacity. Choosing a method to reinforce and treat a foundation of an old and traditional depends on the knowledge of raisons of degradation origins: settlement, increasing in load, modification in the structure geometry, earthquake, explosion, water table changing or/and chemical actions. We consider that the foundation treatment must follow the following recommendations: Realization of geotechnical studies for foundation soil, inspection and diagnostic the foundations and known the stat and actual situation. The choice method or reinforcing depends

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on the report of geotechnical experts and their recommendations The reinforcement of underground foundations doesn’t need to conserve the Building like the upper part of structure. Many methods exist to reinforce the foundation: Reinforcing existing foundations. Using micro-piles. Strengthen soil using modern solutions.

Reinforcing existing foundations

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One of the methods is to strengthen and buttress the existing foundations by adding extra mass to the existing foundation, attach the new mass to the old foundation by means of steel strain, anchor bolts and ties and to create a foundation system, such that the entire foundation does not move laterally. To reinforce the foundation of an old wall, we start by determining the load of structure (stones, filling material...), and the bearing capacity of the foundation soil. If the results show that the dimension of the actual foundation is not enough to support the structures with realistic security function, we can increase the foundation surface. The additional foundation must be connected to the old part by using bars, cables etc. Before starting the reinforcement of the old foundation, a complete system of reinforcement must be done to keep the stability of the wall and the structure. The concept of strengthening and buttress the existing foundation can be adding extra mass when the problem of settlement does not exist (hard rock). The mass can be built in the side of the existing foundation; the new masses is attached to the old foundation by using strain steel bolts, anchor bolts, and ties and create a foundation system. Such that the entire foundation does

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not move laterally. The action of enlarging the foundation is more effective when widening the raft beyond the external edge of the construction, as the pressure bulb will also spread over a larger area of the transferring loads to the deeper and more resistant strata of the soil. Using underpinning can represent the only reliable solution when it is not possible to stop the settlement in other way. Underpinning ancient buildings must always be considered as a last ditch solution. This solution, when adopted for shallow foundations, can give problems during the boring phase, as softening of the soil can occur during the course of the works, as some parts are underpinned whilst others are still on deformed soil.

Using micro-piles to reinforce the foundations of historic monuments When subsoil has an insufficient bearing capacity or/and the resistance soil is located at an important depth, we can use piles, micro piles or deep foundation to reinforce the stability. Different solution is using modem technique to reinforce old structures. Micropiles are one of the largest growing segments in deep foundations today. Also known as "Pin piles" or "Minipiles", Micropiles are small diameter, high capacity pipe piles. They are typically specified in short threaded lengths and installed through various drilling techniques. The addition of grout and threaded bar reinforce the pile in lateral, tensile, and compressive loading. Micro-piles can replace conventional piles under most circumstances, and are especially economical where there are difficult ground conditions (caving, ravelling or rocky ground conditions) or where there is limited or difficult access or workspace, like inside buildings for earthquake upgrades. Micro-piles are installed much like tiebacks or soil nails,


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using rotary or percussion drilling rigs. Because of their smaller size, a wide variety of drilling techniques can be employed more economically, which makes their use so attractive: flight auger, tricone, percussion rod, down-the-hole-hammer, casing with auger,

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hollow grouting drill (Titan), percussion rod etc. Micro-piles are widely accepted within engineers and designers who are replacing traditional piles with micro-piles - to the benefit of the owners.

Example: Under foundation soil injection in Monumental building (Exemple du complexe Qalawoon) Due to the raised level of under ground water, this water moves continuously and carryout the soil particles, which made many voids in the soil, this gives us inhomogeneous behavior of soil. To have a consolidated soil with a good bearing capacity and a homogeneous section we needed to fix up the sewerage system, also fixing the under ground water level to stop water currents. Then soil injection process takes place, first drilling in the soil to the specified levels then inserting a valved pipe that the cementation material will be injected through it with a pressure will not exceed more than two bars. The soil is injected with a beginning injection grout consists of 1:4:0.50 cement: water: bentonite. After 24 hours of the primary injection we begin the final injection with a higher cement ratio with additives which is comp last 431 to give a plasticized grout to be injected to the soil to give the required soil core tests & the required soil bearing capacity.

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Technological and structural aspects in the conservation of Old Akko

Ofer Cohen Engineer Israel Antiquities Authority, Israel Yael F. Na’aman Architect Conservation Department of the Israel Antiquities Authority, Israel

This essay deals with technological and structural aspects of the conservation of building remains in Old Akko. The basic concept is one of authentic conservation by means of preserving the original materials and facades without disturbing the ongoing everyday live in the city. The source for the information presented below was derived from physical-engineering surveys that were conducted in the city over the past decade.

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Damage to Buildings and Material Decay Damage is a condition in which the building has partly or completely lost its load bearing capability and is liable to collapse partially or entirely. The damage is usually marked by such causes as cracks, collapse, crushing, crumbling and the breaking away of and deformation of elements. Decay is the deterioration and weathering of the material, a condition that usually leads to a reduction in its resistance and increased brittleness and porosity. The process whereby material is lost stems from physical and chemical action and usually begins on the outside and works inward. The mechanisms of damage and decay are actuated by a number of factors: the absence of proper maintenance, the lack of scientific knowledge, the use of a construction beyond its life expectancy, imperfections in the original design and the introduction of new factors that were not foreseen. All of these factors lead to a reduction in the structural strength, in other words, the reduction in the load bearing capacity together with an increase in the effects of the actions involved. Three factors are at work here: the kind of action, the quality of the materials and the type of structure. The action involved can be some sort of dynamic or static mechanical action, and a physio-chemical action linked to the atmosphere and environment. The materials’ resistance is effected by the climate and weathering as a result of physiochemical processes. The decay is connected with the natural environment such as humidity, rain, temperature fluctuation; and factors such as traffic, pollution and the lack of maintenance also accelerate natural processes. Decay can be chemical, physical or biological and is related to environmental factors, the characteristics of the building materials and the specifications that protect the building (e.g.: roofs, drain pipes). The structural behavior depends mainly on the kind of materials used, the shape and size of the structure, connecting specifications between the elements and the environmental conditions that border on the

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The Old Akko (Israel)

building. Damage is caused due to an increase in the mechanical action and reduction in the structural efficiency, whether from natural phenomena or as a result of an action caused by man. When these occur without careful control they can negatively impact the building (Croci 1998: 41-46). Old Akko was built of kurkar masonry stones (walls and vaults) held fast by lime based bonding materials and wood that was used in the roofing, window and door specifications. Other elements were also used such as hard limestone (for the cantilever steps, pavement in public spaces, window openings and decorated elements) and marble. In later periods materials such as terrazzo pavements and painted concrete, iron beams, Marseilles roof tiles and of course concrete were also utilized. In recent years we have witnessed the use of a variety of modern materials, among them surfacings, plasterboard walls, aluminum and ceramic.


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The most common structural problems in the Old City are concentrated in the buildings’ walls, vaults and ceilings. Each one of these is characterized by problems that stem from the construction technique, quality of the building materials, the destructive factors of the building and the decay factors of the material. The Processes Characteristic of Building Disintegrating Two factors are destroying the buildings in Akko: (1) the decay of the material –weathering as a result of natural processes; (2) damage as a result of human intervention. The natural process of material decay is influenced by an especially high level of humidity and moisture, as well as salt crystallization, the properties of the air, ground characteristics, water (precipitation and proximity to the sea), temperature and man’s intervention with improper maintenance. Damage caused by the direct intervention of man is commonplace, for example: the renovation actions where unsuitable materials were used; when part of the building is dismantled in order to adapt the built space to the user’s needs or for the purpose of clearing an area needed for new construction, in order to create new access routes or improve existing ones; dismantling part of a structure so it can be put to secondary use elsewhere, or dismantling for the purpose of removing an immediate danger. A schema of the disintegration process of buildings includes prolonged decay of ceiling joists on the upper story until they collapse, an accelerated process of the walls falling apart on the upper story and of the vault on the ground floor and the continued disintegration of the building’s outer walls. 1. In the wake of the collapse of a wooden ceiling on the upper story the walls remain, standing tall and thin relative to the surroundings. The danger in this situation is that the stability of the walls will be undermined that will result in several stones falling or the collapse of wall sections. The solution in this case is to stabilize the remains by creating a flat element on top of the walls and/or a support anchored to the vault. 2. Collapse of a wooden ceiling on the upper story and of the vault on the ground floor and the partial disintegration of the walls. In this instance remains are created that are tall relative to the surroundings and the remains of the vaults are unstable. The solution to this is to restore the spatial function to the ground floor and/or support the remains to the ground or an adjacent structure. 3. Collapse of a wooden ceiling on the upper floor and the vault on the ground floor and the disintegration of the building’s outer walls. In this situation a protruding stump remains that is not stabilized by the vault. The solution requires stabilization of the vault stump or the controlled removal of dangerous parts.

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Structural problems

Wall damages

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The described disintegration schema is also valid in three story buildings in which there are two wooden ceilings borne atop a vaulted story. The most significant and common factor in the disintegration processes in the city is the inclination of the walls, in other words their becoming out-of-plumb. It can be said that all of the instances of building disintegration in Akko stem from a lack of proper maintenance or as a result of physical damage. These factors cause a chain reaction of prolonged damage and decay and constant deterioration in the physical condition of the building.

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Double-faced Walls Most of the walls on the ground floor in Akko are built of two rows of stones with a debesh fill in between. The construction was carried out in horizontal rows: first one course of stone of the outer faces of the wall was laid and the space between them was filled with debesh and afterwards the second row of stones was laid in the same manner and so one, one course of stone atop another. The walls’ outer faces were built of dressed kurkar masonry stones but the repairs that were made were done with stones that were not dressed. The core of the wall consists of small stones and bonding material. In the construction of the city extensive use was made of two kinds of bonding material, one based on lime and the on soil. Most of the walls are 80-120 centimeters wide. Their primary function is to bear the load from the vaulted story and to direct loads from the tall walls (one stone wide) of the upper stories. The initial impression one gets from looking at the walls is that they are homogenous. Nevertheless, when we observe the crumbling bonding material in areas where the wholeness of the wall was damaged or in instances of decay, a different picture is revealed: the walls’ building material and the construction mass are undergoing a process of disintegration. We can classify the walls in Akko into four types: Type 1. Regular construction utilizing stones that have five dressed surfaces. The height of the stone and the course is c. 45 centimeters; the stone is 50-100 centimeters long and the width of the joint between the stones ranges from 5-10 millimeters. In general we can say that the quality of this type wall is quite good. Type 2. Regular construction utilizing stones that have five dressed surfaces. The height of the stone and the course is 18-37 centimeters; the stone is 18-45 centimeters long and the width of the joint between the stones is 5-10 millimeters. The quality of the wall is usually good. Type 3. Regular construction using roughly hewn stones. The height of the stone and the course is 23-40 centimeters; the stone is 18-60 centimeters long and the width of the joint between the

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stones is 5-10 millimeters. In general we can say that this type wall is of average quality. Type 4. Irregular construction utilizing quarried stone. The size and shape of the stone varies and the courses are not of uniform length. The width of the joints is not uniform and the vertical joints frequently extend through more than one course. The quality of the wall is poor. Walls such as these mainly occur as repairs or retaining walls. Most of the walls’ structural problems involve: a lack of stones in the wall’s outer surface, structural faults in the outer surface, cracks, faults in the plane of the wall that are mainly characterized by horizontal shifts, voids in the core of the wall or bonding material that is missing from the core of the wall. These problems are caused due to the use of inferior quality materials, the tops of the walls that have not been sealed, percolating water, the crumbling of bonding materials, mechanical damage, as well as wear and erosion of the core of the walls leading to the formation of voids inside them. Frequently wear occurs when the bonding materials gradually crumble and are washed away through cracks and joints that were emptied by this process. In addition to these one must add the absence of ongoing maintenance which accelerates the natural weathering processes. Lack of Stones A number factors lead to an absence of stones from the outer surface of a wall: 1. Direct mechanical damage to one or more stones leading to the localized loss of stone. Such damage usually results in other stones falling from the wall. One or several stones suffering from intense wear will cause one or more stones to fall from the course above it. This process will stop when the damaged area is re-stabilized. 2. Poor construction quality of the wall. In this instance the inside surface that comes in contact between the different courses is rather small, the depth of the stones is small and they are not sufficiently anchored to the wall. Because of this a minimal amount of pressure will lead to the detachment of the stones and their falling. 3. Collapse of a section of the outer face of the wall as a result of deformation caused by distention. 4. Removal of a wall or partition perpendicular to the wall will result in damage to the wholeness of the wall, to loss of stones and accelerated decay. The objective in treating missing stones is to restore the original loading bearing capacity of the wall, to integrate the outer surface as an inseparable part of the wall and renew the original constructive system.


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Restoring localized stability by completing the stonework

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Restoring extensive stability through the use of supports

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Possible solutions in this case are: (1) restoring limited and relative stability to the region; (2) a more extensive restoration of stability through the use of supports. Stabilizing by completing the stonework is a preferred solution from all aspects of the building’s conservation. The installation of supports is suitable as an intermediate phase in the stabilization process or in cases in which the deformation in the wall calls for it. Structural Deformation This condition is characterized by a section of the wall protruding from the original line of the building. This phenomenon is a result of a number of destructive mechanisms: Cracks and/or voids in the core of the wall creating an excess load on its outer surface, which leads to distention followed by the collapse of the same section of wall. Detachment of the outer surface of the wall from the core due to the absence of sufficient adhesion properties. A process that accelerates the distention is the crumbling of the bonding materials and its falling into the space between the core of the wall and the outer stone surface. In this situation the bonding material acts as an accelerator in the deformation process. The objective in this situation, like the previous one, is to restore the wall to its original loading bearing capacity, to reattach the outer surface of the wall and renew the original static system. Possible solutions: fill the voids in the core of the wall (grouting) and pointing up the joints, install anchors or dismantle the affected wall section in order to rebuild it.

Building Remains The property that differentiates building remains from wall remains is the possibility to restore their spatial-structural function. A number or combination of factors brings the building to a state where it will be defined a remain, for example the collapse of a vaulted ceiling due to sundry reasons such as excess load; wall stability that is low relative to the lateral pressure of the vaults; failed implementation; collapse of one of the load bearing walls; collapse of a wooden ceiling due to various reasons such as natural wear; moisture problems that lead to enrooting in the wood beams; excess load; wall deformation or an act by man such as the opening of new access routes or the removal of a space for the sake of a new structure. In all of these cases accelerated wear of the ceiling and walls is apparent prior to the collapse. The objective in this situation is to stabilize the different structural elements and, to the extent possible, restore its spatial function. In buildings that are only slightly damaged, it is preferable to restore the spatial function by means of constructing a ceiling using traditional technology while at the same time replacing the missing stones. In reality, building remains in an advanced state of destruction are currently not undergoing conservation in Old Akko and they are either being demolished intentionally or neglected. Wall Remains This element includes walls of various heights and widths, suffering from different degrees of damage, without any

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Support on the ground floor – from one side (detail – separation layer)

Support from an adjacent structure

possibility of restoring spatial function. A number of factors or a combination of them leads to this situation: A wall that was originally part of a building that was destroyed and today nothing remains of the original spatial context. The quality of the construction is a significant factor in the condition of the walls; when this is extremely poor we notice the accelerated decline in the constructional properties of the structural element or of the entire building. A wall that was originally built as a single element and part of it was destroyed by a natural process, such as stone or core erosion as a result of weather damage leading to the collapse of a section of the wall; the defective sealing of the top of the wall or the absence of sealing in this case intensifies the rate of erosion and its toll. In addition to these we should add the human factor which manifests itself through the creation of new approaches or new construction.

