Colour and light in the requalification, regeneration and valorisation of residential buildings

Colour and light in the requalification, regeneration and valorisation of residential buildings Pietro ZENNARO, Katia GASPARINI, Alessandro PREMIER Dept. of Design and Planning in Complex Environments, University Iuav of Venice ABSTRACT A PRIN research (Research Program of National Interest) which involved four Italian universities: University of Ferrara, Turin Polytechnic, University of Chieti-Pescara, Iuav University of Venice, has just been completed. The theme of the research concerned the “Requalification, regeneration and valorization of intensive social housing settlements built in the suburbs in the second half of the Twentieth Century”. Within the Venetian Research Unit, the three authors have dealt with the “Environmental quality as result of requalification, regeneration and valorization of the building envelope skin”, focusing their attention on how environmental regeneration is achieved through technological, chromatic and lighting interventions, aimed at improving the last physical frontier of the building.

The case study used as a reference for the test and the validation of the obtained results is a medium-large scale intervention, located in the city of Verona, in Zancle street. The authors carried out on the intervention all the required simulations to verify as the only chromatic and lighting improvement of the last physical frontier of the buildings is capable of generating a significant environmental improvement that reverberates, as well as on the building itself, on the surrounding areas and on the entire neighborhood.

1. INTRODUCTION (P. Zennaro) A good number of European countries have a large architectural heritage that needs to be re-qualified, regenerated and valorized, i.e. brought to an overall condition of adequacy to the current standard of living, issue involving not only Italy. These buildings, some of them once the expression of the most advanced instances of design and construction, today represent the symbol of certain conditions of decay and inefficiency that characterize the contemporary city. To improve their environmental quality, the authors carried out a scientific research that has satisfactorily demonstrated that the most significant interventions from an environmental point of view, obtained by colour and light use, give significant social consequences, taking place around the interface called: architectural envelope.

Here the architectural envelope is not conceived as a functional package, but as an external boundary, in which the technologies that make use of colour and light are capable of ensuring the building quality and ameliorate the environment where it is placed, as well as to provide an adequate protection to the functional layers underneath. Today, this external boundary has considerably evolved: since the skin of buildings has become active, adapting to external environmental conditions, the relationship with the outside and the materials that underlie gave to this external boundary functions that are most similar to an interface than to a passive element which future is degradation and to be destroyed. Today, all the interventions relating to the architectural envelope can produce drastic effects on the improvement of the environmental quality of the entire building and its surroundings:

better energy performances, better environmental and appearance performances, life extension and increased value of the asset.

The effects produced by the requalification, regeneration and valorisation operations on the building envelope are mainly social, economic and environmental. The social effect minimize the discomfort of the inhabitants and could also improve the aesthetic quality get by colour and light solutions; economic effects consist mainly maintaining the existing building, saving time and money; the environmental consequences are focused on the reuse of the building functional parts, involving a small environmental impact and reusing the demolished parts, encouraging recycling, trying to minimize the quantity of material to take to the landfills.

The intervention strategies for the building envelope requalification pivot around the choice of the technical solutions to be adopted. They are derived from the identification of performance deficiencies and inadequacies, closely connected with the existing materials and construction technologies and with the building and the surrounding context history.

The better technical solutions we found during the research are mainly oriented to the cladding, re-cladding, over-cladding and re-sheeting works. But positive effects are only possible if the designer adopts appropriate intervention strategies, directing the project and the execution of the work on goals that make programming and planning the fundamental reasons of the intervention (strategic planning).

2. COLOUR IN HIGH-INTENSITY RESIDENTIAL BUILDING’S ENVELOPES: THE EVOLUTION OF TECHNOLOGIES (K. Gasparini) From the technological point of view the architectural cladding is represented by the finishing last layer of the envelope. In recent years such a layer has increasingly evolved, multiplying the functions, the characteristics and performance. This constructive evolution, typical of many contemporary architectural envelopes, doesn’t match the same result in residential buildings. F. O. Gehry in the eighties of the last century was a pioneer of this new way of design that has now become standard practice in architecture.

Minimal finishing can be found in residential Italian public buildings, built after World War II. They are envelopes where the maximum level of complexity is represented by marble or stone panels, prefabricated panels or plaster or brick finished. In those days the colour of the surface was depending from the type of coating material. The colour of the surface was strictly neutral or of earthy colours. Therefore they were (and still are) suitable for building gray surfaces, such as unpainted concrete prefabricated panels, or with prevalence of colours like marble beige of some local stone used as overcoat the base of the buildings. When the surfaces were plastered the colours range was from all shades of beige to dark brown. Over a time of the seventies of the last century it’s possible to find green variants: from the shade pea green to a moss green, tending to the colour of the vegetation in an advanced state of decomposition.

In this analysis we can easily understand the low level of environmental quality of Italian public housing built at that time. Buildings are still inhabited, often in poor maintenance conditions. In the research carried out were found and filed 25 study cases, made both in Italy and in Europe. The analyzed buildings are distributed among France, Germany, Switzerland and Italy. We analyzed envelopes built after World War II, in which were made works of requalification over the last decade. The research purpose was a

scientific assessment of the type of intervention carried out on the scope of requalification and valorization made by the use of colour and lighting in the external perceived surfaces.

