Manual of Multistorey Timber Construction

HERMANN KAUFMANN STEFAN KRÖTSCH

Edition ∂

STEFAN WINTER

of Multi-Storey Timber Construction

The authors Univ.- Prof. DI Architect Hermann Kaufmann Technical University of Munich, Department of Architecture, Professorship of Architectural Design and Timber Construction Jun.- Prof. Dipl.-Ing. Architect Stefan Krötsch Technical University of Kaiserslautern, Faculty of Architecture, Department of Tectonics in Timber Construction Univ.- Prof. Dr.-Ing. Stefan Winter Technical University of Munich, Department of Civil, Geo and Environ­ mental Engineering, Chair of Timber Structures and Building Construction

This book was compiled under the direction of the Professorship of ­Architectural Design and Timber Construction at the Technical University of Munich, Department of Architecture, www.holz.ar.tum.de Co-authors: Dipl.-Ing. Architect Anne Niemann (Project Manager) Dipl.-Ing. Architect Maren Kohaus Dipl.-Ing. FH MAS ETH MA Lutz Müller Dipl.-Ing. Architect Christian Schühle M. Eng. Dipl.-Ing. Architect Manfred Stieglmeier Research assistants: Dipl.-Ing. Architect David Wolfertstetter M.Sc. Claudia Köhler Student assistants from the Technical University of Munich Tobias Müller, Moritz Rieke, Konstanze Spatzenegger, Fabia Stieglmeier Student assistants from the University of Kaiserslautern Sandra Gressung, Maren Richter, Sascha Ritschel

With specialist contributions from: DI Heinz Ferk Graz University of Technology, Faculty of Civil Engineering, ­Laboratory for Building Science (LFB) at the Laboratory for ­Structural Engineering (LKI) Dipl.-Ing. Sonja Geier Lucerne University of Applied Sciences and Arts – Engineering and Architecture, Competence Center Typology & Planning in ­Architecture (CCTP) Prof. Dr.-Ing. Architect Annette Hafner Ruhr University Bochum, Department of Civil and Environmental Engineering, Chair of Resource-Efficient Building Prof. Dipl.-Ing. Architect Wolfgang Huß Augsburg University of Applied Sciences, Faculty of Architecture and Civil Engineering, Industrialised Construction and Production Technology Dipl.-Ing. Architect Holger König Dipl.-Ing. Architect Frank Lattke BDA DI Daniel Rüdisser Graz University of Technology, Faculty of Civil Engineering, ­Laboratory for Building Science (LFB) at the Laboratory for ­Structural Engineering (LKI) DI Dr. techn. Martin Teibinger Univ.- Prof. Dr. Dr. habil. Drs. h.c. Gerd Wegener TUM Emeritus of Excellence

Editorial services Editing, copy-editing (German edition): Steffi Lenzen (Project Manager), Jana Rackwitz, Daniel Reisch, Eva Schönbrunner, Sophie Karst, Sonja Ratz, Carola Jacob-Ritz Drawings: Ralph Donhauser, Marion Griese, Martin Hämmel, Simon Kramer, Dilara Orujzade, Janele Suntinger Translation into English and copy-editing (English edition): Christina McKenna, Douglas Fox and Meriel Clemett for keiki communication, Berlin Proofreading (English edition): Stefan Widdess, Berlin Production and DTP: Roswitha Siegler, Simone Soesters Reproduction: ludwig:media, Zell am See Printing and binding: Grafisches Centrum Cuno GmbH & Co. KG, Calbe Publisher: Detail Business Information GmbH, Munich www.detail-online.com © 2018 English translation of the 1st German edition ISBN: 978-3-95553-394-6 (Print) ISBN: 978-3-95553-395-3 (E-Book) ISBN: 978-3-95553-396-0 (Bundle) 4

Bibliographic information published by the German National ­Library. The German National Library lists this publication in the Deutsche Nationalbibliografie (German National Bibliography); detailed bibliographic data are available on the Internet at http://dnb.d-nb.de.

This work is subject to copyright. All rights reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, recitation, reuse of illustrations and ­tables, broadcasting, reproduction on microfilm or in other ways and storage in data processing systems. Reproduction of any part of this work in individual cases, too, is only permitted within the limits of the provisions of the valid edition of the copyright law. A charge will be levied. Infringements will be subject to the penalty clauses of the copyright law.

This textbook uses terms applicable at the time of writing and is based on the current state of art, to the best of the author’s and editor’s knowledge and belief. All drawings in this book were made specifically by the publisher. No legal claims can be derived from the contents of this book.

This book is also available in a German-language edition (ISBN 978-3-95553-353-3)

Contents

7 Foreword Part A Introduction 1 2 3 4 5

The development of multi-storey timber construction Wood as a resource Solid wood and wood-based products Life-cycle assessment Interior air quality – the influence of timber construction

10 14 18 24 30

Part B Support structures 1 Structures and support structures 2 Structural components and elements

38 50

Part C Construction 1 Protective functions 2 Thermal insulation for summer 3 The layer structure of building envelopes 4 The layer structure of interior structural components 5 Building technology – some special features of timber construction

72 88 92 114 122

Part D Process 1 Planning 2 Production 3 Prefabrication 4 Solutions for modernising buildings

130 138 142 150

Part E Examples of buildings in detail Joints in detail Project examples 1– 22

160 166

Appendix Authors Glossary DIN standards Literature Image credits Index Supporters / Sponsors

258 260 264 266 268 270 272

5

6

Foreword

Fig. Zollfreilager residential buildings, Zurich (CH) 2016, Rolf Mühlethaler

Timber construction has undergone intensive development in recent years. The quantum leap it has made lately is demonstrated by the fact that a growing number of higher buildings are being built with timber. This classic building material, one that modernity seemed almost to have forgotten, is undergoing a renaissance for various reasons. Climate change is leading to an increasing interest both in the wider public and among architects and their clients in sustainable and bio-based construction solutions that use resources efficiently. Timber construction offers a better response to this interest than other construction methods. Wood’s special tactile, visual and olfactory qualities as a natural building material and its outstanding strength-to-weight ratio make timber construction increasingly attractive in modern construction, although the primary costs compared with common standard solutions can be somewhat higher than those for conventional structures, depending on the type of project. In terms of overall economic efficiency however, modern timber construction can already give conventional construction a run for its money.

This Manual of Multi-Storey Timber Construction is specifically not a continuation or revised version of the Timber Construction Atlas published in 2003. That book focused on timber structural engineering because of the situation that prevailed when it was published. At that time, few multi-storey timber buildings had been built.