Tall Walls or Walls that Constitute an Immediate Danger Remains of these walls are tall (thin walls that are more than 1.5 m higher than their surroundings) and constitute an imminent danger and require temporary or permanent spatial support, during the course of conservation and renovation work and/or after it. Conservation measures in these instances will include preparation and stabilization of the wall in accordance with its characteristics, filling cracks and voids in the stone, repair one or more worn stones, pointing up joints and the installation of supports. In tall walls the preparation measures will include the removal of loose materials from the top of the wall, removal of loose and weakened materials in the areas where plaster is missing on the inside of the wall and the removal of loose bonding material from the joints on the outside part of the wall. Conservation measures will include stabilizing and sealing the top of the wall, replacing missing bonding material in the joints and replacing missing plaster while at the same time creating a straightened surface.

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The objective in these instances is to stabilize the wall, remove any immediate danger and ensure that the wall can carry the anticipated load. Low Walls In this category we include walls that stand no higher than 1.5 m above their surroundings and which do not represent an immediate danger. For example, a 1 meter high wall located on the roof of a building may be considered dangerous because its height above the ground exceeds 1.5 m. However, wall remains less than 2.5 m are considered stabile if the wall’s height does not exceed five times its width when it is structurally complete.

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In double-faced walls, the preparation will include the removal of loose stones, loose core materials and crumbling bonding materials from the joints. The stabilizing measure for these walls will consist of replacing missing stones and back filling them with bonding material, completing missing stone courses to the extent required, pointing up joints and sealing the top of the wall. In both instances conservation measures are required for weathered stones, filling voids and cracks in stone, and pointing the joints as part of the measures for stabilizing the wall.


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Support on an upper story

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A section of vault remains prior to stabilization

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Supporting Tall Walls Supporting tall walls is considered a short-term measure until a permanent solution is provided for stabilizing the wall. In any case the preferred objective is a spatial solution, in other words completing the building. As a rule, the design of the supports will include a specification of a wooden layer that separates the new materials from the stone. Possible solutions: Vault Stumps Sections of vaults and arches in different states of preservation are integrated in the city’s building remains. The remains of the vault are limited in size and the most common phenomenon is the survival of the vault’s springing connected to the upright walls in the stable part of the building. In most instances the vault remains constitute an immediate danger owing to their height and location above a passage. The immediate danger is one of stones falling into the space below them. The destructive mechanisms that lead to this condition are the collapse of the vault due to different reasons and/or intervention by man in order to open passages or remove a room for the sake of a new building. The objective in this case is to stabilize the remains and remove any imminent danger of stones and other parts of the vault from falling. Sometimes it is sufficient to stabilize the core, but when the angle between the top of the vault’s upper stone and the vertical is less than 30°, the upper stone needs to be anchored to a stabilized core, or conversely it should be removed out of safety considerations.

Conclusion The structural problems in Old Akko were surveyed many times as part of the ongoing measures conducted by the Antiquities Authority in city. Analyzing and understanding them has led us to conclude that in many instances the root of the problem lies in inferior construction and the use of poor quality materials. The most significant factor in the state of the physical preservation is the long-term absence of proper maintenance and the lack of awareness. This fact has accelerated the action of the destructive mechanisms and the natural decay that is occurring in the city. There are different ways to conserve the building elements in the city. Choosing a treatment is a stage in a methodical and structured process that includes identifying the problem, understanding the historic and active factors at the site, formulating a theoretical concept for treatment based on a broad perspective of the aspects bound up in the conservation of a historic city, and planning and implementing conservation measures using the resources available to the property owner and the conservator working on his behalf. On more than one occasion a conservator has found himself with his hands tied owing to budgetary constraints. The actions taken in the city’s residential buildings over the past decade were mostly determined because of demolition orders issued for the removal of a danger and not because of the resident’s pro-conservation attitude or an overall broad conservation concept adopted by the city. We are hopeful that things will change in wake of the city having been declared a world heritage site and the approval of a new local master plan.

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After the treatment to stabilize the core and anchoring the top stone

8 References BISCONTIN G. 1998, Compatible Materials for the Protection of European Cultural Heritage Pact 55. Greece. BREBBIA C. A. 1991, Structural Repair and Maintenance of Historical Buildings III. Boston. BREBBIA C. A. 1991, General Studies 1: Materials and Analysis. Boston. BREBBIA C. A. 1991, Dynamics 2: Stabilization and Restoration. Boston. COHEN O. 2000, General Structural Detailing for Characteristic Problems in Stone Masonry in the Old City of Acre, thesis. Katholieke Universiteit. Leuvne CROCI G. 1998, The Conservation and Structural Restoration of Architectural Heritage. Great Britain. FEILDEN B. M. 1982, Conservation of Historic Buildings. London. GIUFFRE A. 1995, Statics and Dynamics of Historical Masonry Buildings. Rome. HEYMAN J. 1998, Structural Analysis: A Historical Approach. Cambridge. HEYMAN J. 1995, The Stone Skeleton. Cambridge. ISRAEL ANTIQUITIES AUTHORITY, Conservation Files Archive, Rockefeller Museum, Jerusalem. LOMBARDO S. 1997, Restauro Strutturale. Rome. MASTRODICASA S. 1978, Dissesti Statici Delle Strutture Edilizie. Milano. PICCIRILLI C. 1989, Consolidamento Critico. Rome. ROCCHI P. 1998, Manuale del Consolidamento. Rome. SHADMON A. 1972, Stone in Israel. Jerusalem. TASSIOS T. P. 2000, Dimensioning of Interventions (Repairs/Strengthening) on LowStrength Masonry Buildings. Athens. TOMAZEVIC M. 1991, The Strengthening of Stone Masonry Walls with Grouting. Ljubljana. TORRACA G. 1988, Porous Building Materials. ICCROM, Rome. WEAVER M. E. 1993, Conserving Buildings. New York.

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Walls strengthen and treatment: the Egyptian experiences

Walls masonry in traditional architecture are generally composed of natural stones or bricks usually connected with mortar. More and more modern technologies have been applied recently to preserve and restore old walls. A lot of institutions and working groups are dealing with the development and application of new technologies in strengthening the traditional buildings. Where traditional techniques are proved inadequate, the consolidation of the building can be achieved by the use of any modern technique for conservation and construction, the efficiency of which has been proved by scientific data and experience. Evaluation of present building condition may be a part of routine inspection and maintenance or could be initiated as a result of unsatisfactory performance, signs of deterioration, or identification of a need for upgrading. The evaluation procedure consists of (Site investigation and data collection - Identification of the structural and non-structural subsystems of the building - Field testing, Laboratory testing - Analysis of the structure - Evaluation of the seismic performance of the building subsystems - Follow-up on-site inspection of accessible and critical subsystems Preparation and production of the final report). The objective of this evaluation procedure is to understand the composition, the condition and the integrity of the structure. For cultural heritage structures, the gathering of information should produce a brief history of the structure, detailing the period and phases of its construction, with dates and details of structural and non-structural changes/repairs that have occurred over its life. Damage means a situation in which the structure has reduced or lost his bearing capacity till reaching, in the extreme conditions, failure and collapse. This situation is usually characterized by cracks, crushing, detachments, permanent deformations, out of plumb. Deterioration or decay is a physiochemical alteration of the material properties that usually induces a reduction of resistance, an increase of brittleness and porosity, loss of material, starting usually from the external surface toward the interior. Origin of damages and deterioration can be related to one or more of the following factors: Risk coming from the original design of the building Building traditions and materials in the construction period Use of a construction beyond its estimated average age Errors and imperfections in the original design Interventions of new environmental and social factors

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Wahid El-Barbary Architect General Director in Sector Projects of the Supreme Council of Antiquities, Egypt

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The structure represents the conceptual part of the construction that on the one hand transforms the actions in stresses, on the other hand provides the strength. The structural behavior depends mainly on the material characteristics, the dimensions, the connections between the different elements and the boundary conditions. The examination of the damage typologies is very important as the deformations, crack pattern etc. are strictly related to the structural behavior and the actions that caused this damage. The visible damage signs, depending on the different types of material and construction, can be assimilated to three categories: Cracks in the materials that do not resist to tensile stresses: this sign is the more frequent in the masonries, that has a very low resistance to tension Crushing of compressed elements: also this phenomenon— even if less frequent, but much more dangerous than the first one—is visible especially on the masonries. The crushing is characterized, depending on the kind of material, by swelling, detachment of flakes, crumbling away... in the initial phase some micro cracks parallel to the direction of the stress appear.

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Permanent deformations: this phenomenon is especially related with the effect of the bending induced by the eccentric loads and horizontal thrusts (arches...); in addition, an important component can be related to the foundations and soil deformations. Into the thick masonries, some buckling phenomena can appear due to the weakness of the connections between the external curtains and the internal nucleus. The critical situation can cause a sudden lateral deflection that is particularly a dangerous phenomenon in the slender elements. The observation, the knowledge of the building history and the interpretation of the structural calculations (referred to possible actions and to the analysis of the consequent cracks pattern), as well as the results of investigations and monitoring systems, give the tools to understand and interpret at the best the phenomena. However, as in medicine, a correct and complete diagnosis can only be obtained if all this amount of information is combined with the intuition, experience and individual capability. The examination of some cases and examples will help to better understand this process and to choose the suitable treatment between using the traditional techniques for strengthening the walls and reinstalling the deteriorated and collapsed parts; or using new techniques for cracks treatment and walls consolidation by injection of traditional materials inside the elements that were weakened by the loss of binding materials; or using tie road to connect between walls using anchors or other materials... Anyway, the decision depends on the analysis of the investigation results which will help to understand and quantify the magnitude and the cause of the problem, the related deficiencies and the emergency of carrying out repair works. The type of remedial work chosen will usually be affected by the unique conditions of the particular building. Beyond ensuring essential structural capacity and correction of other problems that impose an immediate safety hazard, details of remedial measures are often

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Tool 8. Rehabilitation techniques: reinforcing structures Walls strengthen and treatment: the Egyptian experiences

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significantly influenced by financial considerations. Generally, the evaluation and assessment process will lead to one of the following actions: No repair: The safety and performance of the building is adequate. With regular maintenance and perhaps cosmetic improvement, its performance is expected to be satisfactory or at least acceptable for a prescribed period of time. Repair is required: Safety and serviceability problems are sufficiently severe that repair or upgrading is required or can be most effectively performed at this time. Repair is not feasible: The costs of repair largely surpass the benefits. Either demolition of the building is recommended, or, if there are no life-safety issues, the structure is permitted to remain in its degraded condition. Example: Wall stitching using anchor system in monumental building, (Qalawoon complex). Due to the deep cracks in walls, and to avoid rebuilding techniques to fix the problem, the solution comes in an anchorage system. Simply the system consists of a treated stainless steel bars, a sock and grout. First, we make a well-studied design to determine the walls, which must be treated by anchor system due to its ethical & historical value, studying the accessibility to stitch the cracked wall and the anchor positions. After finishing the design and calculation sheets, the stitching project begins by drilling holes with the required diameters & the specified length, then assemble the stainless steel bar into the sock, then both of them are inserted in the wall. After insertion, the anchor injection process takes place with a pressure not exceeding more than two bars until the grout comes out of the hole. The idea of the sock is the behavior of the sock with grout; the sock takes the shape of the inner section of the wall & behaves with the wall as one piece. That is for the longitudinal anchors then the consolidation anchors takes place to stitch the two leafs of the wall.

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Seismic improvement and conservation of structural features

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With reference to all the highlighted issues, the improvement of the seismic behaviour in the traditional architecture can be pursued, by preserving its qualities and static, material, constructional features. The principles of conservation may be more easily applied by means of traditional techniques that have been suggested by the historical architecture and the ancient treaties. By the light of the contemporary scientific and cultural debate, the improvement of the global resistance of the building in this way seems to be the more suitable approach to basically preserve the original conception of the masonry. As well, the single building has a proper static configuration that cannot be warped. An architecture where the peculiar construction process is changed can be just considered as formalistic exteriority. This approach can make use of innovative operative tools, namely the Codes of Practice that specify and describe in detail the general dispositions in relation to the local construction realities. The Codes of Practice, methodologically similar to the Handbooks of Refurbishment, beyond gathering vulnerability analysis for the reference building, propose a series of controls, examples of structural details, solutions conformable with the original constructive building features. However, all these contents have to be interpreted by the planner in relation to the specific situation. The consequent intervention is certainly adequate, as it does not change the “proper logic” (formal, spatial, material) of the existing building and if it is congruent with the “modal logic” (in other words, the process) that it pursues. Besides, recent earthquakes have shown that some structural techniques, frequently applied over the last decades, are not effective. For instance, the reconstruction of reinforced concrete roofs, the insertion of too rigid beams at the top of the walls, the employment of reinforced perforations rather than metal tie beams, have often caused damages more dramatic than the original ones. By the way, the employment of innovative techniques has not to be precluded, in order to achieve the seismic improvement and to preserve the original features and behaviour of the historical buildings, since modern materials and techniques may be more suitable and less intrusive than traditional ones. For instance, the Fiber Reinforced Polymers (FRP) show evident advantages for these purposes: they use small quantity of material, in terms of thickness and weight, they are removable and easy to apply and they don’t change the original behaviour of the structures, as they work after the tensile resistance of the element has been exceeded. By the way, some drawbacks have to

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Giambattista De Tommasi Engineer Full professor in Building Refurbishment (Technical University of Bari), Italy Collaborators: research group work (Fabio Fatiguso, Mariella De Fino and Albina Scioti)

Application of Fibre Reinforced Plastics (FRP): restraint of compressed elements

Reinforcements of vaults by FRP


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be underlined, so that new researches are necessary in this field in order to verify the long term behaviour of these materials and technologies, beyond the interesting results achieved at moment. So, the developed issues highlight that the improvement of the seismic behaviour for the historical traditional architecture has to represent the optimum synthesis, rather than the compromise between the safety and the conservation. The approach has to focus upon the individuation of the weak elements in relation to the Rule of Art, the definition of the collapse mechanisms and the conservation project, strictly aimed at correcting the structural lacks. However, providing the building with suitable seismic resistance characteristics, most of all by ensuring box behaviour, is the global expected result. With reference to the structural techniques in the Mediterranean area, some specific restoration works can be exemplified that are able to ensure a good comprehensive static quality. They basically care the features of the walls and the connections of the load bearing walls with the other ones, as well as with the floors. They use both traditional solutions and, if necessary, innovative materials and techniques to enhance the structural and static characteristics of the building and to meet new safety requirements imposed by the modern culture. Synthetically, among the traditional solutions there are: restoration of the continuity of the wall texture, by localised repairs and/or “unsew-sew“ techniques improvement of the resistance of the masonry panels to horizontal stresses by the regeneration of the cavities with compatible and effective binder mixtures elimination/reduction of the local masonry weaknesses. The complete closing of chimney flues and niches for this purpose is allowed just if it is strictly necessary and does not change the formal and structural characteristics of the building improvement of the seismic resistance of vertical bosses,

II. Reflection and the Project

cornices and other secondary elements by metal/composite material tie beams and anchorages stiffening of timber floors by the overlap of new floor on the existing one and application of iron crosses and transversal connections. Among the innovative technologies, there are: improvement of the connections between vertical elements and floors by anchorages with metal clamps or steel bars between the single beams and the walls elimination/reduction of the drift of arches by metal or fibre reinforced carbon chains top connection by reinforced concrete or reinforced masonry stringcourses or by fibre reinforced carbon belts in order to reduce the possible drift of the roof, to distribute the induced horizontal stresses and to joint the walls improvement of the connections between the walls by metal chains and local reinforced perforations reduction of the structural loads, especially at the top floors, by the replacement of heavy and rigid elements (for instance, the reinforced concrete roofs realised instead of the original timber roofs). Differently, all the solutions that modify the static behaviour of the building or the values and the arrangement of the loads have to be avoided. Particularly, the increase of the permanent loads (by floors and roofs too heavy and rigid for the below walls), the carrying out of stiffening separators or cavities for lifts or staircases, the laying of new floors by means of local demolition or opening of breaches, weakening the masonries, have to be considered very dangerous. Indeed, such works have been widely realised in recent times, often without any control or by operators who were unaware of

FRP reinforcement of timber beams to increase their bearing capability

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the distinctiveness of the structures. As a consequence, very dramatic risks have been induced, particularly in case of earthquake. The transformation, or even the demolition, of these works would be necessary, within a modern and conscious restoration, without any doubt on the technical benefits that widely counterbalance the costs.