From the research we collected interesting data for the built envelope analysis, both in terms of construction and stratigraphy, and in terms of perception. A specific analysis section is focused on the type of materials used for the cladding, re-cladding, sheeting and over-sheeting. The materials were classified into: traditional, innovative and smart. At this stage the study is focused to analyze in-depth the pattern, the technologies and the consequences of the intervention.

In the analysis of the new envelope the perceptual system has been classified relating to the environment, components and materials used. The analysis of the perceptual system was conducted by a classification of “pattern surface”. This analysis has allowed the split of architectural surface from the point of view of the drawing, of the regularities that are found within a set of observed objects (the pattern identifies a geometric repetition of a graphic pattern on a surface) and of the techniques used to capture the visibility of the facade. The second part of the analysis of the perceptual system took care of the technologies used to emphasize the perception of the facade pattern named “the colour technologies”.

They are distinguished by monochrome or polychrome colours, typical of glassy, plastic and metallic materials. The primary colours are the most common; at most we can find few shades of orange or green, always in deep saturations. It was found, therefore, that the colours and shades, used compared to the situation prior to requalification works, completely change. In certain cases the material itself defines the colour of the facade, in other cases thin films are applied or paints and dyes to get different gradations. These are synthetic colours, resulting from the processes of application of graphic elements obtained by graphics software, which primarily use the colour range of the additive and subtractive synthesis (RGB monitors or four-colour printing: cyan, magenta, yellow, dark).

On the other hand the perception resulting from the use of lighting technology is completely different. In this case the perceptual system is influenced by the use of lamps and / or LEDs. These systems allow more dynamic built envelopes, extending the colour combinations available. Sometimes we can detect the use of mixed technologies, using both the colour and/or the light. In this category, it has been suggested also the application of technologies such as urban-media screens or coatings employing smart systems. These systems are frequently used nowadays for reduction of energy consumption.

3. CHROMATIC TECHNOLOGIES APPLIED TO A CASE STUDY (A. Premier) We chose, as a tool for the validation of the PRIN research, the competition for the environmental requalification of ATER residential buildings of Via Zancle in Verona, built in the Seventies of the Twentieth Century. In the new design intervention, made by the three authors, the traditional solutions have been abandoned in favour of innovative and smart chromatic edge technologies. The set of buildings perfectly belonged to the tradition of Italian post-war neighbourhoods. It was made up of three buildings with the typical services of the neighbourhoods of that time. The buildings were characterized by outer surfaces treated with plaster, subjected to strong degradation. The façades still had the original colours. The external paths were covered with local white stone, often damaged.

The parapets of reinforced concrete bore the signs of an obvious degradation: mould,

peeling, sagging. The vertical elements of the arcades on the ground floor were painted with earthy colours, mostly beige, while the façades, for the first four floors were entirely white. The various overhangs of the buildings (balconies etc..), especially on the upper floors, were painted in beige or red ochre. Beige and ochre were also used to highlight the crowning of the buildings. The metal railings of the balconies were coloured in a faded beige or in a rusty ochre. Even the outer car boxes had the same colours. The buildings were also characterized by a series of changes and accretions accumulated over the years: shutters of different colours, satellite dishes, double windows in anodized aluminium.

Overall, the building features confirmed the result of the research.

With the design competition, the ATER Agency of Verona, owner of the property, wanted to heal all these situations in order to improve the environmental quality of the neighbourhood. The interventions were then concentrated on the outer surfaces of buildings. The building envelope has been upgraded by means of an over-cladding operation with the use of a layered system composed of nano-structured thermal insulation and an outer skin of corrugated aluminium which gave uniformity of colour and pattern to the whole building. The silver colour of the aluminium interacted differently with the sun shading systems provided in the north and south sides. A second layer of glass blades with photovoltaic integration was superimposed to the south façades. The blue colour of the blades draws a pattern that fades towards the upper part of the façade thanks to the convexity of the support structures of the sun screens. The north façade has two different configurations: the daytime mode and night mode. Over the monochromatic aluminium skin there is a metallic fabric that, during the day, blurs the appearance of the façade contributing to a sort of dematerialization of the building envelope. The façade changes completely at dusk. The energy produced by the photovoltaic system is capable of powering a system of LEDs merged into the metal fabric, turning the entire northern façade in a transmitter of messages, images and video in low resolution. The entire façade is tinged with coloured pixels transmitting information that enhance local culture and resources.

In conclusion: the operations of requalification, regeneration and valorisation that are performed on the building’s surfaces, as shown, have an enormous capacity of improvement of the environment even just making a wise (or qualified) use of colour and light.

REFERENCES Zennaro, P., Gasparini, K. and Premier, A., 2012. L’involucro Rivestito. Rimini: Maggioli

Address: Prof. Pietro Zennaro, Dept of Design and Planning in Complex Environments, University Iuav of Venice, Dorsoduro 2206, 30123, Venice, ITALY E-mails: pietro.zennaro@iuav.it, katia.gasparini@iuav.it, alessandro.premier@iuav.it