The new manual is being published in response to a very different situation. While the use of timber in single detached houses and agricultural construction has been steadily increasing for a long time, it had until recently almost entirely disappeared from cities. This is beginning to change. Initiated by committed housing cooperatives, housing societies and some joint venture residential building projects with a growing awareness of environmental concerns, new multi-storey timber buildings are being built that are making this oldest of natural building materials available for many more people to experience. Timber construction has also begun to make a comeback in cities because it is very suitable for conversion and densification measures in populous urban areas and for

added storeys, extensions and alterations.

Wood is light and easy to work with, can be efficiently transported, and prefabricated elem­ ents can make it possible to build quickly with a minimum of disruption.

The many interesting examples of timber buildings in this manual clearly demonstrate the ways in which they have enriched architecture in urban settings. Many of them are in fact hybrid structures, which is by no means a retrograde step for timber construction. On the contrary, skilfully combining the proven building materials and construction methods that are readily available on the market to build efficient and profitable buildings in keeping with the performance, availability, price and design potential required is both consistent and logic­ a ­ l. This approach has long been typical of ­construction in urban spaces, if we consider the mixture of construction methods used in the Middle Ages, where combinations of timber and stone made it possible to build impressive half-timbered structures, or Wilhelminian buildings, which from the outside seem to be made of solid masonry, but in fact contain a high proportion of timber in horizontal structural ­elements such as slabs and roofs.

It is this wide range of possibilities modern construction offers that has inspired us to question and expand the conventional and very narrow categorisation of timber structures into timber frame and panel construction and solid timber construction. Drawing on standard practice, this book shows the many options for combining horizontal and vertical elements that can make building with timber such a fascinating and creative process. Together with modern shell structures, this is resulting in an almost explosive expansion in the potential applications of this renewable raw material.

Using wood as a construction material also stores carbon for the long term, creating a ­carbon sink and making a positive contribution to combating global warming. Climate change will however impact wood and wood supplies. In future, wood as a natural building material will be available to us in a different mix from that currently prevailing. Supplies of hardwood will probably grow in future, while softwood stocks will simultaneously decline.

This will result in new and further developments

in wood-based materials and a much larger proportion of hardwood-based materials in multi-storey timber buildings than has hitherto been the case, with positive consequences.

Many hardwoods have much better strength and stiffness properties, which can allow planners to work with much thinner and lighter structural components and open up entirely new design possibilities. Europe’s forestry industry, sustainably practised for centuries, shows that despite intensive use of this raw material, a vigorous forest can be maintained that also continues to fulfil its other functions, ranging from air purification through water ­storage up to serving as a recreational space.

Europe currently grows more wood than it uses. In Germany, Austria and Switzerland it would be theoretically possible to build all new buildings with timber using about a third of the annual wood supply.

This manual is designed to provide interested planners and developers who have no or little experience of timber construction with targeted information and to help alleviate their scepticism about a material that is still largely unfamiliar when it comes to constructing multi-storey buildings and subject to various misconceptions. Potential design options are presented and explained based on a new systematisation of construction methods that has been developed based on practical reality. The range of possibilities available shows that building with timber is no more difficult than building with other materials. It is high time to make more use of this readily available natural resource as a material and integrate it more into people’s living and working environments.

We would like to thank everyone who contributed to the creation of this book; the publishers for their confidence in us, the authors for their knowledgeable contributions, the sponsors for their generous support, and our project manager Anne Niemann for her untiring commitment.

Munich, May 2017 Hermann Kaufmann Stefan Krötsch Stefan Winter 7

Part A Introduction

1 The development of multi-storey timber construction Antiquity and the Middle Ages in Eastern Asia The Middle Ages in Europe The modern era 2 Wood as a resource Forestry and timber The forestry and timber industry: ­ partners in timber construction The timber resource situation and its prospects Deciduous woods: another option in timber construction Conclusion

10 10 11 12 14 14 15 15 16 17

3 Solid wood and wood-based products 18 4 Life-cycle assessment Timber buildings can contribute to ­environmental protection Carbon sequestration and substitution Carbon sequestration versus an efficient use of resources in construction CO2-efficient timber construction Comparative evaluations of conventional and timber buildings based on life-cycle assessments Conclusion 5 Interior air quality – the influence of timber construction A healthy indoor climate Emissions in interior air The influence of natural wood on interior air The impact of glued construction timber on interior air The influence of wood-based materials on interior air Strategies for managing emissions Conclusion

24 24 25 25 26 27 28 30 30 30 33 33 33 35 35

Fig. A Illwerke Zentrum Montafon, Vandans (AT) 2013, ­Architekten Hermann Kaufmann

9

The development of multi-storey timber construction

Tō-ji Temple Japan, 888

Pura Besakih Temple Bali, 8th century

Hopperstad stave church Norway, 1130

Qigu Tan China, 1420

“Alter Bau” granary Germany, 1445

57 metres 5 storeys

44 metres 11 storeys

27 metres 4 storeys

25 metres 3 storeys

21 metres 7 storeys

90 m 80 m 70 m 60 m 50 m 40 m 30 m 20 m 10 m

Middle Ages

deal of knowledge and skill involving con­ structional timber preservation that is still in use today.

The lengthening of buildings’ lifespans and structures comprising stacked, well-braced storeys facilitated the construction of multi-­ storey buildings.

The seven-storey former granary (Alter Bau) in Geislingen an der Steige dates from 1445 and is built from timber resting on a masonry basement storey, proof of this construction method’s effectiveness and ­durability (Fig. A 1.6, p. 11).

The modern era Concrete and steel dominated the material canon of classic modernism. Initially, timber as a material for building bearing structures no longer played any significant role. Com­ petition from suddenly widely available, nonflammable materials relegated timber to a

A 1.7

12

building material for lower, sometimes tempor­ ary buildings.

Only since the turn of the millennium has timber construction taken a fundamental new direction, thanks to a series of technical innovations.

In the context of a worldwide political rethink in the face of global environmental development, especially global warming, there has once again been an increased focus on using timber for multi-storey construction in central and northern Europe.

In a wide-ranging model project in Bavaria [1] and following new developments in Austria, a number of three-storey timber apartment houses were built in the 1990s (Fig. A 1.7). ­Initially partly oriented towards North American building methods, these model projects established various construction methods that meet central European requirements. An evalu­ ation of the results of these projects created an impetus for more advanced research by

A 1.8

research institutes and timber construction companies [2].

Technical advances and a continuously improving legislative environment have since resulted in new height records for timber buildings at increasingly short intervals. The sevenstorey e3 apartment building (Fig. A 1.8), built in Berlin in 2008, features elements such as timber-concrete composite slabs and an external steel-reinforced concrete staircase that ensure that it meets fire safety requirements.