Références ABRAMS, D. P. (1992), Strength and behaviour of unreinforced masonry elements. Proceedings of the tenth World Conference on earthquake engineering, A. A. Balkema, vol. VI : 3475-3480. BATOLI G., BLASI C. (1997), Masonry structures, historical buildings and monuments, chapter 11 of Computer analysis and design of earthquake resistant structures – A handbook (Advances in earthquake engineering, vol. 3), edited by D. E. Beskos & S. A. Anagnostopoulos, p. 563-606, Computational Mechanics Publications. Improvement of timber floor bearing capacity (by use of reinforcing boarding)

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CAROCCI C. (2001), Guidelines for the safety and preservation of historical centres in seismic area, III International Seminar on Structural Analysis of Historical Constructions, University of Minho, Guimarães (Portugal), 7th - 9th Novembre 2001, p. 145-165. DE TOMMASI G., MONACO P., VITONE C., (2003), “A first approach to the load path method on masonry structure behaviour”, in Brebbia, C. A. (Eds.), Structural Studies, Repairs and Maintenance of Heritage Architecture VIII, Wessex Institute of Technology WIT Press, Southampton (UK), ISBN : 1.85312.968.2. GIUFFRÈ A., CAROCCI C. (1996), Vulnerability and mitigation in historical centres in seismic areas. Criteria for the formulation of a Practice Code, Proceedings of the 11th World Conference on Earthquake Engineering, Acapulco, Elsevier Science Ltd. GIUFFRÈ A., CAROCCI C. (1997), Codice di pratica: per la conservazione dei Sassi di Matera, Matera, La Bautta. GIUFFRÈ A., CAROCCI C. (1999), Codice di pratica per la sicurezza e la conservazione del centro storico di Palermo - Laterza, Bari (Italie). KARAESMEN, E., UNAY, A. I., ERKAY, C., BOYACI, N. (1992), Seismic behaviour of old masonry structures, Proceedings of the tenth World Conference on earthquake engineering, A. A. Balkema, vol. VIII : 4531-4536. SHRIVE N. G., SAYED-AHMED E. Y., TILEMAN D. (1997), Creep analysis of clay masonry assemblages. Canadian Journal of Civil Engineering, nº 24, p. 367-379.

Improvement of timber floor bearing capacity (by use of reinforcing concrete slab connected to the wall)

Improvement of the connections between vertical elements and floors by anchorages with metal tie beams

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Reinforcing traditional Algerian structures to resist earth movements

II. Reflection and the Project

Abdelaziz Badjadja Architect Professor in Architecture at the University of Constantine, Algeria

The principal elements that have to stand up to seismic action are bracing elements and structural floors integrated with bearing walls. In fact, the structural unity of the construction has to be guaranteed by the building as a whole. The loads acting on structural elements are: dead load, live load, climatic loads and earthquake loads. The action of these stresses has to be resisted to prevent breakage and distortion. The structural elements resistant to earthquake and, therefore, to horizontal shearing stress are: Masonry bearing walls Pillars of stone, brick or marble Arches and vaults 8 Traditional construction has the advantage of being based principally on the courtyard and symmetry, thereby creating a disalignment between the centre of gravity and the point of application of seismic action or the centre of torsion. As a rule, traditional constructions are designed to have just two levels (ground and first floors). If, for a variety of economic and social reasons, extensions are built, thereby increasing the mass and loads, particularly on the ground floor, the foundations and the materials used in the bearing walls are no longer able to ensure resistance. In consequence, bearing walls often sag in response to the horizontal action of earthquake stress. Traditional structures in Algeria comprise: Vertical elements: bearing walls of thicknesses of over 45 cm and generally mixed (2 to 3 courses of common bricks and a course of dry stone or rubble); stone, brick or marble columns, and cross walls that serve to brace the structure Horizontal elements: comprising the trunks of thuya wood of various dimensions, varying from two to three and a half metres long Resistant elements: timber struts working in both directions, linking common brick arches, forming an integrated structural whole. Since the first earthquakes of the 20th century, various techniques have been used, mainly taking the form of wall ties, joining floor structures and bearing walls using steel ties, a very efficient technique but one that is little used today. This procedure became generalized in all public buildings during the colonial period. After the earthquake of El Asnam (now called Chlef), the need

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8

became apparent to repair joints in bearing walls by injecting cement grout and using a lime-based rendering applied over wire netting and filleting, and encasing the corner masonry when the wall junctions are not built according to the rules of construction. In most cases, recent work to consolidate the structures has chosen to conserve the traditional structure with its timber elements and add a secondary structure of metal bars to integrate the two, thereby creating a new structural floor of foam concrete that is lighter and above all more resistant to horizontal stresses. All the timber struts, necessary to the stability and rigidity of arches in courtyards, galleries and T-shaped rooms have been replaced by round bar steel covered (clad) with wood. The first problem was to find masons and others artisans who were familiar with all the techniques needed to maintain and surgically intervene in old buildings.

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Tool 8. Rehabilitation techniques: reinforcing structures

Restoring traditional timber constructions: the Turkish experience

II. Reflection and the Project

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Tool 8. Rehabilitation techniques: reinforcing structures Restoring traditional timber constructions: the Turkish experience

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II. Reflection and the Project

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Tool 9 Rehabilitation techniques: consolidating materials


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Tool 9 Rehabilitation techniques: consolidating materials


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Tool 9 Rehabilitation techniques: consolidating materials

Renderings: consolidation, restoration or replacement.

II. Reflection and the Project

Patrice Morot-Sir Engineer Technical Director of the École d’Avignon, France

When intervening in a façade, professionals have to address many issues. The following inventory aims to list these points with the objective of offering a preliminary guide to work. Each case calls for a project based on three basic stages: The inventory of state of repair The choice of renovation work The specifications of the intervention The implementation of an intervention project and the contracting of an architect cover these points. The presence of an architect is all the more important if the project envisages modifications and adaptations to the building. Traces of old renderings can be discovered by observation: a coat of rendering over a grainy facing conceals two white-painted undercoats, representing a finish coat.

The inventory of state of repair

9

The renovation of façades is an operation with a twofold aim. To represent the building; the façade presents the visible face of the building and determines the ambition of its owners To protect the walls from water damage by means of rendering and paint.

What rendering? What colour? What lime- or whitewash? 2. Protection of facings: What defects? What materials? What pathologies?

The inventory of the state of repair must, then, respond to these two aspects. 1. The presentation of the facings What building? What modifications? Using descriptive data, it is necessary to determine the type of building to be renovated. The building has probably been the object of prior modifications which have to be determined and evaluated in the light of the planned renovation project. This involves determining the characteristics of the building and the features that comprise its identity and history (if the building has no significant features, observe those surrounding it). It is then a question of completing the building according to the characteristics of the facings of the façade (or façades) which are to be renovated:

Before programming renovation work, it is advisable to diagnose the state of the façades. In the event of total rehabilitation of the building, a technical diagnosis of the overall construction is established beforehand. In the case of simple façade renovation, the apparent defects must be examined and the masonry drilled in order to detect possible points of weakness. Cracks that run through the entire thickness of the wall and bulging effects, often due to thrusting, overloading, flexion of beams or differential settlement, call for major intervention before work starts on the façade. According to the case, the structure must be consolidated by repair to the foundations or the implementation of wall ties, piers or tie rods. The fissures must be analysed according to their dynamic and speed of evolution: a tell-tale (strip of plaster, millimetre gauge) should be placed over cracks detected. If the crack is inactive, an injection of mortar grout will be sufficient to fill it. If movement of the masonry continues, the structure must be consolidated.

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II. Reflection and the Project

Traces of damp and detached rendering require work to remedy the various possible causes: sealing of leaks in pipes, removal of renderings that are too impenetrable (using artificial cement), drainage or seepage of rainwater, etc. Before programming faรงade renovation, tests must be carried out at different points of the faรงade. If the wall sounds hollow, indicating blistering and detachment of the rendering, cleaning of the surface may prove necessary. If the defects are due to damp, it will be sufficient to clean the affected parts and apply smoothing mortar. If the phenomenon is due to poor adherence of the rendering to the support, as a result of insufficient evaporation of the water contained in the walls, the rendering must be totally cleaned away and replaced by a natural lime mortar, which has the advantage of allowing the walls to breathe while waterproofing them. The rendering of the wall in question may be in a good general state of conservation, in which case complete renovation is not

Tool 9 Rehabilitation techniques: consolidating materials Renderings: consolidation, restoration or replacement.

mandatory. It is, nonetheless, advisable to carry out a specific diagnosis: Check the general adherence of rendering to the masonry support by knocking on it with your hand or a small tool. If a large surface sounds hollow, it requires removal and renovation. If it sounds hollow in a localized area, a specific injection should ensure adherence. Check the cohesion of the mortar for powderiness by rubbing the surface hard. If grains of sand roll under your fingers, the rendering should be removed and repaired. If only a localized area is affected, partial repair is possible. Check for the presence of rising damp, both outside and in the interior. If there is rising damp, and if the rendering comprises a hydraulic binder (artificial lime, lime and cement mortar) the rendering must be removed to the height of the damp and

9 Preliminary diagnosis Before undertaking work, it is necessary to gauge the state of health of the building, with attention to the following points:

Roofs

Entrance of water through the roofing, chimney flashing, meeting of gable walls and roofing.

Piping and guttering

Guttering, rainwater pipes, downpipes (possible to conceal them?).

Walls and masonry

Presence of cracks (active or otherwise), sealing up of holes, joints, presence of moss, degradation of stone.

Lower wall

Rainwater header, beneath paving blocks, joints between ground and wall, possible drainage, underground networks.

Wood finishing

Verification of calking

Protection against rodents, pigeons, etc.

Miscellaneous

Possible concealment of mains, high current, individual line and low current

Removal of unused elements (metal brackets, etc.) Cracks that run through the entire thickness of the wall

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Tool 9 Rehabilitation techniques: consolidating materials Renderings: consolidation, restoration or replacement.

replaced by a natural hydraulic lime (NHL), a slight overthickness, or given a differential treatment to turn this repaired stretch into a wall base. Check the type of mortar and finishing treatment. If the binding agent used is very hydraulic (artificial lime, lime and cement mortar) a ready mixed lime wash or mineral paint (AFNOR FDT 30-808 standard) will be preferable. In this case, the colours chosen must resemble the tones of lime wash.

The choice of façade renovation Before drafting a project for the complete renovation of the façade, particularly the rendering, it is advisable to consider the purpose to which the building is to be put and the intended image it is to project. The total renovation of the rendering, lime washing and wood finishes may give the building a new appearance—perhaps too new for the choices that led to the purchase of the building. A modest building only expresses its age and history through the degraded condition of these renderings and paint. The imperfections of the facings—the “patina of time”—are sometimes the only feature giving the building the charm of an old construction. The aim of façade renovation must, then, be to conserve this old appearance, requiring a project that respects this idea. Façade renovation, an operation that today all too often takes the form of a totally new rendering after removal of the existing render, is in fact a more complex operation that should be undertaken gradually. Maintenance: the finishes are in a good state of repair: The woodwork needs a new coat of paint The rendering is well bonded to its support and just the base is damaged to a height of some tens of centimetres. In this case, re-rendering the wall up to a height of 90 cm using lime mortar to create a base, touching up a few points and a diluted lime wash to create a uniform surface will be sufficient to conserve or consolidate the old rendering and its imperfections.

II. Reflection and the Project

Replacement: the finishes do not provide their intended function of protection, the renderings are coming away, there are numerous signs of damp, etc. In this case, the renderings definitively need to be replaced and the causes of damp addressed. Depending on the location of the defect, replacement may be partial, limited for example to the ground floor, the most damaged façade or the whole building if the rendering has ceased to serve its purpose. The decision to undertake total replacement must be a consequence of the diagnosis, not a prior decision. Lime mortar (aerial lime, CL, or natural hydraulic lime, NHL) must be used for old masonry. The binding agent habitually used in both mortar and whitewash was lime. This material is particularly suitable for old constructions due to its mechanical and physical properties: Its soft texture allows the rendering to move with the building without creating cracks, as harder binding agents do, instead developing a large mesh of micro-fissures that are imperceptible to the eye and do not affect impermeability. Its porous structure makes lime mortar impermeable to water but permeable to water vapour. This property allows the evacuation of capillary rise, warmed by the sun, as the rising water is transformed into vapour and evacuated via a breathable wall. These mortars are applied manually to the wall by trowel, and may also be projected by a hand-operated roughcast machine or with projected sand, in which case the facing must be compressed by trowel or float. They can also be applied by machine, in which case admixes must be added to the mortar, with specific doses according to the machine used and the type of mortar; they are generally air entraining agents and plasticizer (check their compatibility with lime mortars). The suitability of using a sprayer will depend on the desired finish; it may be appropriate for finishes smoothed with a trowel or float, but the saving in time is less in the case of rendering that is dashed and then finished using a trowel, and it is always advisable to carry out tests.

The choice of binding agent Conservation/restoration: the finishes are not in a good state of repair, but the aesthetic quality of the facing and the nature of the finishes (sundial, inscriptions, etc.) call for conservation: The techniques to be used are those of conservation, to fix the patina and the action of time, at the same time restoring to the finishes their role of protection, resistance, etc. These techniques are applied by specialists, and the project may envisage a localized intervention of this type that does not necessarily apply to all the facings.

Having decided on the choice of façade renovation, it is then necessary to choose the binding agent. The following parameters will help to narrow down the choice. The nature of the support Old or contemporary walls, limestone rubblework, medium or hard stone, rammed-earth or cob walls are different materials that call for a specific binding agent for the scratch coat.

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Tool 9 Rehabilitation techniques: consolidating materials Renderings: consolidation, restoration or replacement.

II. Reflection and the Project

The desired result: the finish coat Climatic conditions, the timeline for work and the stockpiling system all intervene in the choice of the binding agent. All of these factors must be taken into account when applying the brown coat. Le résultat souhaité, la finition Today, the finish coat of a rendering is always applied with regard for aesthetics. Factors to be considered are the grain of the texture, the colour of the rendering and the presence, if applicable, of mouldings. The combination of these three elements should guide the choice of binding agent. A. Observations on the support: the scratch coat The surface to which the rendering is applied has its own characteristics of bonding, porosity and affinity with water. These characteristics determine the choice of binding agent used to mix the

scratch coat. In the following tables, “non-hydraulic lime” refers to slaked limes and lime putty. The surface to which the rendering is applied has its own characteristics of bonding, porosity and affinity with water. These characteristics determine the choice of binding agent used to mix the scratch coat. In the following tables, “non-hydraulic lime” refers to slaked limes and lime putty. B. Site environment and brown coat or levelling The possibilities of stockpiling lime may dictate the choice. Climate Climate also affects the choice of binding agent. In the event of extreme temperatures or high dry wind, it is preferable to use natural hydraulic rather than non-hydraulic lime, since the former sets faster. The choice of a suitable time for work (spring or autumn) or the implementation of protection (wind break, sheeting, etc.) may make it possible to reverse this choice.

9 Type of support

Stage of work

Soft or medium rubblework masonry

Standard binding agent

Dusting off Wetting

Aerial lime or NHL

Scratch coat Dusting off

Fired clay brick

Wetting

NHL, aerial lime

Scratch coat Dusting off Wetting

Hard stone

Wetting (mist)

OLD BUILDING

Compo (NHL + XHA)

Keying NHL

Scratch coat Dusting off Wetting (mist) Rammed earth, adobe, cob

Slurry

Aerial lime

Scratch coat/Brown coat (Three-coat plaster) Dusting off Wetting (mist) Cob, concealed timber framing

Slurry Drying Scratch coat/Brown coat

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Tool 9 Rehabilitation techniques: consolidating materials Renderings: consolidation, restoration or replacement.

II. Reflection and the Project

The time schedule If the work is to be carried out in a short period of time, use of natural hydraulic lime is preferable to non-hydraulic lime (except in the case of three-coat plaster and mezzo-fresco application). In normal climatic conditions, the setting time between scratch coat, brown coat and finish coat can be halved. The finish coat can be mixed using non-hydraulic lime. The finish coat continues to set after the scaffolding is removed. C. The desired result: the finish coat The main role of the finish coat is to highlight and present the facings. The result is a combination of: The grain of the rendering: the surface may be very smooth or rough (coarse grained surface) The colour: the colour is obtained by lime wash applied while the support is still wet or dry, or simply using exposed aggregate and the binding agent of the mortar

Grain of the rendering

Stage of work

Binding agent

Observations

Aerial or possibly natural hydraulic lime

The choice of natural hydraulic lime may be useful in the case of hard stone or dry joints.

Aerial or natural hydraulic lime

The appearance or grain of the rendering is essentially related to the nature of the aggregate.

Aerial or natural hydraulic lime

Use of a wooden float helps to limit laitance.

Trowelsmoothed rendering

Non-hydraulic lime

Fine-grained sand. Slow setting provides a second chance to compress the rendering.

Retouching float-finished rendering

Non-hydraulic lime

Lime putty can be coloured with pigments.

Repointing

Coarse grained

Trowel-dashed rendering

Fine

Float-finished rendering

Very fine

Moulding: the rendering is simply marked to simulate bonding or presents relief. Dash coats finished with a trowel or broom should be applied onto a previously smoothed brown or finish coat. The dash coat does not ensure a waterproof finish. The colour of renderings is the result of the aggregate/binding agent mix or a lime wash. In the case of coloration using aggregate, it is important to bear in mind that natural hydraulic lime has a slight colour of its own (greyish beige, sometimes with a touch of ochre). Aerial limes are much whiter. The choice of one lime over another can make all the difference to the aggregate and has a direct effect on the colour of the rendering. Very white lime tends to alter a solid colour, but there are no hard and fast rules. A prior test is always advisable. In the case of coloration using lime wash on a dry surface, it may be applied to a rendering of non-hydraulic or natural hydraulic lime. In the case of fresco application, the binding agent of the finish coat should generally be non-hydraulic lime.

Guidelines The first step is always observation Photographic study (including all the faรงades treated, details of framing, quoin stones, details of roofing and base) General approach Contact experts, architects, project manager Draft a project, plans, coloured scale model Choice of intervention On-site work 1. When modifying openings, respect the proportions and general arrangement (a window that is taller than it is wide, etc.). In the case of large openings on the ground floor, a detailed project must be produced, locating the element in the plan of the faรงade. 2. Determination of the main faรงade and drafting of a project in which the finish of the rendering creates a hierarchy. 3. Lime rendering (aerial or natural hydraulic lime) with a coarsegrained finish (dash-trowelled, daubed), trowel- or floatsmoothed, etc. The colour will be that of the mixture of sand and lime. If it is not satisfactory, it can be modified using very watered down milk of lime tinged with ochre and earth.

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4. The main plane of the rendering merges with the framing stones. If this is not the case, the rendering covering part of the stone should be cut back to form a regular frame. 5. The foot of the faรงade can be highlighted by a base in a different colour and/or texture to those of the rendering. It will subsequently be easier to renew the rendering only in the part where it is damaged by rising damp or splashing. 6. The quoin stones will be on view or concealed by the rendering. A false in-and-out bond can be used to highlight the edges of the main faรงade. 7. A whitewash can be used on one or several faรงades, coloured slightly by the addition of yellow ochre or natural sienna. 8. The shutters and doors are painted mainly dark colours (green, brown) or a range of greys. The window frames are all the same colour, lighter or a range of greys. Visible wood is not advisable. 9. The ironwork of the openings is painted the same tone as the woodwork.

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The treatment of damp in traditional architecture

II. Reflection and the Project

Soledad García Morales Doctor of Architecture Technical University of Madrid, Spain

1. Criteria of intervention in damp from the ground The criteria of intervention can be outlined as follows, according to their degree of effectiveness: 1. As a rule of thumb, it is better to try to eliminate the cause or focus of the water, if possible, as in the following cases: a. Damage to municipal mains, which can be confused with problems of capillarity. The best intervention is to locate and repair the damage. b. Rainwater seepage from the pavement, which affects the outer walls of a building surrounded by paving (Fig. 1). This calls for a more appropriate design of the engagement of the pavement and the building, waterproofing the pavement if necessary. c. Pockets of water on the ground which form during heavy rain or flooding. In the absence of drainage, the water stands for a long time. The best solution is to establish a type of drainage that “bursts” the pocket, so that the water can always find its way out. Filling the pocket with concrete is usually ineffective unless the corresponding drainage is implemented 2. In most cases, however, it is not possible to eliminate the source of damp, because the source is rainwater, or the groundwater level, or water in the capillary fringe. In these cases, the correct course of action is to try to avoid contact between the water and the building, at the same time designing a course for the water. It is important to stress that, in general, it is not enough to impede or prevent contact (barrier effect), because water is constantly moving. The most efficient solution is to design a course for it to follow. a. In the case of damp caused by the absorption zone, fed by rain in the proximity, the best solution is to design a route for the water (surface channelling, drainage, etc.) that protects the wall by preventing prolonged contact between the water and the foundations or base. (Figs 2 and 3 show the solution adopted to evacuate rainwater retained in the atrium of the church of Santa Maria in Arévalo in Avila, Spain. Project: Isabel García Muñoz and Soledad García Morales.) Theoretically, the nearer to the surface the water is collected and channelled, the less risk the solution involves, as in this case it is simpler to find a point towards which to conduct it.

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This is possible in those cases where the building is surrounded by paving, and slopes can be clearly established. The drainage channels or trenches built for this purpose should be as far as possible from the façade in question. If the paving is laid over infill or very permeable ground, the channel should be waterproofed to avoid possible seepage to the base or foundations. As a general idea, we have to imagine that water not only flows over paving, it also penetrates through cracks between slabs and footing, and runs beneath them, making it necessary to study each case separately. If it is not possible to collect rainwater on the surface (due to an unpaved or partially paved surround) it will be necessary to construct a perimetric drainage system to collect and channel the water away. In fact, drainage is an artificial underground stream, designed to facilitate the flow of water. This involves considering the following premises: – The drainage system must have a clear outflow point. The depth of the system at this point is the main conditioning factor in the layout of the drain. If there is no possibility of forming a natural outlet for drained water, it may be necessary to include a well (sufficiently large and at a

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distance from the building) from which the water can be pumped out if necessary. If this option is not feasible either, it is best not to build a drainage system. An underground channel or drainpipe needs a slope of at least 2%. In some cases, a smaller gradient (1%) is admissible, but in this case prior thought must be given to periodic cleaning of the pipe, with the construction of inspection traps. A drainage system near an underground wall or foundations must be separated from them by a moisture barrier that is strong enough to stand up to water under pressure. The barrier must cover the entire wall that is under ground, not just the level of the drainage tube. If the foundations are built of irregular coursed rubblework and cannot be waterproofed because of their irregularity, it is advisable to separate the drainage system by means of a waterproofed underground wall parallel to the foundations. Because waterproofing an underground wall prevents it evaporating, in the event of capillary damp in addition to rainwater damp, it will be necessary to construct an independent ventilation cavity, as well as drainage. (See section on the design of ventilation cavities.) The trench dug for the drainage system must be filled in with clean aggregate (gravel and sand) that filters the water to prevent mud or clay being deposited and blocking the tube. It is also available to protect the waterproofing when the aggregate is poured in, to prevent perforation. Protection can take many forms (backing with boards or geotextile fabric, for example). Rather than covering a drainage system with solid paving it is advisable to use a permeable alternative (gravel, for example) or open-jointed paving slabs. b. In the case of rising damp, to prevent the ground coming into contact with the buried wall or foundations, it is advisable to build a ventilation cavity (Fig. 4). The aim of the ventilation cavity is to prevent the building materials coming into contact with the ground, by intercepting capillary suction. However, it must be built according to the following requisites: – The cavity must as far as possible be dry and protected from the entry of rainwater or water from other types of damp (damaged pipes, etc.) – It must in all cases be ventilated. Correct ventilation of a cavity of this kind is not straightforward, because the air has to enter (through a sufficient number of gratings), flow through it and emerge on the other side. Ventilation cavities are, conceptually, like air conditioning conduits, through which it is not always simple to get the air moving without mechanical assistance. If the air in a ventilation cavity is not renewed sufficiently, the evaporated damp from the ground will saturate the air inside it, and when relative humidity

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reaches 100%, condensation will form on the walls (Fig. 5), so that damp once again affects the wall or foundations. If correct ventilation of the cavity cannot be guaranteed, it should not be built. When designing a ventilation cavity, it is important to remember that damp air is less dense than dry air, and therefore tends to rise. This physical principle should be used to position the gratings correctly. Dry air should enter at the bottom and damp air come out at the top. The intake air has to be taken from the exterior and returned to the exterior. Cavities that merely move air from the interior of the building are not effective. Ventilation cavities can be built inside or outside the building, to ventilate walls, footing and foundations, but ventilation must always take place as described above: to the outside. Well-ventilated caves, crypts and basements act as ventilation cavities for the floors above. It is advisable to maintain the openings that exist in them, as originally designed (Fig. 6). Converting a basement into a living space calls for a study of the entire building in order to avoid possible negative repercussions.

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c. Finding a solution to a problem caused by the groundwater level is complicated, because no part of a traditional building is impermeable. To prevent entry of water from the phreatic level, the only solution is recourse to waterproofing construction systems. The sole solution, traditionally used, is to channel part of the phreatic level. The resulting system of channels and trenches (Fig. 7) is the basis of a Mediterranean culture that is skilled in conducting water. There are still examples of these buildings, crisscrossed by networks of channels, cisterns and wells. When remains of channels are uncovered in a building, the wisest course of action is to study the system with a view, as far as possible, to recovering its use. As a rule, what works well at the start continues to give good results. This calls for rigorous archaeological and hydrological studies, but it is an interesting undertaking to recover ethnological and architectural heritage. On some occasions, the only solution is to construct a drainage shaft inside (or preferably outside) the building, and pump water out of it (Fig. 8). 3. It is not always possible to channel water from the ground before it comes into contact with the wall or footing. In this case, the guiding criterion is to try to promote evaporation of these elements: By using renders made with mortars that are highly permeable to vapour By ventilating premises or rooms affected by damp.

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None of these interventions offer a definitive solution, but in some cases they are the only possibility, until new construction techniques become available. The aim is to conserve, to the best of our ability, buildings affected by irresolvable damp, and prior study has to answer questions such as what will happen to the materials when evaporation is accelerated, or where the evaporated water will be evacuated to. We have to avoid the evaporation from one place causing condensation in another. A typical case is ventilation of a cave or crypt: unless the entire building is analysed, damp may condense under the roof or in the vaults, because damp air tends to rise, and could accumulate there.

2. Criteria of intervention in damp caused by hygroscopic condensation As we have seen, this type of damp is produced when the building comprises materials that present abnormal hydric behaviour due to the presence of hygroscopic salts. The reaction of the material to the presence of damp (even in vapour form) is disproportionate: large stains appear, seemingly caused by intense focuses of damp though in some cases there is no more than a little evaporation from damp ground, or sometimes even just vapour in the atmosphere.

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If diagnosis detects that the problem is due to hygroscopic salts, the criteria of intervention are the following: a. a. Check that no focus of damp exists, or is so minor that intervention is not required. b. Next, if the element is of artistic or heritage value, the next step is to try to eliminate surface salts. Restorers are well acquainted with the task of desalination of walls and sculptures. This involves placing cellulose membranes soaked in distilled water on the surface to be restored. The water in the membrane dissolves the surface salts of the element in question, and subsequent evaporation transfers the salts to the paper, on which they dry and crystallize. The dressing may then be easily removed. This process is repeated as often as necessary. This system serves to remove small amounts of salts deposited on the part of the wall nearest the surface. It is a delicate and expensive procedure that requires the intervention of a specialist and ongoing supervision to prevent deterioration of the material. It is therefore not a suitable solution for large surfaces without particular value. c. If desalination is not considered appropriate, the only solution is to eliminate the contaminated materials: chipping away renderings and, sometimes, the bonding mortar in brick masonry. Sometimes the salts are only in the render and, once removed, the damp disappears. If the walls are not rendered,


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but are built of bare brick or stone, only the mortar can be removed, which somewhat improves the appearance of the lesion without completely eliminating it. In some buildings, it is common practice to replace bricks or ashlars with new ones. In this case, hygroscopic damp disappears completely, though this criterion of intervention cannot at present be generalized. d. If none of the above courses of intervention are possible, the stain is there to stay. Ultimately, if the only focus of damp is ambient vapour, the lesion is not important, despite being unsightly. The project and type of building will dictate the most appropriate course of action in each case.

3. Criteria of intervention in damp caused by rainwater seepage If diagnosis reveals this problem, the most correct course is to try to prevent seepage as close as possible to source. This means finding out: Where the water enters The route it takes Why it appears where it does.

The most effective course of action is to verify the first, using the necessary techniques. Solving the problem is not usually difficult because it involves construction: designing an appropriate solution for each case. Through the roof Seepage is normally caused by a poor original design or ageing of the materials used, and intervention must address the specific case. At this point, it is interesting to reflect on the permeable nature of Mediterranean flat and terrace roofs. Their effectiveness lies in layers of mortar that are carefully analysed and selected according to the microclimate with the purpose of rapidly evacuating excess water, at the same time absorbing some of it, which subsequently evaporates and cools the interior ambiance. The water absorbed must never reach the interior facing; experience and construction tradition have established the most appropriate design in each place. The solution will fail if an attempt is made without analysis to convert the traditional flat roof into an impermeable roof by interposing waterproof sheeting or materials with an insufficient absorption coefficient (modern ceramic or encaustic tiles). The change of concept in the functioning of the roof calls for an analysis of its new behaviour, in response to high levels of runoff that did not used to exist. The existence of runoff means

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addressing different issues to those of the traditional roof (joints, meeting with the slope and waterspout, etc.), which do not require as much attention in the permeable roof. Furthermore, the interposition of waterproof sheeting hinders or prevents evaporation, as a result of which the roof ceases to contribute to hygrothermal comfort and may even cause problems of condensation when vapour gets trapped in cold areas. This means that solving damp caused by rainwater seepage requires thorough knowledge of the construction and typology of the building in question. It also calls for a laboratory study of old and modern materials in order to establish their hydric characteristics and make their use compatible with present-day requirements.

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Through walls Some of the criteria for intervention in the roof are also applicable to walls that are subject to the action of rainwater and to the design of the necessary protection elements. The rain that falls on a wall both produces runoff and is absorbed by the materials. The balance between runoff and the amount of water absorbed is a characteristic of different construction solutions and, as in the case of the roof, responds to the practice of many years (or even centuries), adapting construction to the materials available and local climatic factors (Fig. 9). As in the last section, uninformed modification of these practices may lead to failure. It is important to remember that a wall in poor condition is not the same wall that was originally built. For example: rounded edges of ashlars may completely modify the proportion of water absorbed by a wall, in some cases calling for intervention that goes beyond repointing to replacing ashlars or a render. As this text illustrates, an analysis of rainwater in permeable buildings is necessary to a correctly designed solution, and solutions do not admit of “recipe-swapping” or model answers. For us, this difficulty is a source of interest, and its study is a mine of knowledge

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Tool 9 Rehabilitation techniques: consolidating materials

Consolidation of the sandstone monuments of the world heritage site of Petra

II. Reflection and the Project

Ziad Al-Saad Ph.D. in conservation and archaeometry Dean of Faculty of Archaeology and Anthropology of Yarmouk University, Irbid-Jordan Fandi Waked Architect Faculty of Archaeology and Anthropology of Yarmouk University, Irbid-Jordan

1. Abstract The main aim of this research was to evaluate the effectiveness of a number of sandstone consolidants. The methodology of the present research is based on laboratory tests for assessing the extent to which various preservatives meet predetermined requirements. Four types of materials were selected for this study. These are variations of silicic acid esters and silicate based materials. Sandstone samples from the word heritage site of Petra were treated by these consolidants and then tested by a series of standard laboratory tests.