Eight-storey buildings such as H8 in Bad Aibling (Fig. A 1.9) and the LifeCycle Tower One in Dornbirn followed in 2011 and 2012. The first timber building taller than eight storeys, the nine-storey Murray Grove Tower, was built in London in 2008 (Fig. A 1.11). A ten-storey apartment building, Forté Tower, opened in Melbourne in 2012. The Via Cenni residential complex in Milan, completed in 2013, (p. 174ff.) is “only” nine storeys high but consists of four residential towers linked by a two-storey plinth

A 1.9

The development of multi-storey timber construction

Damaschke housing estate Germany, 1996

H8 Germany, 2012

Forté Tower Australia, 2012

Student residence Canada, 2017

HoHo timber high-rise building Austria, in the planning stage

9 metres 3 storeys

25 metres 8 storeys

32 metres 10 storeys

63 metres 18 storeys

84 metres 24 storeys

Architects: Fink + Jocher

Architects: Schankula Architekten

Architects: Lendlease

Architects: Acton Ostry Architects

Architects: RLP Rüdiger Lainer + Partner 90 m 80 m 70 m 60 m 50 m 40 m 30 m 20 m 10 m Time A 1.10

Modern era

structure the size of a city block. In the UK, Australia and Italy, the flammability of the ­bearing structure of high-rise buildings is not specifically regulated (as long as an adequate period of fire resistance is ensured), so buildings may be built of enclosed cross laminated timber panels.

A 14-storey building with a glued laminated timber frame, into which prefabricated modular rooms were set, was built in Bergen in Norway in 2015 (Fig. A 1.12). Canada is currently home to the world’s tallest timber building, a student residence in Vancouver completed in 2017 (p. 166ff.). It comprises a glued laminated ­timber frame with 18 storeys over its 63-metre height. This record will however not stand for long because the HoHo, an 84-metre-high ­timber-concrete hybrid high-rise building with 24 storeys is currently being built in Vienna (Fig. A 1.13).

There seems to be no end in sight to these constantly accelerating developments, raising

the question of whether the increasing effort involved makes it worth further pushing the ­limits. What is certain is that timber meets the demands made on a modern building material in all respects. The examples from recent years outlined above show that t­imber’s flammability has long been overstated and is no longer an obstacle to the construction of multi-storey buildings.

Timber now seems to have taken its place in the material canon of current construction and could in future continue its long tradition as a building material for tall and urban buildings.

A 1.11

A 1.12

A 1.7 Apartment building – Bavarian model project, Regensburg (DE) 1996, Fink + Jocher A 1.8 e 3 high-rise apartment block, Berlin (DE) 2008, Kaden Klingbeil Architekten A 1.9 H 8 high-rise apartment block, Bad Aibling (DE) 2011, Schankula Architekten A 1.10 Increases in the heights of multi-storey timber buildings A 1.11 Murray Grove Tower, London (GB) 2008, Waugh Thistleton Architects A 1.12 High-rise apartment block, Bergen (NO) 2015, Artec Arkitekter / Ingeniører A 1.13 HoHo timber high-rise building, Vienna (AT) under construction, RLP Rüdiger Lainer + ­Partner

Notes: [1] Bavarian Ministry of the Interior – Supreme Building Authority (Pub.): Wohnmodelle Bayern – Wohnungen in Holzbauweise. Munich, 2002 [2] For example, see section 1, May – June 2001, Wohnen im Holzstock

A 1.13

13

Part B The support ­structure

1 Structures and support structures From linear member to plane Combining building elements Combining materials Structural planning in timber construction Timber construction compared with other construction methods Conclusion

38 39 41 41

2 Structural components and elements Dowel laminated timber walls Panel construction Cross laminated timber walls Laminated veneer lumber walls Beams Dowel laminated timber ceilings Beam ceilings Box ceilings Cross laminated timber ceilings Laminated veneer lumber ceilings Composite timber-concrete slabs A comparison of timber construction ­elements

50 51 52 54 55 56 57 58 60 62 63 64

44 44 48

66

Abb. B Beech laminated veneer lumber support structure, office building in Augsburg (DE) 2015, l­ attkearchitekten

37

Structural components and elements Stefan Krötsch, Wolfgang Huß

Contemporary timber construction can no longer be accurately represented in terms applicable to more general construction ­methods (see “From linear member to plane” p. 39ff. and “Combining building elements” p. 41).

The building process now customary in timber construction means that current notions of modern timber structures are based around prefabricated wall, ceiling and roof structural elements so the following description of indi-

vidual structural elements and components is limited to those most often used in multi-storey timber construction. Elements are discussed in the context of their different demands on the support structure as vertical (walls) and horizontal (ceilings and roofs) elements and not ordered by material properties depending on individual situations, which makes it easier to compare the various structural elements (see “A comparison of timber construction ­elements”, p. 66ff.).

B 2.1

50

Structural components and elements

Dowel laminated timber walls

B 2.3

B 2.2

Dowel laminated timber structures were initially developed as slab elements. They consist of low-cost, inferior quality boards that are joined to make high-quality, load-bearing solid wood structural components. Continuous connections between several boards compensate for their specific inhomogeneities.

Materials Dowel laminated timber walls consist of solid wood planks, usually softwood, 20 to 60 mm thick, joined together. Storey-high wall elements are usually manufactured in widths that can be easily handled for assembly on site. Boards can run through the entire element, be fingerjointed or have staggered joints. The thickness of the elements is limited only by the maximum board widths and is usually up to 240 mm, or less commonly up to 280 mm.

Originally, individual boards were nailed together, but nails (usually steel) can greatly disrupt subsequent working. If, however, boards are joined with hardwood dowels (usually beechwood), the resulting elements can be worked and recycled like solid wood. Subjecting hardwood dowels to extreme drying causes them to swell up subsequently, so they can be used to create stable, completely adhesivefree connections. Diagonal dowelling makes the form of elements more stable. More recently, boards have increasingly been glued in a manu­facturing process like that used to make glued laminated timber. Dowel laminated timber walls swell and shrink mainly laterally and along the wall with the grain of the board fibres, while in the direction of the wall height they ­retain their form very well.

Surfaces Boards can be planed, rough sawn, sharpedged or chamfered, depending on the relevant design requirements. They may also have various profiles to optimise their airtightness, sound proofing, acoustic properties and cable ducting (especially electronics and computer cables).

Structural functions Dowel laminated timber walls, even slender ones, can absorb very heavy vertical loads

because loads are imposed only in the direction of the wood’s grain. Stacking the boards prevents them from buckling in the direction of their weaker cross-sectional axes. Bonding boards together ensures a homogeneous ­planar distribution of forces and minimises individual weak points. Dowel laminated timber walls are relatively pliant when subjected to horizontal loads along and transverse to the wall unless additional measures are taken to brace them. Wooden composite boards (e.g.