2. Introduction Situated in present-day Jordan and hidden amidst nearly impenetrable mountains to the east of the valley connecting the Gulf of Aqaba and the Dead Sea, stands the ancient city of Petra, one of the world’s most visually stunning archaeological sites with spectacular sandstone monuments. Due to it is high significance Petra was inscribed on the world heritage list on 1985. The signs of decay on the monuments of the world heritage site of Petra, that are cut out from the living rock are numerous and alarming. It is estimated that more than 80% of the elaborately chiselled and decorated façades have been lost forever. Since the days when the Nabataeans left Petra for good, all buildings of the town have decayed and the rock monuments were reintegrated into the cycle of nature and left unprotected to the forces of erosion and dilapidation. The threat of further loss of fabric and irreplaceable architectural detail is imminent and real. Therefore urgent conservation measures should be implemented to curb the deterioration and depletion of this important world cultural heritage. It would be grossly irresponsible to apply any unproved material to masonry of high artistic value and historical importance like Petra. However, such masonry is in the most urgent need for treatment. Therefore, reliable procedures for the rapid evaluation of potential preservatives and consolidants are very essential. A universally applicable preservative or consolidant does not exist. However, with the aid of the pre-testing program, the risk of taking unsuitable measures or products is minimized. Laboratory tests are important because the experiments cannot be carried out with the objects themselves. The scientists must

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Petra (Jordan)

conclude from the simple models to the complex situation on a monument. But the arrangements of the materials on the monument and the response of the materials to the environmental influence are so different that all problems of conservation cannot be anticipated in the laboratory experiment alone without the field test (Snethlage et al, 1990). Therefore, field testing should be run parallel with the laboratory testing program. When one wishes to study a particular problem product to be applied to a certain type of Stone, it is essential to run a series of tests that take in consideration the nature of the stone, its weathering behaviour and the ultimate aim of the conservation process. The tests are carried out on samples of treated in comparison with untreated stone.

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It must be noted that the testing of the conservation methods has an exclusively comparative significance. Above all when we consider the fact that the simulations carried out in the laboratory are only approximations of the natural mechanisms of deterioration. This project is based on designing a test regime that could be effectively used to 'evaluate a series of promising commercially available stone consolidants and preservatives. The aim is to select the suitable material that can be used to protect the threatened and weathered monuments of Petra.

3. Performance Criteria In deciding on the most suitable consolidant for a particular treatment, various factors must be taken into consideration. (Amoroso and Fassina 1983: 244). Based on experience and knowledge accumulated in the past few decades, there is almost a consensus about the requirements that a stone consolidant should fulfill. These are:

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Increase in the cohesive strength of the treated stone. Substantial penetration of the treated stone, accompanied by deposition of the consolidant to the full thickness of the weathered zone of the stone. 3. Absence of deleterious chemical or physical interactions between the consolidant and the stone. 4. Creation of a continuous hardness profile. 5. Low coefficient of thermal expansion. 6. compatibility with the nature of the stone. 7. Water vapor permeability/ water repellency (where applicable). 8. Ease of 'application. 9. User safe and economical (labor and material) 10. Long term effectiveness. (Torraca, 1988:87), (Price, 1975: 352), (Amoroso and Fassina, 1983: 243), (Clifton, 1984: 153-54), (Weber and Zinsmeister, 1990: 54),(Weber, 1980: 379).

Tool 9 Rehabilitation techniques: consolidating materials Consolidation of the sandstone monuments of the world heritage site of Petra

4.2. Laboratory testing program The following laboratory testing methods were applied in this study. 4.2.1- Consolidant uptake value (Depth of penetration) The main aim of this test is to evaluate the penetration properties of a consolidation product. Drill cores with 4.1cm diameter and known weights were used in this test. The consolidants were added to the stone by capillary rise method. The drill cores were placed on the top of sponge saturated with different consolidants. The weight increase and rising height of the consolidant were recorded as a function of time. Reading were taken after 30, 60, 120, 300, 600,1200, 1800,and 2400 seconds. 4.2.2-Capillary water uptake value To carry out water absorption measurements 15 drill cores with 4.1cm diameter of different lengths and known weight were used. The tests were performed according to DIN 52617. Drill cores were treated with the different consolidants by spraying. Some untreated cores were kept as a control. Each test sample was individually placed on top of the water saturated pad to allow water to penetrate from the bottom surface of the samples by capillary suction. After 30, 60, 120, 300, 600, 1800, 2400 and 6000 seconds the level of water and the amount of water sucked up w ere measured and recorded by height and weight increase. 4.2.3-- Water absorption by total immersion Untreated and treated drill cores of the Petra sandstone were immersed in water. The absorption of water represented by the % weight gain was recorded after 10, 30, 60 and after 24 hours. The 10 minutes value, the initial absorption capacity gives insight into

4. Materials and methods 4.1. Consolidants Four commercially available stone consolidants were selected for the purpose of this study. Three of the consolidants are based on silicic acid esters: Wacker OH, Wacker H and Funcosil. The fourth is Befix which is a silicate based material (Remmers: 1995, Sanotec: 1995, Wacker-Chemie: 1995). The materials are either water based or solvent based and were applied with a brush or by spraying to drill cores and cubes of sandstone taken from a quarry in Petra.

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the absorptive behavior of the stone in the initial phase of a rain shower. 4.2.4- Water vapor permeability For performing this test 6 samples were used; from each sample, two slices, about 7 to 10 mm thick, one for dry cup and the other for wet cup, were taken. The test was carried out according to DIN 52615; 4.2.5-Salt crystallization test The test was carried out according to DIN 5211. Five drill cores were used in this test. Treated and untreated samples were immersed in a sodium sulfate solution for 16 hours. The samples were then removed from the solution and heated in an oven for 5 to 7 hours at 110oC. A one time soaking and heating procedure is considered to be one cycle. The specimens were subjected to a series of cycles; after each cycle they were examined visually and weight losses were determined. 4.2.6-- Compressive strength measurements Compressive strength measurements were carried in accordance with DIN 1164. The tested consolidants were applied to duplicate prism specimens of stone, 65x 150 x 25 mm. Duplicate prism specimens of untreated stone were also tested. The compressive strength was measured under a hydraulic press (maximum compression 10 T). (Sattler, L., and Snethlage, R.:1990) 4.2.7-Resistance to Freeze-Thaw Damage This test was done to evaluate the effectiveness of different consolidation treatment to improve frost damage resistant of the

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II. Reflection and the Project

stone. The tests were performed following the methods outlined in procedure A of ASTM method C 666. Samples treated with different Consolidants in addition to a control untreated sample were cycled between -18 oC and 22 oC with a cycle time of 4 hours.

5. Results and Discussion The depths of penetration of solutions of Wacker H, Wacker OH, Funcosil OH, concentrated Befix, 1:1 Befix, 1:3 Befix and 1:6 Befix into the drill cores of the sandstone were found to vary between 57.50 mm and 27.00 mm. The best penetration was achieved by Wacker H followed by Wacker OH. This is mainly due to their low viscosity and due to their low molecular weights. The capillary water uptake values of different samples of the untreated were high and varied. They range from 3.26 to 7.69 kg/m2h0.5. This is mainly due to the difference in the nature of the sandstone which means different porosity and due to the different extent of weathering that the stones suffered. All consolidants have decreased the capillary water absorption to different extents. The calculated water absorption coefficients indicate that the order of reduction of water absorption was: Wacker H =Befix 1:1 > Befix concentrated >Wacker OH > Funcosil OH >Befix l: 3 > Befix 1:6 >untreated. Wacker H imparts its water repellency effect due mainly to its alkoxysilanes component. Alkoxysilanes have the advantage of imparting a degree of water repellency to the stone by virtue of their alkyl group which is methyl group in most cases (Larson.J.H S.:1982). Mixtures of silicic ester and methlyltrialkoxysilane are cross-linked within the stone by a condensation or condensation process to both consolidate the spalling stone surface and protect it by making it water-repellent. Befix is an aqueous solution consisting of organic part and of a reactive silicate part. The reactive silicate part reacts with the dissolved calcium and magnesium ions of the stone surface to form a new, compact and stable silicate compound which with its organic part will impart a hydrophobing effect. From the weight loss with time in the wet cup experiment and the weight increase in the dry cup experiment water vapor diffusion in Kg/m2 was calculated. The untreated sample has a high water vapor permeability which is manifested in its low diffusion resistance coefficient. It is quite evident from the results that the treatment of the stone with the different consolidants brings about a decrease in the permeability of the stone. However the decrease in permeability results from the treatment is not remarkable. The largest decrease in water vapor permeability was caused by treatment with Wacker H (28%) while the lowest decrease was caused by treatment with Funcosil OH (8%). Treatment with Wacker OH and Befix 1:6 caused almost similar decrease with 8% and 10% respectively.

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Tool 9 Rehabilitation techniques: consolidating materials Consolidation of the sandstone monuments of the world heritage site of Petra

Conclusion

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The obtained results show that treatment with Befix provided the greatest increase in compressive strength, while the treatment with Wacker OH provided the smallest increase. However it is quite evident that all the test stone consolidants were effective in increasing the compressive strength of the stone. The increase in the compressive strength of the samples treated with Wacker H, Wacker OH and Funcosil OH is quite comparable. This is because all these consolidants contain silicic acid esters as the reactive components that are responsible for the consolidation of the stone. Silicic acid esters act as a stone consolidants by deposing silica gel, the natural stone binder within the pores of the weathered stone leading to an improvement in its cohesion strength. Befix imparts its consolidation strength by a different mechanism. It is reactive inorganic part reacts with the dissolved calcium and magnesium ions of the weathered stone. This results in the formation of a new stable silicate compounds. The sample treated with Funcosil OH showed the most resistance toward the crystallization of salts. However, it suffered from the development of micro-cracks and powdering. The lowest durability was shown by the sample treated with Wacker OH while the best resistance was shown by the sample treated with Funcosil OH. This result is puzzling as both Wacker OH and Funcosil OH are basically ethyl silicates. However it seems to be that to get comparable results of the two treatments with Wacker OH should be renewed after a certain time.

The obtained results demonstrate that the tested stone consolidants have an acceptable but variable consolidating abilities. There is no constant trend for any of the tested materials. In some of the tests a material may give a very positive result. This does not apply to all of the tests where less positive results are obtained. All the tested consolidants have there positive merits but also the negative ones. It is quite obvious that there is no perfect and universal consolidant which can solve all the problems. For Instance, the consolidants applied as a solvent base solutions (Wacker OH, Wacker H and Funcosil OH) have in general better penetration depth than those applied as an aqueous solutions (Befix). On the other hand using highly volatile and flammable solvents, especially in hot climate, may have a serious negative impacts on the human and environment. In addition, evaporation of the solvents results in bringing to the surface of the stone considerable amount of the consolidant which consequently decreases their effectiveness. The consolidants with hydrophobing effects (Wacker H and Befix) have better abilities to reduce the water uptake of the stone when compared to the other consolidants. These materials on the other hand reduced to slightly larger extent the water vapor permeability of the stone. Considering the examples mentioned above it is evident that an evaluation of the results with respect to the durability of the treatment is very difficult because several factors are influencing each other. The magnitude of a single factor is hardly to be quantified; different performance of the treatment may affect a range from optimized water repellency up to the absorption of the untreated material. The same effects can be caused by stone inhomogenities, the main influence having variations in the distribution of the pore diameters. The main conclusion of this study is that even there is no single stone consolidant which could satisfy and meet all the requirements, applying consolidants to heavily weathered and endangered stone is far much better than doing nothing. This is only true if extreme care is taken to optimize all the variables involved. Every object and material presents peculiar problems which must be faced according to circumstances. This is only can be achieved by the careful design of field testing programs utilizing the results obtained by the laboratory testing programs

References Snethlage, R., Wendler, E., and Sattler, L., The Application of Laboratory Processes and Studies to Real Structures, Proc. Sympo. “ Analytical Methodologies for the Investigation of damaged Stones�, 14-21 Sep., Pavia: Italy, 1990. Amoroso, S., and Fassina, V., Stone decay and conservation, Materials Science Monographs, 11, Amsterdam: Elsevier, 1983.

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II. Reflection and the Project

Price, C. A., The Decay and Preservation of Natural Building Material, Chemistry in Britain, 350-353, 1975, 11(10). Clifton, J. R., Adhesives and Consolidants. Reprint of contributions to the Paris Congress 2-8 September, 1984 (ed. N.S. Brommelle, Elizabeth M. Pye, Perry Smith and Garry Thomson). International Institute for Conservation of Historic and Artistic Works. London, 151-155, 1984. Torraca, G., Porous Materials. Building Materials Science for Architectural Conservation. Third edition, Rome, Italy, 1988. Weber, H. and Zinsmeister, K, Conservation of Natural Stone, Expert Verlag, Ehningen, 53-84, 1990. Weber, H., Stone renovation and consolidation using silicones and silicic esters. Wacker-Chemie Gmbh: Munchen, 385-375, 1980. Remmers, Funcosil Facade Protection and Restoration Systems, Remmers Bauchemie GMBH: Germany, 1995. Sanotec Austria, Innovation, Research and Development for the Protection of the Environment, Special Products for Buildings, Construction, Preservation and Treatment, Sanotec Austria Technical Report, Austria, 1995. Wacker,), Wacker Silicones for Masonry Protection, Wacker-Chemie GmbH: Germany, 1995. Sattler, L., and Snethlage, R., Durability and Stone Consolidation Treatments with

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Silicic Acid Ester, Proc. Sympo. “ Analytical Methodologies for the Investigation of damaged Stones”, 14-21 Sep., Pavia: Italy, 1990.

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Treating and protecting timber

Tool 9 Rehabilitation techniques: consolidating materials

Joaquín Montón Technical architect Professor in the Department of Architectural Technology II, School of Building Construction of Barcelona (Technical University of Catalonia), Spain

As my previous article explains, wood is degraded by the attacks of biotic and abiotic agents that may lead to its complete destruction. Action can however be taken to prevent it. First, we have to analyse the causes of degradation in order to take appropriate action. We also have to consider the characteristics of the wood used, its natural durability, its impregnability by protective products, the position of the timber element (this is considered below in the classes of risk) and, on the basis of this data, we can select the most suitable treatment.

Class of risk

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Before going onto the treatments, I will begin by determining the risk to a timber element in a construction. The concept of class of risk is related to the probability of a timber element, structural or otherwise, being attacked by biotic agents according to its potential or real placement. As damp is fundamental to the majority of biotic attacks, the following classes of risk are listed. Class of risk 1 : no risk of damp. The solid timber element is under cover, protected from the elements and not exposed to damp. In these conditions, wood has a moisture content of less than 20%. There is no risk of attack by fungi and there may occasionally be attacks by termites and larva-cycle insects. Examples: flooring, stairs, doors, structural elements in general that are not close to sources of damp, structures inside buildings. Class of risk 2: Risk of accidental damp. The timber element is under cover and protected from the elements but the moisture content may occasionally rise above 20% in part or all of the element, which would allow fungi to develop. The risk of attack by wood-boring insects is similar to the previous group. Examples: damp timber caused by leaks in drains, leaking roofs and structures of a covered swimming pool with high atmospheric humidity and occasional condensation.

Spraying old timber beams before reinstalling them

Class of risk 4: permanent risk of damp. The timber element is in contact with the ground or with freshwater and therefore exposed to humidification and a permanent moisture content of over 20%, which means permanent risk of rot and termite attacks. Examples: constructions in freshwater and pillars in direct contact with the ground, fences, piles, railway sleepers. Class of risk 5: the structural element is in permanent contact with saltwater. In these circumstances, the moisture content of wood is permanently greater than 20%. There is a risk of attacks by marine biotic agents to the submerged parts and all kinds of biotic attacks in unsubmerged parts with very high moisture levels. Examples: constructions in saltwater, jetties, piles, etc. Natural durability and impregnability

Class of risk 3: Risk of intermittent damp. The structural element is in the open, but not in contact with the ground and subject to frequent humidification, with a moisture content of over 20%. There is a predisposition to rot and attacks of wood-boring insects. Examples: outer door and window frames, bridges and pergolas, street furniture.

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Natural durability is defined as wood’s intrinsic resistance to destructive agents. Some woods are very durable, others are not. Impregnability is a wood’s capacity to allow liquid to penetrate it. Sapwood is far more easily impregnated than heartwood, and some woods are easy to impregnate while others are not.


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Protective products These are products with insecticide and fungicide properties for application to wood, though we might also consider protection from atmospheric agents and fire, among others. Not all cases require the same treatment or product, so it is important to choose the appropriate protective product and method of application. Characteristics of protective products An ideal wood preservative must: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

Be toxic to fungi and insects (insecticide and fungicide) but non-toxic to humans and warm-blooded animals. Have a high residual power and be resistant to washing out, evaporation and sublimation. Be chemically stable for a long period of time. Be easy to find and plentiful on the market. Be safe to handle. Be easy to use. Not be corrosive to metals. Penetrate wood well. Not increase the flammability of wood. Allow painting or varnishing of the wood after its application. Not give off an unpleasant smell. Be colourless to allow the treated wood to conserve its natural colour.

No single preservative combines all of these qualities, making it necessary to choose the most convenient and practical option for each case. Types of protective product Water-borne preservatives. These are mixtures of mineral salts dissolved in water as a vehicle to penetrate wood. Their concentration varies according to the degree of desired protection. The method of application has to ensure in-depth penetration, such as the autoclave. They are applied to wet wood or wet the wood during treatment, requiring subsequent drying, which may produce distortion and splitting. They generally colour wood. Water-dispersible preservatives. These are mixtures of active principles that are not water soluble, to which an emulsifying agent is added to produce an emulsion. The active principles are organic compounds. They are usually applied by means of procedures that produce surface penetration, such as brush and spray treatments and dipping. This is an intermediate product between water-borne preservatives and products containing organic solvent. They are

Surface spraying of thin pieces of wood

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Surface spraying of a structural element

applied to wet wood or wet the wood during the treatment, requiring subsequent drying. Wood treated with water-dispersible preservatives does not as a rule change colour, can be given a finish, is compatible with glues, does not corrode metals or plastics, does not increase its flammability and does not stain the materials it comes into contact with. Organic solvent preservatives. These are synthetic organic compounds that use organic solvent as a vehicle to penetrate wood. These products can be used for both surface and in-depth

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treatments. They penetrate very well and can be applied to both new wood and wood that forms part of a construction, but always dry (less than 20% moisture content). They do not change the colour of wood. Some active principles (DDT, dieldrin, lindane) and organic solvent are environmentally unfriendly and, in some cases, highly toxic. Natural organic preservatives. These are products obtained by distilling coal tar (creosotes) or wood, or pyrolysis. Their characteristics make the most suitable methods of application the hot and cold bath or pressure treatment in autoclave. They are very effective against xylofagous agents due to their high toxicity, have a high power of adherence to wood (giving them a longlasting effect) and do not corrode metals. They smell unpleasant for quite a long time; they stain the surface of wood and do now allow immediate subsequent finishes. Due to their smell and the toxic characteristics of some of their components, their use is forbidden in interiors, though they are highly suitable for woods that need to be in contact with the ground, such as railway sleepers and posts.

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Types of protection from biotic agents The types of wood protection according to the depth of penetration of the product are classified as follows:

Tool 9 Rehabilitation techniques: consolidating materials Treating and protecting timber

Class of risk

Type of protection

1

None (surface treatment recommended)

2

Surface (average treatment recommended)

3

Medium (in-depth treatment recommended) In-depth

4

In-depth

5

In-depth

Types of protective treatment We use the word treatment to refer to the application of a wood protection product using the appropriate procedure in order to prevent it being attacked by agents of degradation (preventive) or to eliminate the agents that have attacked it (curative). The treatments can be applied to wood before using it for construction or when it is already in position, and may be preventive or curative. Preventive treatments Preventive treatments are applied to wet or dry wood, before or after use, to prevent attack by biotic or abiotic destructive agents.

Surface protection is when the average penetration reached by the preservative is 3 mm, with a minimum of 1 mm in any part of the treated surface. The appropriate methods of treatment are brush and spray treatments and dipping. Suitable products are water-dispersible products and those using organic solvents.. Average protection is when the average penetration reached by the preservative is greater than 3 mm in any treated area, but less than 75% of the impregnable volume. The appropriate methods of treatment are immersion and some autoclave treatments. The preservatives used are water-borne salts and preservatives in organic solvent. In-depth protection is when the average penetration reached by the preservative is equal to or greater than 75% of the volume. The methods of application are vacuum and pressure treatment in an autoclave. Most of the systems of application—immersion and autoclave systems—are only suitable for new or replacement wood, or elements that can be dismounted for treatment. In the case of rehabilitation, when dealing with wood already in situ, brush and spray treatments will be the most suitable. If indepth penetration is required, injection treatments, with or without pressure, will be necessary. The table below indicates the type of protection required according to the class of risk.

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Protection used during chemical treatment


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Type of treatment – Method of treatment – Type of preservative Class of risk 1 No contact with the ground Under cover

2 No contact with the ground Under cover

3 No contact with the ground In the open

Exposure to humidification

None

Type of protection

Product

Amount of product applied

Method of application

Not necessary

Recommendable Surface

Organic Water-dispersible

80-120 ml/m2 80-120 ml/m2

Surface

Water-borne

50 g/m2 3.5 kg/m3

Recommendable medium

Organic Water-dispersible

250 ml/m2 250 ml/m2

Water-borne

3,5-10 kg/m3

Dipping autoclave

Double-vacuum product

5-15 kg/m3

Autoclave

3,5-14 kg/m3

Autoclave

25 kg/m3

Autoclave

Occasional

Medium Frequent

Recommendable In-depth

4 In contact with the ground or freshwater

Brush spraying dipping

Water-borne

Double-vacuum Creosote product Permanent

Brush spray dipping

In-depth –

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Water-borne

5 In saltwater

Permanent

In-depth

Wood before use Surface treatment (dipping) Surface treatment (spraying) Surface treatment (brush) In-depth treatment (prolonged immersion) In-depth treatment (double vacuum) In-depth treatment (pressure process in an autoclave) Wood already in use Surface treatment (spraying) Surface treatment (brush) In-depth treatment (pressure injection)

Curative treatments These are specific treatments for new or old woods that have been attacked by wood-eating organisms. Their purpose is to eliminate the aggressive agent (biotic agents), check the damage caused by the agent (abiotic) and protect wood against future attacks.

Water-borne

8-15 kg/m3

Autoclave

8-15 kg/m3

Autoclave

Curative treatments are only applied to timber elements already in place and under attack. Wood in use Surface treatment (spraying) Surface treatment (brush) In-depth treatment (pressure injection)

Specific treatments against biotic agents Anti-fungal treatment. Here we will concentrate on areas of the building where suitable conditions for the development of these attacks are found: areas where there is a risk of damp, especially areas embedded in the walls or in contact with them and with the ground. This requires in-depth curative treatment in the form of injection of a preservative with organic solvent. The source of damp must also be eliminated. Treatment against larva-cycle insects. Those areas where an intense attack is detected must be given in-depth curative

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treatment, by injection. In other areas that may be susceptible to attack, preventive surface treatment will be sufficient. Social insects. Termites. Normally, when treating wood for an attack of termites (Reticulitermes), we will not be able to eliminate the termite nest, which is generally outside the building. We have to therefore try to isolate the building and eliminate the insects that remain inside. This will be more or less difficult, depending on the complexity of the building. First, a chemical barrier has to be created around the perimeter of the building by injecting the insecticide into the ground and the base of the walls. The next step is in-depth treatment, injecting all the timber in the dwelling: pillars, beams, truss, door and window frames, etc. This is a very expensive treatment with an aggressive effect on the timber. A new type of treatment is currently being worked on. It involves putting down cellulose bait treated with a chitin inhibitor. This type of treatment appears to eliminate the termite nest completely. It is less aggressive than the traditional system as it does not require perforating all wooden elements and inserting injection valves every 30 cm.

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In-depth injection treatment with alternate perforations

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Tool 9 Rehabilitation techniques: consolidating materials Treating and protecting timber

Treatments against abiotic agents of degradation Treatments against photo-degradation.This involves the application of varnishes or, preferably, stains. Stains are oil-based products to give an open-pore finish to new or old woods. Their main characteristic is that they do not form a film on the surface of the wood and as a result there is no degradation. They are less effective as insecticides and fungicides than preservative base coats, but they incorporate mineral pigments (metal oxides that resist photo-degradation) to reflect the sun’s ultraviolet rays that damage the wood. Fire-prevention treatments. These may take the form of products that reduce flammability, fire retardants such as ammonium sulphate, borax and others. Another possibility is to coat wood with products such as fire-resistant paints, intumescent coatings, plaster and other materials, with the drawback that they conceal the wood.


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Methods and substances for treating and repairing the wooden elements, the Egyptian experience

II. Reflection and the Project

Wahid El-Barbary Architect General Director in Projects Sector of the Supreme Council of Antiquities, Egypt

The researches that have been done in treating and repairing wooden elements in Egypt are distinguished addition to long field experience in conserving the heritage of this important elements and in determining the methods and the appropriate solutions for their restoration as they were exposed to deterioration and destruction factors like chemical, physical, biological and environmental ones. It’s useful to know the basic principles that Egyptian restorers used in this field and which resulted from the long experience over years: 1. Applying repairing and restoration process only for the elements that need this process and which are exposed to destruction and lost. 2. A detailed study of destruction aspects with accurate documentation for determining destruction type or damage and how it affects the element. 3. Applying the primary experiments for substances use in the treating on a sample from the same wood kind of the historical element. 4. Accurate use of the new chemical substances to ensure that the treated wooden elements will not be harmed again in future. 5. The restorer should have high skill and long experience to be qualified for the restoration and repairing. 6. Using the most high technologies which help for a perfect restoration and treatment. The damages which happen to wooden elements can be summarized in: 1. Rolling or cracking as a direct result of the humidity content change according to the environmental physical changes. 2. Funguses and insects infection. Best methods of treating the rolling and cracking: 1. Mechanical Methods: its effectiveness was proved in case of small thickness woods either decorated by other substances or undecorated. Rolling and cracking in this case represent a lot of danger that threatens the feeding substances and spoiling the colors. These methods need suitable periods of weather conditions to prevent the rolling of the element again in case of exposure to the same environmental conditions that causes rolling in the first time.

2. Chemical Methods: its effectiveness was proved in keeping the humidity amount inside the wooden element in harmony with the humidity amount in the surrounding environment, and this by using melted waxes to stabilize this relative case between the element and its environment. It’s used to strengthen the basic body of the element whether by painting or injection and that by using basic oils which help in lowing humidity amount in wood, but injection operations are more successful than painting in keeping the humidity amount inside the wood roots which are exposed to splitting caused by stresses and strains especially in dry weathers. Polymers (industrials ratings melted in organic compositions) are used too in the walls of the rolling wooden elements cells, such as phenol formaldehyde ratings, which gave the best results in stabilizing the shape of the bending wood, and this is due to its qualities in reaching the depth of the wooden elements. 3. Strengthen the weaken wooden elements: restorers tend to use modern chemical substances for its success in long period to keep the wooden element, but as we mentioned before, there are two ways to strengthen the weak woods: 1. Mechanical way 2. Chemical way Most of the times, it is sufficient to use the chemical ways, but in some cases, the element needs the mechanical way, and that is for increasing the degree of stability and giving the hardness to its body. This depends on the condition of the wooden element.

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Treatment of the wooden elements which are infected with insects: First: Resistance by natural ways: By depending on weather factors to kill the insects activities: 1. Heat 2. Light 3. Humidity 4. Air pressure Second: Resistance by mechanical ways: 1. Using hunting boxes for attracting insects. 2. Building walls and holes in insects paths. 3. Collecting insects eggs by hand. 4. Killing the host upon which the insect depends in its food. Third: Resistance by chemical ways: Considered the best way, by using pesticides with special descriptions which include its continuous effect for a suitable period to overcome insects, and aren’t harmful for the wooden

9

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Tool 9 Rehabilitation techniques: consolidating materials Methods and substances for treating and repairing the wooden elements, the Egyptian experience

element. The use of this method must be at least for two years to ensure the insect exposing in all its growing stages. This chemical way resistance is applied through three techniques: Spray way with special pumps, that is used if it’s hard to use the brush. Flooding way. Steaming way. Treatment of wood infections by funguses: Funguses are affected with humidity, high temperature and light in the surrounding environment. These elements affect its generation degree. Wooden elements could be steamed by using pesticides which divide into: 1. Pesticides which are soluble in water. 2. Pesticides which aren't soluble in water, and these are better to use The used pesticides should have these conditions: 1. High effectiveness and a relative long effect. 2. Easily to reach the cells of tiny insects. 3. Don’t leave traces on the treated wooden element.


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On-site reality

III. The work

José Manuel López Osorio Architect Expert in building rehabilitation, Granada, Spain

“If we wait until we know enough to act with complete certainty, we are condemning ourselves to inaction”. Jean Rostand While it is true that the development of the programme of preliminary studies, the reflection phase and a judicious project are vital to the successful rehabilitation of a traditional building, we must not forget that the real objective of the Rehabimed Guide is to turn the material conservation of traditional Mediterranean architecture into an effective reality. The words of the French scientist and thinker Jean Rostand inevitably suggest the need for action as the only instrument capable of implementing the enormous development of theoretical approaches and interminable debates as to criteria of intervention that do not always achieve the expected objectives. Complex, diverse Mediterranean reality calls for action as the only guarantee that justifies the writing of this method. It is, then, on site that the principles of the Rehabimed Method have to be applied and where it is even more important, if possible, to adopt a realistic, integrative, flexible view of the Method, as all the previous phases and stages undergo their true acid test during on-site work, where it is necessary to absorb and assimilate the incalculable series of unforeseen events that arise in rehabilitation work. This reality becomes even more complex because the aim of this guide is to establish a methodology for intervention in the Mediterranean geographical area, which, despite common historical roots and identities, presents a diverse, changing panorama with cultural and socioeconomic differences that condition processes of intervention. The carrying out of work is subject to the existing materiality and a series of technical, administrative and economic circumstances that produce an uneven sphere of action. Carrying out rehabilitation work in the run-down buildings of Europe’s old towns is not the same as in the tourist centres of the Mediterranean islands, the narrow streets of North Africa’s medinas, villages lost in the Atlas Mountains or the run-down oases of pre-Saharan valleys. We are facing changing circumstances in compact urban settings or scattered buildings in the rural world, where difficult access, the non-existence of qualified labour, problems finding the right construction materials or simply complex bureaucracy are the obstacles to be overcome during the process of rehabilitation work. Furthermore, we cannot forget that much of the rehabilitation, extension and remodelling work that takes place in the Mediterranean basin, particularly in countries in the south and

New popular architecture combines traditional forms and typologies with the new materials now available. La Pobla de Benifassà, Castellón (Spain).

rural environments, are informal interventions that do not usually involve the presence of specialists or have the corresponding administrative authorization. However, these spontaneous interventions, the product of the user’s direct need, also deserve consideration, whether for their capacity to destroy traditional ways and means or for their evocative potential to present the new popular reality challenging the habitual direct relation between the traditional and the popular. This diversity of conditions can upset the linearity of processes established according to principles that are excessively rigid or remote from this constructional or deconstructional reality in traditional architecture. The situation calls for the design of an open strategy that conserves a sufficiently clear, well-defined structure while enabling new incorporations that do not distort the Method’s initial objectives, just as a fishbone maintains its stable form while still being flexible and adapting to the variable conditions of its surroundings. Criteria of intervention and programmes defined in advance tend to be disrupted when subjected to on-site reality. This is the real battlefield where there is no looking back, except to learn from one’s mistakes and try to avoid them in future. Rigorous prior knowledge of the building and of the cultural, legal, technical and socioeconomic reality of each region or country requires hard work to plan a judicious intervention. This section of the Method therefore sets out to define a series of basic concepts that can help us to establish common points of

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departure when undertaking rehabilitation of traditional Mediterranean architecture.