OSB or three-ply panels) attached to one side can brace walls subject to horizontal loads applied in the direction of the wall. Boards can also be joined to a plate with a friction-locked bond to absorb loads applied transverse to the direction of the wall.

Vernagelung Nailing

Verdübelung Dowelling with mit Holzdübeln wooden dowels

Verleimung Gluing B 2.4

B 2.5

Openings Small openings (e.g. through walls for installations) can be made in dowel laminated timber walls without trimmer joists. It may be necessary to add horizontal elements like lintel beams or parapet transoms for larger openings such as those required for windows or doors.

B 2.6

B 2.1 Prefabricating timber wall panels shortly before ­installing the windows B 2.2 Prefabricated dowel laminated timber wall with OSB planking B 2.3 Dowel laminated timber wall element made of ­individual boards B 2.4 Various ways of joining planks: nailing, dowelling with wooden dowels, gluing B 2.5 Profiling of planks to interlock them and improve airtightness and soundproofing B 2.6 Increasing plate rigidity by adding bracing ­planking B 2.7 Improving slab efficiency by joining the board ­layers to the bottom and/or top plate

B 2.7

51

Part C Construction

1 Protective functions Fire protection Protecting timber from moisture Soundproofing and acoustic requirements Timber preservation Thermal insulation in winter and summer 2

Thermal insulation in summer The RIOPT study The influence of structural type Solar radiation and shade Air exchange and natural cooling

72 72 79 82 83 85 88 88 88 90 90

3 The layer structure of building ­ envelopes 92 Requirements for building envelopes 92 Functions of layers of structural components 92 Technical soundproofing aspects 100 Technical aspects of fire safety 101 Further criteria in choosing exterior wall structures 102 Further criteria in positioning layers in horizontal and sloping structural components in building envelopes 103 Polyfunctional layers 106 Jointing principles 106 4 The layer structure of interior structural components The layer structure of timber slabs The layer structure of interior walls Principles of joining interior structural components 5 Building technology – some special ­features of timber construction Planning Prefabrication options The influence of apertures, openings and recesses on the support structure General building physics principles for the integration of building technology Measures for damp rooms Conclusion

114 115 118 120 122 122 122 122 123 126 127

Fig. C 14-storey residential building, Bergen (NO) 2015, ARTEC

71

Protective functions

C 1.21

in the long term does the cell water required by wood-destroying fungi for growth become available.

Timber is defined as dry in this context when it has an average moisture content of ≤ 20 % (DIN 68 800-1, tab. 1). The gap between this figure and the fibre saturation point can be interpreted as a safety margin. If it is not complied with, neither will preventative chemical timber preservation help in the long term. If timber is constantly exposed to moisture, chem­ ical timber preservation will at best delay infest­ ation from destructive fungi, but not prevent it.

Chemical timber preservation is also not necessary to repel wood-destroying insects. Here too, structural measures can effectively prevent infestations. Most insects need to be able to fly freely to lay eggs, which they cannot do in fully insulated structures covered on all sides. It has also been shown that kilndrying timber achieves two things: it kills any insect larvae in green wood and the changes to the timber’s constituents makes it uninteresting to the insects that can infest dried timber.

DIN 68 800-1 defines kiln-dried wood as follows: “Wood that has been dried for at least 48 hours in an appropriate process-controlled technical plant at a temperature of T ≥ 55 °C to a moisture content below 20 %.” [8] Comprehensive investigations of support structures in the past ten years have also shown that, despite the timber at the edges of roofs being freely accessible, no kiln-dried wood showed signs of insect damage.

The minimising of hazardous substances in workplaces and housing and better recycling options for untreated wood are further aspects in favour of a consistent renunciation of chem­ ical timber preservation.

If, however, individual situations occur in which increased hazards from moisture or insects are expected (e.g. thresholds too close to soil, terrace floors or garden and landscaping structural elements that are wholly exposed to weathering or touch the earth), resistant timbers such as larch and Douglas fir heartwood or more resistant types of wood such as oak or chestnut can be used as an alternative to chemical timber preservation agents. Thermally or chemically modified timber can also be used 84

in special cases. So-called “thermowood” is treated under pressure and at specific tempera­ tures to transform its constituents so that it no longer provides nutrients for wood-destroying fungi or insects (Fig. C 1.25 d). The treatment does however cause the wood to change colour (from dark brown to black) and reduces its strength and stiffness. This is also the case with chemically modified timbers, e.g. those treated with acetylation (Fig. C 1.25 b).

For multi-storey timber buildings, the following timber preservation rules can be summarised: • Exclusive use of kiln-dried timber: If woodbased materials such as glued laminated or cross laminated timber or the like are used, the basic materials (lamella, woodchips etc.) are kiln-dried and do not have to be separ­ ately specified.

• Consistent application of structural timber preservation, e.g. with cladding on all sides, complete insulation of structural elements, distance from soil etc. – no possible water deposits and no open hollow moulds or joints etc. [9] • Avoiding the use of exterior structural elem­ ents wholly exposed to the weather: Exceptions may be made for supports made of resistant timbers or cases where protective planks are added. These were once frequently used and can be easily replaced (e.g. cross-grained timber covers for roof beams) [10] • Consistent application of all measures necessary to protect structures from moisture (see “Protecting timber from moisture”, p. 79ff. and “Facades”, below) • Use of resistant types of timber or chemically modified timber where necessary • Avoiding of preventative chemical timber preservation measures Relevant standards / rules

The DIN 68 800 series of standards contains the current rules on preventative structural and chemical timber preservation in Germany.

The main parts regarding the fundamentals and preventative structural timber preservation were republished in 2011 and 2012. A practice-based commentary accompanying the standard (Praxiskommentar Holzschutz) offers

further information [11]. This series of standards classifies timber structural elements in use classes GK 0 to 5. GK 0 stands for ­conditions in which the application of timber preservation agents is not necessary. Part 2 of the standard prescribes the main structural measures defining the specific classifications.

The wall, roof and ceiling and slab structures shown in this book meet these requirements and can be used without preventative chem­ ical timber preservation. The installation of kilndried spruce or pine wood will usually suffice.