Throughout history, traditional architecture has been carried out without the involvement of architects, constituting the natural spontaneous expression of a people with the need to provide a roof over their heads. Buildings constructed without a project show their natural capacity for transformation when it was necessary to consolidate, remodel or extend in accordance with the programme of needs. The industrial revolution, improved communications and the availability of new materials have opened the range of technical and formal possibilities to local builders, who continue to be responsible for the construction or remodelling of traditional architecture. However, the change in starting conditions, with new structural and typological concepts that are no longer based on local tradition or the principles of economic and social organization, has substantially modified the end result and the image of new popular architecture, which is still the response to the new circumstances of the surroundings despite parting company—probably definitively—with the fundamentals of tradition. The present-day context of traditional architecture in much of the Mediterranean is a manifest conflict between two radically opposed concepts: the developed urban world that finds heritage

values in traditional architecture and the reality of a contemporary rural world that seeks to modernize housing with new forms and materials as a symbol of progress. The reality is that until recently user participation in the construction and rehabilitation of housing was quite normal when producing traditional architecture. It seems necessary that it should continue to be so and that the presence of the direct beneficiary of the intervention, both in the project phase and in the carrying out of work, should be one of the keys to popular architecture. Nonetheless, the traditional forms, colours and materials that are appreciated in a contemporary view of the traditional world are frequently not accepted by their users, who look down on the traditional as being associated with the past, the symbol of underdevelopment they hope to rise above, and whose expectations of housing are closer to conventional urban housing, which they identify with progress. Specifically, this takes the form, for example, of the loss of value for the local population of traditional cobbled paving, normally roughly built with large stones, which are replaced by flat stones for greater convenience and to allow traffic. These valuations on the part of the user contrast with the opinions of the occasional visitor, the tourist or the newcomer, attracted by rural tourism or gentrification in a historical neighbourhood. In many cases these new users becomes residents who consider these epidermic values of architecture to be the seal of authenticity. Conflict is inevitable, and the solution has to steer a course between the different requirements, which will depend on the specific conditions of the place, the heritage or exclusively residential nature of the neighbourhood or rural setting and, in

Popular architecture is characterized by the use of colour and salvaged materials. Barrio de la Chanca, Almería (Spain).

The museified remains of traditional architecture form part of the present-day urban landscape in harmony with the new architecture. Larache (Morocco).

The transformations of traditional architecture and user participation in the rehabilitation of housing

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III. The work

short, on identifying why and for whom we are undertaking rehabilitation. The presence of the architect, responsible since the Modern Movement for solving housing problems, finds in traditional architecture the apparent contradiction of having to order this process. His or her participation in striking a balance between the conservation of values to be preserved while responding to the present-day needs of the occupant and user of traditional architecture is a major challenge. However, the reality in many Mediterranean regions is that the presence of the architect is limited in the processes of construction or rehabilitation of dwellings in popular contexts, where the owner, with the help of a local builder, designs, finances and carries out work without a prior project and, in many cases, without administrative control. Here, the processes of selfconstruction or self-rehabilitation display a higher degree of user participation in the production of housing. The naturalness of these processes and personal involvement in the construction of one’s home are worthy of attention, considering the phenomenon as a reality that deserves to be valued, with, as applicable, the introduction of elements to order and reinforce the phenomenon: the presence of an architect as a professional who can help to redirect the process and the participation of the public administration to co-finance work, provide the necessary economic resources to hire specialists and, in short, improve the quality of the intervention. The standardization of this practice is desirable, not as the implantation of measures to distort its initial values but as a strategy to reinforce them, considering self-rehabilitation as a possible model

in our Mediterranean environment, in heritage contexts with limited socioeconomic conditions. In order to carry out this standardization, the role of an understanding administration that considers these two aspects is once again very important. There are examples in the south of Spain, where the regional government of Andalusia has implemented public programmes of self-construction and rehabilitation of dwellings, financing the necessary materials to carry out the work and hiring of specialists. The experiences carried out have included numerous associated advantages. The user directly manages site work and even contributes his labour, leading to a reduction of costs and greater social profitability of the investment made. This is also useful for future transformation and maintenance work, thanks to the user’s knowledge of the location of structural elements, installations, etc. This practice is normally associated with small-scale work, though in many cases actual needs call for overall interventions affecting a large number of buildings or the rehabilitation of singular buildings. These interventions are habitually promoted by local or state government and involve the initial consequence of hiring a single construction company that is not usually linked to the site of work. In this case, experiences have been directed at obliging the tendering company to hire local residents of the neighbourhood or town as workers on the site. This measure introduces major social benefits, as it provides employment in the place in question and contributes to professional qualification. In return, the local residents offer knowledge of local construction culture and their participation on site is an advantage for subsequent maintenance or repair work. The experiences carried out were not straightforward due to the difficulty of finding workers with the relevant basic training and personal

In countries in the south of the Mediterranean, a new metal door is integrated into popular architecture. In the north of the basin, the traditional wooden door becomes a fossilized object in an open-air museum. High Atlas (Morocco) / Alpujarra (Spain).

The use of a mixture of traditional and Western clothing illustrates the social reality in many regions of the Mediterranean. This combination can also be seen in the architecture. Syria.

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interest. These are, however, initiatives of undeniable interest that deserve to be incentivized.

The agents involved in carrying out rehabilitation work The technical and economic administration of building work always requires the active participation of three main agents: the client or user of the building, the specialists who manage the site and the construction company employed to do the work. However, the singular characteristics of rehabilitation work call for a redefinition of these figures and their forms of interrelation. The owner and user is the person who decides to rehabilitate their dwelling, initially using their own resources. However, rehabilitation normally involves greater technical and economic problems than conventional construction, and certain heritage values tend to affect the population in general rather than just the owner. This gives rise to the appearance of the administration to develop the work, normally establishing measures of protection and contributing economic resources. The presence of this new agent is more obvious in the case of singular buildings or facilities such as public washing places, deposits, mills, etc., where public use and, in many cases, public ownership, clearly calls for the participation of the administration.

Tool 10 The reality of on-site work On-site reality

The technical team, normally comprising architects and specialists, is responsible for drafting the project, overseeing rehabilitation work and economic administration. It plays a vital role in the correct planning and rationalization of the process. However, the different circumstances that converge in the rehabilitation of traditional architecture call for greater efforts on the part of those responsible, who cannot limit their participation to technical aspects of the intervention. They are required to give greater commitment and dedication, since they have to modify their traditional role as distant, unrelated specialists to increasingly become mediators between housing and heritage, between rules and reality, between the private individual or the government body that hires them and the needs of the dwelling’s user. The construction company is responsible for carrying out physical rehabilitation work and has to adapt to the specific characteristics of this kind of project. In these cases, the presence of small local companies, or just a good builder who is familiar with local construction systems and materials, is the best choice if the scale of intervention allows it. However, the loss of traditional trades in most countries in the Mediterranean basin calls for applied research to recover traditional construction systems, making ongoing collaboration with the technical team particularly important. These three figures are not always perfectly defined and completely independent. This can have a noticeable effect on the

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The recovery of public washing places, financed by the regional government, has been carried out using local construction materials and systems. The Alpujarra, Granada (Spain).

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Recovery of the local set paving conserving the traditional technique. AlbayzĂ­n, Granada (Spain).


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management model, substantially conditioning the intervention design, mechanisms of control and the end result. The necessary interaction between the different agents involved is, then, an important issue for consideration, particularly if the public administration is involved in the process, since in some cases this supposes the distancing of the direct beneficiary of intervention. This requires the modification of established roles and a more demanding position for all of them, though one with great ultimate benefits. On other occasions, the difficulty is that the interventions are informal, beyond the control of the administration. This is the case of self-rehabilitation, where the owner of the dwelling, with the help of a local builder, designs, finances and carries out work without the presence of specialists, still a relatively habitual circumstance in some areas of Mediterranean geography and one that is worthy of mention. The public administration as regulator of the process In Mediterranean countries where the economic and management capacity of the public administration is sufficient, the rehabilitation of traditional architecture is usually promoted by the state. Its presence as technical overseer of the process also involves total or partial financing of work. This generally takes place within the framework of programmes to protect or safeguard

III. The work

given urban or rural areas, and the imposition by the administration of specific criteria of intervention. The role of public initiative must be seen as an element to regulate and stabilize a process in which market entropy or private interest could produce imbalances that interfere with the conservation of the values of traditional architecture. However, if public initiative does not respect local singularities, the hoped for results will not always materialize. In some cases, the administration’s interests do not coincide with the real needs of the direct beneficiaries of intervention. These issues are difficult to address by means of general or systematize reflections, calling rather for personalized attention that is difficult to achieve in large-scale rehabilitation interventions. Sadly, many public interventions in historic centres carried out in recent decades have invested their efforts in improving the exterior image of buildings and, with it, the urban image of the district, rather than solving the real needs of their inhabitants. Though this trend is fortunately tending to disappear, many programmes have been carried out to rehabilitate façades or urban elements without paying due heed to the interior of buildings and, therefore, failing to address problems of structure or habitability. In other cases, the initial criterion of recovering a traditional typology, inevitably disrupted by the subdivisions of dwellings, occupation of courtyards and galleries or extensions, 10

Recovery of the construction technique of rammed-earth walls, traditional in the north of the Mediterranean basin. La Peza, Granada (Spain).

The application of a layer of plaster over the timber roof sheathing before laying the tiles is a traditional technique now being recovered by rehabilitation projects. Albayzín, Granada (Spain).

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comes into direct conflict with the spatial requirements of the current users. Another issue to emerge in interventions by the public administration is the difficulty of establishing the dividing line between the case of heritage architecture with values to be conserved and that of an intervention to exclusively solve problems of basic habitability. Normally, there are three government agents involved: one responsible for the conservation of heritage, one responsible for developing public housing and one responsible for social aspects. In traditional architecture, it is difficult to define the dividing line between competences and how to direct the priorities of intervention and available funding, leading to numerous conflicts in past experiences. The public presence must in any case be well received, since in economically active contexts, limited but judiciously directed state investment has proved to act as an incentive to private investment. However, in more limited contexts the intervention ends when government funding dries up, making it ultimately responsible for the commitment to intervention and the end result.

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be brought in, subcontracting local companies with tight profit margins, generally reverting negatively on the quality of work. Another figure introduced by government bodies is the approved company, which has to present specific requirements to be able to work on rehabilitation in a neighbourhood, village or region. The approved company guarantees a minimum level of quality and raises the average standard of interventions, and is required to provide general standardization. This circumstance, necessary but not always possible in certain informal construction sectors, is habitual in small-scale remodelling projects and is widespread in most Mediterranean countries. The approval of companies and, in short, the insistence on improving their technical capacity and economic administration necessarily involves specific programmes to retrain or recycle artisans and workshops or training centres, which are definitely a positive experience that helps to raise the quality of construction companies’ staff.

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The training of specialists and construction companies The most delicate part of intervention in traditional architecture comes with implementation on site, due to the lack of a culture of rehabilitation and the shortage of specialists and qualified labour, which logically affect the quality of finished work. Professionals have to complete their specific training with specialization courses, preferably focusing on site work, where the theoretical conditions of academic training are insufficient to deal with the complexity of rehabilitation. This is necessary in all Mediterranean countries, but particularly so in those in the south, where the number of architects is insufficient to deal with existing demands for the construction of new dwellings. Here, professionals are less interested in rehabilitation work and in those cases where it does exist, in practice it is limited to the restoration of monuments, to the exclusion of traditional architecture. Generally, when the administration takes part in the process, it imposes minimum conditions on specialists involved in rehabilitation. The creation of groups of professionals to draft and direct rehabilitation work has produced satisfactory results and contributes to the specialization of professional activity. Construction companies are required to have specific knowledge of the singular characteristics of the architecture in question. Local companies working in villages in the rural world or historical neighbourhoods are the best choice, due to their knowledge of construction systems, and to the difficulties of storage and access to materials. However, these companies do not normally comply with requisites in the event of the administration being responsible for contracting. Larger firms or those from other contexts tend to

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The production project and site contract establish and define the relations between the developer, the specialists and the construction company intervening on any building site, which acquire singular characteristics in the case of rehabilitation work. The production project must reflect the content of work to be carried out and is a valuable document that has to adjust to the real needs of the intervention. The definition and characteristics of this document are covered in other chapters of this guide, but the project merits further discussion here as regards aspects related to on-site work, as it depends in many aspects on this document’s capacity to respond to unforeseen events that may appear during work. It is indisputable that the best guarantee of the implementation of a project is the degree of closeness to the reality of the intervention. The most efficient strategy is to carry out a comprehensive phase of preliminary studies and diagnosis of the building in order to limit unforeseen events during on-site work. However, this is not always possible due to the difficulty of carrying out analyses, removing renders or false ceilings, etc., in a building that is being lived in by its inhabitants. Another consequence of the above is that detailed knowledge of all the technical and construction solutions and materials present in the building will not be collated until the site-work phase, when partial modification of some of the intended solutions will be necessary. The project will inevitably require modification and must therefore be sufficiently open and flexible to absorb new circumstances. Another requirement is the involvement of the users and their active participation in the drafting of the project. This is often


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The neighbourhood’s buildings are restored using traditional techniques, recovering the original typologies and adapting them to the new needs of contemporary use. The courtyard of the traditional Moorish house has been covered by glass to allow climatization of the space and its incorporation into the home. Albayzín, Granada (Spain).

Testing mortars to obtain the right texture and colour for a traditional render is vital to obtaining the expected results. Granada (Spain).

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limited to a consultation and the exchange of information during the information and diagnosis phase, and to the presentation of the initial plans during the project-drafting phase. However, the difficulty of conveying the language of architecture, normally involving abstract representations such as the floor plan, elevation and section of a volumetric reality, hinders an understanding of the project by its beneficiaries, especially in popular contexts. What effectively happens, then, is that the users perceive the reality of the intervention during the production phase, which is when they ask for modifications to the project. The most usual requirements are related to the finishes and the choice of cladding materials (flooring, tiles, colour of the façade, etc.), habitually during on-site work. This question is of great importance, as its represents the personalization of the dwelling in popular contexts and avoids the homogenization of large-scale interventions that affect large numbers of dwellings and are normally commissioned to a single technical team. In this context, there is a risk of taking excessively standardized decisions at the project phase, a far cry from the decentralized, spontaneous production of popular architecture, which, despite having recourse to a limited range of materials and technical resources, offered personalized solutions. The new range of materials available certainly allows the possibility of singularization, but represents the risk of losing the local character that is one of the values to be conserved. The project must consider these circumstances and offer users various possibilities in the course of work to take part in the choice of materials and the creation of a personal space that is different to that of their neighbours, seeing this as a positive contribution to the final result. Another aspect that may condition changes and modifications during on-site work is the real cost of rehabilitation. The project has to include the bill of quantities, listing all the work to be carried out, the surface area affected and an overall valuation of the intervention. The economic valuation of the different concepts must be realistic, calling for a detailed study of prices in the area and the real circumstances of rehabilitation work in a historical neighbourhood or a rural context, where costs may be increased due to difficulty of access and obtaining different materials and qualified labour. The bill of quantities must be comprehensive but sufficiently flexible to cover all situations. An exact but closed document, with budget items that have excessively low margins, can become a dangerous tool that works against the process rather than helping to order and rationalize it, and it is always preferable to produce a quote with a degree of economic margin. Some experiences in northern Mediterranean countries establish basic price agreements that serve as a reference and must be complied with to receive government grants. These basic price agreements are previously adjusted to market prices, but each situation is different and only the accumulated experience of

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managers, specialists and constructors can produce documents that are able to adapt to the unforeseen events of site work. The second vital document for the correct development of rehabilitation work is the works contract, which establishes the economic relation between the owner and the construction company. This document must be known to the technical team, which will advise the client. This team will also take part in selecting the most suitable bid, as an excessively low quote for rehabilitation work does not necessarily guarantee savings at the end of the day. The contract must specify the time limit for rehabilitation work and the form of payment, normally by certification associated with time periods or phases of work. Another question that must be reflected in the works contract is the possibility of issuing a certificate of completion, which adapts the estimated budget to work actually carried out and details possible deviations from the initial quote. However, if there is too great a difference from the original project and the possibility of extending the budget or, simply, if there have been major technical changes, a modified project may have to be drawn up. The modified project redefines the initial project and incorporates new interventions, as well as carrying out a new valuation. However, in many cases, this document involves partial stoppage of work, a circumstance which is not always possible when working on a dwelling that continues to be partially inhabited or when the occupants are being temporarily rehoused in conditions that are not always acceptable. Liquidation and the modified project should be considered not as deviations from or errors in the original project but as

circumstances that are possible if not desirable in a rehabilitation project, and therefore accepted and incorporated as a normal part of this type of intervention. These documents are particularly important in works covered by the Act on Contracts of Public Administrations applied, with variations, in different Mediterranean countries. Administrative difficulties tend to arise when rigid conditions, normally created for new constructions, are applied to rehabilitation, making it especially necessary to adapt project regulations and the Act on Contracts to the singularity, characteristics and scale of rehabilitation work. Although most countries have an appropriate administrative framework for the above conditions, compliance with these regulations is another matter. The strict application of regulations would bring many rehabilitation projects to a halt, particularly in contexts where mechanisms of this kind are not habitually applied and where the administrative procedures introduced by the northern Mediterranean are applied without sufficient adaptation to southern countries. Another more recent circumstance is that of intervention financed by European and international cooperation programmes, which impose a series of administrative, technical, economic and safety requisites in technical and social contexts where practices of this kind were not hitherto habitual. Independently of these administrative issues, we must not forget that many interventions in traditional architecture are carried out informally and subject to scant control or supervision by the public administration. A technical project or document drafted by a professional who has suitably planned rehabilitation work and a

The wealth of nuances of colour and texture in the walls of traditional construction is an element to be conserved after rehabilitation. Rinc贸n de Ademuz, Valencia (Spain).

The combination of new and traditional materials is one of the distinguishing features of new popular architecture. Alpujarra, Granada (Spain).

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III. The work

Preliminary issues Before on-site work begins, there are various administrative issues to be resolved. Normally, municipal authorities require a building permit, which authorizes the intervention subject to compliance of the production project with urban planning regulations. Authorization is also needed to occupy the public highway or to supply water, electricity and drainage, normally requiring the payment of administrative fees. In the case of intervention in buildings situated in urban or rural complexes affected by heritage or environmental protection laws, the project must be reviewed by the corresponding authority. Protection measures may call for the carrying out of archaeological studies on the site where work is to take place.

The choice of materials, environmental aspects and waste management Traditional architecture did not present environmental problems, since it was one element more in the ecosystem. However, the situation has changed: the adaptation of the building to presentday conditions of use necessarily requires the incorporation of new materials, and changes in social circumstances and production economies, particularly in the rural world, are an added difficulty in the conservation of the traditional model. Historical buildings, and particularly architecture in the rural world, were constructed using materials taken from their immediate surroundings and used practically without being transformed. However, the exhaustion of some natural resources, the disappearance of systems of farming or forestry, and the creation of protected spaces have limited the availability of traditional materials, sometimes making it difficult to find the materials needed for rehabilitation. It is often difficult to obtain stone or aggregate from nearby quarries, which may have been closed down due to low profitability or because they are situated within natural parks and can no longer be worked. In other cases, certain types of wood that were frequently used in traditional architecture are now protected, or it is difficult to find products traditionally used in farming and livestock-keeping, such as straw, reeds, animal excrement, etc. In this situation, it is only possible to use materials of similar characteristics that are also found locally. However, this practice involves a major risk: ease of transport and incomprehensible

The rehabilitation of this traditional dwelling was carried out with particular attention to the use of local construction materials and techniques, recovering the elements that characterize it: the oven and the fireplace. Navapalos, Soria (Spain).

The restoration of the marabout of Sidi Abdellah ben Ali, situated in the ksar of Tamnougalt, has helped to consolidate the local population’s cultural and religious symbols. The Draa Valley (Morocco).

works contract to establish the economic relations between the parties are vital to the correct implementation of work. Striking the balance between what is desirable and what is possible is, in these cases, the only useful strategy for carrying out the regulated process of rehabilitation of traditional architecture. It is, then, necessary to define a changing management model that adapts to the starting conditions of the socioeconomic context where the intervention is carried out, initially establishing basic measures of control that can progressively increase in intensity until the proposed aims are achieved.

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market laws now allow the use of raw materials from other geographical contexts which are, in some cases, beyond regional or national borders. The use of decontextualized local materials is producing an alarming homogenization in traditional construction: Galician slate used in supposedly traditional constructions in the mountains on the Mediterranean coast, or ceramics from the east of Spain in North African constructions are some examples that illustrate the risk of this activity. However, in other cases, their incorporation is inevitable: in pre-Saharan valleys it is no longer possible to use palm beams to construct or rehabilitate buildings, as the palm tree is protected in some regions. Its replacement by eucalyptus is now accepted and forms part of the new traditional architecture, despite not being an autochthonous material. It is always better to use a neutral material, such as a render to cover a wall that should be built of stone, than to use a material unknown to local construction, and it is preferable to accept a degree of transformation in textures and materials that can be integrated than to use traditional materials from other geographical contexts. The best solution, however, is to reuse materials salvaged from the same building or other nearby buildings whose state of conservation calls for a complete renovation and, therefore, dismantling. We find a very representative case in southern Morocco, where an abundant material such as the earth used to build rammed-earth walls was reused to construct a new building on its own ruins. However, there are not enough materials available to systematically reuse them in all cases and it is necessary to establish priorities, normally associated with the rehabilitation of public or especially representative buildings. The difficulty of obtaining appropriate construction materials and therefore recovering the traditional construction system in some cases means a higher economic cost, which is a common argument against it. But this is not always the case; sometimes it simply calls for a little more effort in management or the planning of materials and, in most situations, breaking with the builder’s usual routine. Though it is true that it initially requires a greater investment in time and effort on the part of the person or body in charge of the work or the builder who carries it out, once the use of a traditional material has been relearned it is accepted naturally at no additional cost. Another aspect that requires the transformation of traditional architecture is adaptation to present-day levels of comfort and habitability. This affects the use of new materials that comply with functions of insulation, soundproofing or waterproofing, especially drainage, plumbing and electrical installations, and the implantation of renewable energy technologies. In these cases, it is necessary to avoid the use of materials such as polyvinyl chloride (PVC), polyurethane foams or formaldehyde compounds, which present problems of toxicity and waste

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Adobes drying before being used for construction. Dades Valley (Morocco).

Palm timber beams and boards salvaged from an old construction are stockpiled for use in a new building. Tafilalt (Morocco).

Old and new materials are used in the region’s new constructions. Alpujarra, Granada (Spain).


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treatment. There are more environmental friendly alternative materials, such as polyethylene (PE), polypropylene (PP), rubber, cork and wood. Likewise, the excessive use of cement and steel—universal emblems of progress, though they represent major energy costs in their manufacture—is completely out of keeping with the environment and the consequences are irreparable. The alternatives tend to be more costly or less efficient in structural terms, calling for further research into models based on traditional materials such as earth, ceramics or wood, possibly in constant confrontation with regulations but removed from dogmatic stances that seek to simplify reality. Renewable energies are difficult to integrate into architecture, particularly into a traditional building. This is not however a reason for ruling them out and imaginative ways can be found to incorporate them. The use of new technologies and materials is here to stay, and must be accepted as a way of improving the conditions of habitability of a traditional building. Nonetheless, particular attention should be paid to the bioclimatic characteristics of traditional architecture, a scientific study of which should be promoted with a view to limiting the installation of other technologies, particularly in heating and lighting a building. The final aspect to be considered is the management of waste produced during rehabilitation work as a result of the partial demolition of a building whose materials cannot be salvaged or the waste produced by the new intervention. Efforts must be made to limit the production of waste, especially if it is toxic, and dispose of it appropriately at an authorized dump. This question is directly related to salvaging, which, despite initially involving higher labour costs, allows reuse of the materials and avoids the need for transport to a dump and unnecessary waste production. Reuse creates employment and limits the consumption of raw materials, eliminating production and transport costs, making it a particularly appropriate practice from social and environmental viewpoints. In short, the use of a material, its implementation and environmental cost are not directly related to its market price, which is often considered decisive in whether or not to choose it. However, this value does not include the indirect costs or replacement costs. For the Uruguayan engineer Eladio Dieste, there is a clear difference between financial economy, associated with money, and cosmic economy, which, in his words, represents “being in agreement with the profound order of the world”. This means including as part of the decision-making process a consideration of energy, environmental and social costs, and the loss of the values of traditional culture and symbols of local identification. The disappearance of these values obeys the principle of irreversibility, not cost-profit logics; once lost, they cannot be recovered.

III. The work

There are different approaches to this reflection, however, according to the economic context in question. In northern Mediterranean countries, developed economies can and must assume the indirect costs of materials, which have a smaller repercussion on the end price than labour, which is more expensive. However, the reality in other Mediterranean countries is quite different, normally more dependent on imported materials and technologies, proportionally more expensive than labour. Recovering and implementing traditional construction systems The heritage qualities of traditional architecture respond to specific singularities associated with a region, a valley or a village, the value of which is of a quite different order. Traditionally, knowledge of the construction system and the appropriate use of the material were the local builder’s heritage. In many Mediterranean regions, this intangible knowledge has either disappeared or is in the process of doing so, due to the loss of value of local singularity and traditional trades. However, it can still be seen in the existing materiality of those buildings that are least changed, even if it is not valued—or even identified—by today’s local population. A good observer of traditional architecture who can identify the characteristic way of building eaves, the particular bonding of a stone wall or the construction system used in a floor structure will be capable of distinguishing and valuing the local specificities of traditional construction. This appreciation is only possible on the basis of overall experience and a systematic knowledge of different traditional architectures in different geographical contexts. Evidently, once the local construction tradition has disappeared, the recovery of the traditional model is the responsibility of the initiated researcher or the technical team in charge of the intervention. However, theoretical knowledge of the technique is not sufficient for its implementation in the recovery of traditional architecture, which requires practical knowledge and the participation of the constructor. If we were to compare the conservation of materiality using techniques borrowed from the field of monumental restoration (the direct inheritance of material culture) with the real recovery of the traditional construction trade, the latter would probably be considered of greater value. There are representative examples to show that the conservation of materiality is necessary but, in general, the poor condition or ageing of the materials used in traditional architecture and the high economic cost of their strict restoration call for an unprejudiced intervention, considering that the true value of this architecture lies more in the knowledge of a technique and the recovery of a trade than in the freezing of a historical structure. We must therefore accept the dismantling and reconstruction of a stone wall or its repair using stone of similar characteristics, seeing

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this intervention as a natural regeneration of the masonry requiring new elements without losing its authenticity. This makes rigorous knowledge of local construction techniques particularly important in order to avoid the simplifications and regional homogenization that present traditional architecture as a historical falsity. This calls for a new concept: an understanding of the building as a changing element that has undergone numerous interventions in the course of its history and manifests itself as a sum total of construction sequences. Our intervention, then, must be seen as part of the living process of the building that is not afraid of being visible, without necessarily incorporating new materials or new spatial or formal concepts. Repairing an existing wall, which continues to fulfil the same function in the building, is not the same as extending it upwards to create a new floor or lengthwise to occupy part of an empty plot. However, it seems obvious that mere knowledge of the technique and the use of the material, once relearned by the builder, are not sufficient to ensure criteria in the intervention; this also requires conceptual clarity. This sometimes emerges during on-site work, as it normally takes the form of slight nuances that can only be addressed by physical construction: a detailed study of the contacts between masonries when a traditional construction is extended or conservation of the different heights in the eaves of a roof in a converted building. Changes of render that express time sequences by means of slight differences in colour or texture produced by the proportion of mortars or the type of sand or render chosen can also illustrate the transformations of a building in the course of its history or manifest the latest intervention. All too frequently, an ambitious restoration project causes the traditional building to lose many of the nuances that characterized it, becoming so regular as to remove all distinguishing marks. In

Rammed-earth walls are a living construction technique in the region. The AntiAtlas (Morocco).

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this respect, the presence on site of specialists and a comprehensive control of tasks, however insignificant they may seem, is essential to the conservation of these values. The organization of tasks The organization of site work with time schedules and cost charts is vital to any construction project, ensuring the efficient carrying out of tasks and quantifying the economic cost of each phase. A suitable works schedule serves to anticipate supplies of the different materials and availability of the technical and economic resources needed for the successful competition of the intervention. The experience of the builder or construction company in charge of work is an important factor in this type of intervention, since they are responsible both for organizing tasks and meeting standards. However, the inherent difficulty of rehabilitation work, due to unforeseen events, makes it difficult to accurately specify the content and scope of work, and a definite time schedule. The need for partial dismantling, the dependence on materials that are not available on the conventional market and the many tests sometimes needed to decide the judicious course of action all hinder work and require an added effort to keep to the deadlines and budgets laid out in the works schedule. Normally, the standardization of conventional construction is based on the clear separation of the trades intervening, normally


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carried out by companies subcontracted for this purpose. This circumstance, also an aspect of major work on monumental architecture, is not characteristic of traditional architecture, where the scale and the local nature of the intervention allow work to be carried out by a single team of builders who master most of the necessary trades. One direct consequence is greater flexibility in the organization of work, a necessary circumstance when carrying out rehabilitation work. Another aspect conditioning the organization of rehabilitation work, particularly in the case of a traditional building, is the availability of the necessary materials. It is important to be able to plan supplies in advance to ensure that a lack of materials is no obstacle to completion of work. Traditional materials are not industrially manufactured nor, in many cases, are they supplied by a conventional builder’s merchant. It can therefore be difficult to find sufficient homogeneous batches to complete work. The characteristic example is a batch of bricks or tiles that differ in format, colour and texture, either because they are made by artisans or are salvaged from different demolition sites, which have to be combined as they are used to prevent obvious differences. In general, the time factor has a considerable influence on site work. Many projects take much longer than planned, as they require certain climatological or seasonal conditions. For example, because lime mortar takes a long time to set it cannot be used in certain geographical areas during a hard winter, as it does not withstand frost. In other cases, traditional adobe can only be made after the harvest since it requires the fresh straw that increases its strength and prevents retraction as it dries. Another common case is the need for timber that is sufficiently seasoned for use, which, in some cases, requires a period of a year. Another characteristic example is the construction of a rammedearth wall which, being so thick, takes a long time to lose its

Construction of an adobe wall by a local builder, or maalem. Dades Valley (Morocco).

III. The work

moisture content, become lighter in weight and achieve its final strength. The construction of a rammed-earth wall represents a considerable delay, which normally conflicts with the tight timing of a conventional construction site. The finishes of the rehabilitation project also deserve some consideration. The integrity of traditional architecture, in which materials are present with limited transformations, conditions the final image of work, and this means envisaging colours and finishes during the initial phases. A timber beam that is to be stained and darkened has to undergo this treatment and the definitive colour must be decided before it is used. If the treatment is given afterwards, the inevitable seasonal movements of the timber due to changes of humidity will produce colour differences. The singularity of the different tasks has a considerable effect on the established time schedule. A common case is the choice of texture and colour of the mortar used to render a façade, as numerous tests have to be carried out to gauge the effects of combinations of different aggregates and binding agents to achieve the right mortar and finish. The long setting time of traditional mortar and its