Facades

The construction of facades plays a special role in protecting timber and the protection of structures from moisture is directly linked with their facades. If a structure also protects the timber, basically any timber facade a client desires can be built. The following structures provide sufficient protection from moisture for a facade and the timber structures behind it: • Ventilated, or rear-ventilated, curtain wall facades (with vertical battens) with perman­ ent effective protection from the weather, e.g. closed plank cladding, fibre cement boards, suitable composite timber boards or metal sheeting • A cavity wall without ventilation (horizontal battens) with small-format cladding, e.g. slate, shingles, planking In these two cases, the battens will not require preventative chemical timber preservation but should be kiln-dried. Construction of a second water-bearing layer with permeable foils or suitable planking behind the battens is recommended.

• Thermal insulation system with hard foam, mineral fibre or softwood fibre sheeting and plaster, for which a general technical approval (allgemeine bauaufsichtliche Zulassung) is required in Germany.

• Masonry facing shell with a layer of air (d ≥ 40 mm) and insulation and water-draining layers added to the wall.

Timber facades

The desire for a timber facade, especially in multi-storey buildings, raises the issue of maintenance and any necessary or desired col-

Protective functions

C 1.22

C 1.23

oured paints and coatings. Timber facades do not require preventative chemical measures to protect their timber. If structural conditions are complied with (drip edges, no accumulation of water etc.), completely untreated timber can be used here (Fig. C 1.21). The vertical positioning of facade planks has been shown to be better because water drains off in parallel with the timber’s fibres, but horizontal configurations have also proven their worth, as long as they are appropriately constructed. The top layers of sheeting materials such as solid timber boards must always be installed vertically, otherwise inevitable cracking in the top layer in parallel with the timber’s fibres will harbour draining water, which may result in the top layer being destroyed or peeling off.

ing rain. In areas exposed to weathering, the lignin washes out, leaving only the grey to ­silvery shiny cellulose (Fig. C 1.22). Different areas of a facade are exposed to water to ­varying extents, areas under window sills for example, so facades do not usually go grey evenly. To achieve a more even appearance, the facade can be treated in advance with a grey or grey-silver varnish. In areas more exposed to weathering, this will be “used up” and replaced by natural greying, while in areas not exposed to weathering it is retained, so the facade will have a more even appearance.

Colour treatments should be applied to finely sawn surfaces and never to planed surfaces (Figs. C 1.23 and C 1.24). Industrially colourtreated finely sawn surfaces and permeable, ideally not film-forming coatings that allow the small amounts of water that permeate due to inevitable defects to dry out again can last for more than 20 years. The colour coating should, as far as possible, only be applied after facade elements are cut to size, otherwise great care must be taken in treating cut elements. An undercoat and at least one subsequent coating must be applied on all sides to prevent surfaces from absorbing moisture at varying rates.

Rear-ventilated or ventilated areas of exterior wall structures are often exposed to very high

The facade’s appearance and colour treatments for facades

Untreated timber plank or panel facades are usually made of especially robust woods such as larch or Douglas fir. Facades made of untreated timber or thermowood will inevitably change colour over time because the lignin in timber photo-oxidises, making it look almost black and breaking its chemical bond with the rest of the timber structure. This darkens the timber in areas where it is shielded from driv-

C 1.24

levels of relative humidity, although in recent years the mineral-based colours now offered by some manufacturers have proven their effectiveness here.

Thermal insulation in winter and summer In most European countries, the requirements for the annual energy consumption of buildings are prescribed in legislation. The common goal of these laws is to minimise the energy consumed through building operations, with the long-term goal of creating climate-neutral building stocks, so they usually set limits for their annual primary energy consumption for heating, hot water, ventilation and cooling.

Various requirements are made on the per­ formance of building envelopes depending on climate conditions. Their insulation and ­airtightness greatly influence the energy consumed for heating, ventilation and cooling.

The other major factor in this context is user behaviour, which is on the one hand purely individual and on the other hand determined by the overall interior climate. In Germany, the Energy Saving Ordinance (Energieeinsparverordnung – EnEV) [12] prescribes thermal insulation requirements.

a C 1.21 Ideal connection between a windowsill and r­eveal. NINA-huset, Trondheim (NO) 2013, Pir II C 1.22 Influence of slight variations in exposure to water on the colour of timber C 1.23 Dark glazed wooden boards, carpenter's ­workshop near Freising (DE) 2010, Deppisch A ­ rchitekten C 1.24 Timber board facade with a coloured finish, Södra tennis centre, Växjö (SE) 2012, Kent ­Pedersen C 1.25 Modified pinewood with no coating, from left to right: at the outset, after 3, 6, 9, 12 and 18 months of exposure to weather, facing south at 45°, Vienna (AT) a untreated reference timber surface b acetylated timber c timber impregnated with chrome-free salts d thermowood e furfurylated timber

b

c

d

e

C 1.25

85

The layer structure of building envelopes

Solid timber structure with composite thermal ­insulation system

Solid timber structure, rear-ventilated

Solid timber structure (visible inside) rear-ventilated, minimal use of foil

Structural component layer Structural component layer Exterior plaster render 10 mm Mineral wool 180 mm Fire-resistant gypsum plasterboard 12.5 mm (additional airtight layer, optional) Cross laminated timber (with µ = 50; sd = approx. 7 m) 140 mm Fire-resistant gypsum plasterboard 2≈ 18 mm Installation layer, optional

Rear-ventilated facade Planking membrane (liner) (sd ≤ 0.3 m) Mineral wool 180 mm Fire-resistant gypsum plasterboard 18 mm Cross laminated timber (with µ = 50; sd = approx. 7 m) 140 mm Fire-resistant gypsum plasterboard 2≈ 18 mm Installation layer, optional

Possible values ­without installation layer: REI 90/K260 U = 0.152 W/m2K R w, R = 39 dB

Structural component layer Rear-ventilated facade Windproofing, optional Wooden composite board (e.g. cement-bonded particle board) Rock wool lamella insulation 180 mm T ≥ 1,000 °C; t ≥ 40 mm Gypsum fibreboard 15 mm Exposed cross laminated timber (with µ = 50; sd = approx. 7 m) 140 mm

Possible values ­without installation layer: REI 90/K260 U = 0.15 W/m2K R w, R = 40 dB

Possible values: REI 60 U = approx. 0.15 W/m2K R w, R = n. a.

Function

Function

Function

Plaster render system: Protection from the weather, windproofing, exterior fire safety cladding

Protection from weather

Protection from the weather

Windproofing, second water-bearing layer

Windproofing, second water-bearing layer, extra insulation

Load-bearing layer, ­ vapour barrier Airtightness, interior ­fire-resistant lining

Exterior fire safety cladding Load-bearing layer, vapour barrier Airtightness, interior fire-resistant lining

Exterior fire safety cladding Load-bearing layer, vapour barrier, airtight layer, dimensioned to withstand complete burnout (fire safety certificate for the specific building required)

a

b

c

and cables penetrate is possible but requires precise planning and for prefabricated elem­ ents should be carried out in the factory or in strictly controlled conditions as far as possible.

ous top and bottom plates up to a maximum height of three to four storeys, otherwise the subsidence ratio from the lateral loading of top and bottom plates becomes too great (Figs. B 1.11 b and c, p. 44). Higher buildings can be built with timber panel walls using hardwood bottom plates and /or supplementary structural measures.

Loads should be transferred in solid timber walls directly through the end grain so slabs should only partly rest on the walls or be laid on walls with a cantilever. Vertical loads can be transferred through steel structures integrated into slabs or cut-outs filled with grouting (Fig. B 1.11 d, p. 44).

Non-load-bearing walls up to high-rise height must only be fire-retardant (REI 30). Beyond this height, the fire resistance required depends on the specific fire safety concept.

Further criteria in choosing exterior wall structures As well as the requirements made on a building envelope described above, other factors must be considered when choosing an exterior wall structure.

Structural factors

If the building envelope is part of the primary structure relevant to the building’s overall structural integrity, timber panel or solid timber walls consisting of cross laminated timber elements (see “c 13 residential and office building in Berlin”: timber panel rear building, solid timber front building, p. 170ff.) or dowel laminated timber elements (see “Residential and commercial building in Zurich”, p. 178ff.) can be used.

Load-bearing timber panel walls can be installed in a standard structure with continu102

A frame structure with appropriately dimensioned supports that transfer loads directly into the supports below them is the most suit­ able construction method for tall buildings, including those at high-rise height (see ­“Student residence in Vancouver”, p. 166ff.).

Elements that partition spaces in this type of facade will therefore not be load-bearing parts of the building envelope, so fire safety requirements on them will be less stringent (see “Fire protection”, p. 72ff.).

C 3.16

Indoor climate factors

Exposed solid timber structures influence a building’s indoor climate. Wood’s low ­thermal conductivity, relatively high bulk ­density and high specific thermal capacity (c = 2,100 J/kgK) increase thermal inertia, ­making wooden buildings very comfortable in summer (see “Thermal insulation in summer”, p. 87). Cross laminated timber can provide almost three times the storage capacity of ­timber panel walls with comparable U values [10]. Wood’s ability to absorb moisture from interior air and release it again after a certain period balances the humidity of air in rooms and improves the comfort of exposed structural components.

Economic factors

A building envelope’s cost depends not only on the material price of its individual layers but also on the efficiency of manufacturing and assembly processes connected with pre-

The layer structure of building envelopes

Timber panel structure with composite thermal insulation system

Timber panel structure, rear-ventilated

Timber panel structure, rear-ventilated, minimal use of foil

Structural component layer Structural component layer Exterior plaster render 10 mm Rock wool lamella insulation 40 mm T ≥ 1000 °C; t > = 40 mm Fire-resistant gypsum plasterboard 12.5 mm Mineral wool 240 mm Vapour barrier (sd ≥ 2 m) Fire-resistant gypsum plasterboard 2≈ 18 mm Installation layer, optional

Rear-ventilated facade Vapour-permeable planking membrane sd ≤ 0,3 m Fire-resistant gypsum plasterboard 2≈ 18 mm Mineral wool 240 mm Vapour barrier (sd ≥ 2 m) Fire-resistant gypsum plasterboard 2≈ 18 mm Installation layer, optional

Possible values ­without installation layer: REI 60/K260 U = 0.14 W/m2K R w, R = 47 dB

Structural component layer Rear-ventilated facade Windproofing, optional Concealed insulation, wooden composite board (e.g. cement-bonded particle board) Fire-resistant gypsum plasterboard 2≈ 18 mm Mineral thermal insulation 240 mm OSB board (sd = approx. 4 m), airtight 24 mm Fire-resistant gypsum plasterboard 2≈ 18 mm Installation layer, optional

Possible values ­without installation layer: REI 60/K260 U = approx.

0.16 W/m2K R w, R = n. a.

Possible values ­without installation layer: REI 60/K260 U = ­0.165 W/m2K R w, R = 49 dB

Function

Function

Function

Plaster render system: Protection from the weather, windproofing, exterior fire safety cladding

Protection from the weather

Protection from the weather

Windproofing, second water-bearing layer

Windproofing, second water-bearing layer, extra insulation

Vapour barrier Bracing, airtightness, interior fire-resistant lining

Exterior fire-safety cladding Vapour barrier Bracing, airtightness, interior fire-resistant lining

Exterior fire safety cladding Bracing, airtight and vapour-resistant layer Interior fire-resistant lining

a

b

fabrication, so very careful and timely planning is essential. There is considerable potential for rationalisation in the detailing of elem­ ent joints and joints with other structural ­components, for example. An expedient construction and installation process, the degree of elements’ prefabrication and transport options must be coordinated with the construction company in good time. This is usually difficult, especially when working on public buildings, because companies have often not yet been commissioned when the work is planned, due to procurement rules. Alternative procurement processes should be developed here to accommodate prefabrication (see “The planning process”, p. 130ff.), because the ways in which individual timber construction companies work can make it necessary to adapt plans, which can be complex and expensive when planning is already advanced (see “Features of planning a timber building”, p. 130).

the building’s environmental performance that increases with the amount of timber used in it.

Planners need to strike a balance between an efficient use of energy and materials and carbon storage in achieving sustainability and to use all resources, including renewable resources, carefully and sparingly.

Choosing insulation with a view to ecological considerations is becoming increasingly im­­ portant and may affect the type of construction and layer structure. Drafting accompanying environmental performance assessments at an early stage can help planners make the right choices.

Environmental factors

The more timber is used in a building, the more carbon it binds in the long term. The resulting CO2 sink has a positive effect on

Further criteria in positioning layers in horizontal and sloping structural components in building envelopes Even when the functional layers described above are incorporated into vertical, horizontal and sloping structural components in building envelopes, there are other aspects of the arrangement of layers that must be taken into account, depending on their position.

c

C 3.17

C 3.16 Typical facade structures of multi-storey timber buildings with insulation on the outside, including fire prevention cladding (structure of a and b as for [11])

a Solid timber structure with composite thermal insulation system

b Solid timber structure, rear-ventilated

c Solid timber structure (with exposed timber i­nterior) rear-ventilated, minimal use of foil C 3.17 Typical facades multi-storey timber buildings with insulation in interstices, including fire ­prevention cladding (structure of a and b as for [12])

a Timber panel structure with composite thermal insulation system

b Timber panel structure, rear-ventilated

c Timber panel structure, rear-ventilated, ­minimal use of foil

103

Part D Process

1 Planning Features of planning a timber building The planning process The digital process chain in timber construction

130 130 130

2 Timber production The raw material industry Industrial panel prefabrication Subtractive manufacturing in timber construction companies Additive manufacturing in timber construction companies Prospects

138 138 139

3 Prefabrication Prefabrication and individuality From linear member to room module Prefabrication methods The influence of prefabrication on design and construction

142 142 144 147

135

140 140 141

148

4 Solutions for modernising buildings 150 Adding storeys 151 Facades 154

Fig. D Installation of a prefabricated facade element, student residence, Vancouver (CA) 2017, Acton Ostry Architects

129

Prefabrication Wolfgang Huß

D 3.1

Wood and wood-based composite materials are especially suitable for prefabricating large structural elements and components because of the ease with which they can be worked, the techniques used to join them, and the light weight of elements and room modules, which makes them easy to transport.

Prefabrication and individuality

D 3.1 Prefabrication of room modules, European School, Frankfurt am Main (DE) 2015, NKBAK D 3.2 Prefabrication of panel construction elements in an assembly hall D 3.3 Prefabrication of linear elements (linear members) a Schematic diagram b Office building in Augsburg (DE) 2015, lattkearchitekten D 3.4 Prefabrication of planar elements a Schematic diagram b LifeCycle Office Tower (LCT One), Dornbirn (AT) 2012, Architekten Hermann Kaufmann D 3.5 Prefabrication of modular room elements (room modules / modular construction) a Schematic diagram b Hotel extension, Bezau (AT) 1998, Kaufmann 96

142

The widespread image of prefabricated buildings is still largely shaped by the architecture of the 1960s and 1970s, which was characterised by the use of serial prefabricated steelreinforced concrete parts and can seem to embody unimaginative design, monotony, rigidity and a focus on joints. However, prefabricated high-rise buildings (Plattenbau), built on a large scale in Europe’s former socialist countries, were based on a technology completely contrary to the type of prefabrication used in timber construction. These high-rise buildings were efficient because they used many of the same structural components. The formwork for their prefabricated elements could be repeatedly reused and structural analyses, which are costly and complex to draw up, did not have to be modified.

Modern timber construction manufacturing does not rely on this type of rigid formula. Modern software can automatically generate frame data for even complex buildings (see “Planning”, p. 130ff. and “Timber production”, p. 138ff.).

Using CNC to plot a timber frame, the cost and effort involved in manufacture does not depend on different parts and it is only the cost and effort of planning and organisation that increases with the number of different types of elements. Automated manufacturing is also becoming more customised. In practice, this great freedom in construction is more problematic than any restrictions imposed by prefabrication. Large timber buildings now usually have a prototype character and their structures and joints are individually developed and optimised for each specific building. Developments in this area are producing innovations and high-quality detailed solutions, but they are generally only suitable for specific buildings.

More standardisation would greatly improve efficiency on several levels.

A comparison with conventional construction

Compared with industrial production, conventional construction does not seem entirely ­optimised. Its dependence on weather con­ ditions, the complex coordination of many ­separately commissioned tradespeople, and inherently unergonomic working conditions on the building site make processes inefficient.

Problems are often only identified and solved on the building site and late changes to plans often further delay progress. Work done by other trades sometimes damages work previously done by different groups. Schedules often cannot be met and additional costs only become clear during construction. The many work steps required on site and necessary drying times can greatly prolong construction periods and impact users and the neighbourhood equally, especially in urban settings. ­Prefabricated timber construction could be an effective alternative.

The tradition of prefabrication

Carpentry has always been closely connected with prefabrication. Historical log cabin structures and half-timbered buildings required at least the preparation of individual timbers in a workshop. Traditional carpenters’ joints are geometrically complex and demand a high degree of precision, which is much easier to achieve in workshop conditions protected from the weather. Here organisation can also be optimised and heavy tools are always on hand.

The production of a frame in a workshop, with the outlining of a structure on a scale of 1:1 and production, marking and the trial assembly of members, minimises the need for corrections on the building site. It is also easier to develop solutions for difficult points and to test the assembly of complex structures in advance in a workshop.

Some advantages in the construction process

Moving production into a workshop (Fig. D 3.2) makes assembly times on site shorter, which has two positive aspects for the construction of timber buildings. Firstly, the assembly phase

Prefabrication

D 3.2

through to completion of a sealed building envelope, which is critical for wood, a building material sensitive to moisture, can be extremely short, which minimises dependency on weather conditions. A sealed building envelope implies at least temporary sealing of roofs and exterior walls and installation of sealed facade elements. Prefabrication reduces both the risk of damage from moisture during the construction phase and the cost and effort involved in measures to protect structures from the weather.

The second aspect affects the overall construction period. The degree to which a building’s technology, interior fittings and building envelope are prefabricated is decisive in saving more time in the construction phase. Shorter

construction times have economic advantages that will have a varying impact for each project.

In the case of a new building built to replace an older one, expensive loss of use is reduced.

Prefabrication can also make it possible to work on existing buildings while they are in use, which would be impossible using conventional construction methods. For example, school buildings can be extended and renovated during holiday periods.

However, timber construction does not usually involve a shorter overall planning and implementation process, because the planning phase is more complex so it takes more time.

These types of projects stay “virtual” for a long time, so the investment costs of implementation must only be paid at a relatively

late stage and financing is only required for a shorter time.

A workshop’s protected conditions, which are ideal for manufacture, improve the quality of both implementation and process control. The ability to work independently of the weather, very short paths and the permanent availability of a complete assembly team, materials, and tools increase efficiency. An assembly bench is a much more ergonomic workplace than a scaffold. It is also easier to coordinate and control external tradespersons in a workshop, and the risk of damage to already completed structures is much lower.

Prefabrication can also help to save materials: Elements are optimally cut to size in a process that is partly computer-controlled, and leftover

a

a

c

b

D 3.3

b

D 3.4

b

D 3.5

143

Solutions for modernising buildings

D 4.5 Load transfer

As well as meeting building regulations re­ quirements, the feasibility of adding one or more ­storeys is mainly a question of the ­existing building’s load-bearing capacity. ­Adding one or more storeys will depend on the structural load reserves of existing ­foundations, columns, walls and ceilings. The low weight of timber structures compared with masonry or concrete means that they ­impose lighter loads on an existing building’s structure. This means that the horizontal inertia forces resulting from the new structures in the event of an earthquake will be relatively minor.

If the existing structure no longer meets the more stringent structural stability requirements for the event of an earthquake, it must be re­ inforced by additional longitudinal and trans­ verse bracing.

Loads from added storeys are transferred either directly into existing structural compo­

nents or into additional walls or columns, which can also be integrated into the plane of a new added facade. A timber structure’s lower weight means that it is sometimes possible to concentrate load bearing at points in the existing building and position load-bearing structural components in the building’s interior, keeping the facade largely free of load-bearing elements, and thereby giving planners more freedom to design openings. The four storeys added to a residential and commercial building in Zurich (see p. 198ff.), which were built with­ out additional reinforcement [2], are an example of this approach. Its timber frame walls and ­hollow box slabs reduce the structure’s dead weight by more than 50 % compared with solid structures built with mineral materials.

It may be necessary to upgrade existing struc­ tural components as part of the modernisation.

Top-storey slabs, especially in buildings built in the 1950s and 1960s, are often thin and have

D 4.6

152

Solutions for modernising buildings

Composite wood panel screwed on

Composite timber-concrete slab

a Reinforcement

Addition of a cross laminated timber panel

Addition of a beamed section

b Retrofitting

no additional load reserves [3]. Here reinforce­ ment will be necessary if the existing struc­ ture’s load-bearing capacity, soundproofing or bracing has to be upgraded. The following structural options can be effective in this con­ text (Fig. D 4.7): • Reinforcing the original slab’s shear strength (e.g. by screwing a composite wood panel to it or installing a composite timber-concrete slab) • Upgrading the load-bearing section (e.g. by fitting a layer of joists or cross laminated timber panel) • Replacing the existing structure with a new timber slab.

New beamed section

New cross laminated timber panel

c Replacement D 4.7

Reaction to existing building

The simplest form of extension is the renovation, upgrading or replacement of the whole roof truss. If one or more storeys are added, the new room structure will be determined by the existing access, the arrangement of loadbearing walls and columns to form spaces, and the supply and service shafts for technical building equipment. Integration of these struc­ tural elements often conflicts with the need for different rooms due to new usage or a desire for greater design freedom. Light, large-format timber panel wall elements and ceiling and roof structures with long spans such as beam, dowel laminated timber, cross laminated timber or hollow box ceilings can be used to follow the arrangement of existing walls or columns (Fig. D 4.8), or the new support structure can be positioned transverse to the main direction of D 4.5 Construction under a temporary roof, Treehouse Bebelallee, Hamburg (DE) 2010, blauraum A ­ rchitekten D 4.6 Treehouse Bebelallee, Hamburg (DE) 2010, blauraum Architekten D 4.7 Various ways to strengthen slab structures: a Reinforcing the shear stiffness of the origi­ nal slab b Reinforcing a load-bearing section c Replacing an existing structure with a new ­timber slab D 4.8 Timber structural elements follow an existing load-bearing structure of walls and slabs D 4.9 Timber structural elements positioned obliquely on an existing load-bearing structure D 4.10 Geometries of added storeys

D 4.8

D 4.9

D 4.10

153

Part E Examples of buildings in detail

E 1 Joints in detail

160

01 Acton Ostry Architects, Student residence in Vancouver

166

02 Kaden Klingbeil Architekten, c13 residential and office building in Berlin

170

03 Rossiprodi Associati, Via Cenni residential complex in Milan

174

04 pool Architekten, Residential and commercial building in Zurich

178

05 OOPEAA, Residential complex in Jyväskylä

182

06 Deppisch Architekten, Residential complex in Ansbach

186

07 Bucher-Beholz Architekten, Terraced houses in Munich

190

08 Florian Nagler Architekten, Residential development above car park in Munich

194

09 burkhalter sumi architekten, Addition of further storeys and conversion to a residential and commercial building in Zurich

198

10 lattkearchitekten, Renovation of a residential building in Augsburg

202

11 Rolf Mühlethaler, Zollfreilager housing complex in Zurich

206

12 Florian Nagler Architekten (system development and design), Kampa GmbH (construction), 211 Kampa administration building in Aalen 13 Architekten Hermann Kaufmann, Illwerke Zentrum Montafon in Vandans

214

14 architekturWERKSTATT, Office building in St. Johann in Tirol

220

15 Michael Green Architecture, Wood Innovation and Design Centre in Prince George

224

16 Bruno Mader, Office building in Clermont-Ferrand

228

17 Cukrowicz Nachbaur Architekten, Community centre in St. Gerold

232

18 Architekten Hermann Kaufmann and Florian Nagler Architekten, Secondary school in Diedorf

236

19 NKBAK, European School in Frankfurt am Main

242

20 Agence R2K, School complex in Limeil-Brévannes

246

21 Fink Thurnher, Renovation and new addition to a boarding school in Altmünster

250

22 Oskar Leo Kaufmann and Albert Rüf, Hotel Ammerwald near Reutte in Tirol

254

Fig. E Residential complex in Jyväskylä (FI) 2015, OOPEAA

159

Example 11

Zollfreilager housing complex Zurich, CH 2016 Architect: Rolf Mühlethaler Team members: Thomas Moser (project leader), Chantal Amberg, Julia Grommas, Marion Heinzmann, Sandra Stein, Jonas von Wartburg, Simon Wiederkehr Structural engineers (solid construction): Ingenta Ingenieure + Planer, Berne Structural engineers (timber): Indermühle Bauingenieure, Thun Concept On the site of the former customs warehouse in Albisrieden in Zurich, a new residential district comprising around 190 apartments has been built. The units are divided between three solid multi-storeys made of reinforced concrete and three rows of timber buildings each of six storeys. Continuous balconies give the timber buildings a strong horizontal structure that mediates between the large scale of the buildings themselves and the small scale of the apartment facades. Window widths and the depths of balcony zones vary depending on their geographic direction and are designed in accordance with an ambitious energy concept

206

A B C

(Minergie-P-eco). The deep balconies offer weather protection for the wood facade made of pressure-treated spruce and create differentiated outdoor areas.

Staircase cores from front to back made of reinforced concrete provide access to two apartments on each level – a principle that repeats itself on every storey.

The apartments in the two northern building rows (A and B) consist of a series of neutraluse rooms that are accessed via a large ­interior room. They have no hallways. Apartments in the southern building row (building C) are centred around an open cooking /dining / living area.

Support structure The clarity and consistency of each layout is reflective of the different support structures.

The ceilings of buildings A and B rest on the longitudinal facades and on two middle walls that run parallel to those facades. The ceilings of building C span the longitudinal facades and rest on interior walls that form a regular crosswall structure. In both cases, the ceilings are made of dowel laminated timber elements and OSB panels provide reinforcement. Although the buildings have six storeys, vertical loads are successfully transferred via interior and exterior walls made of prefabricated timber panel elements.

Zollfreilager housing complex in Zurich

Plan Scale 1:5,000 Axonometries, load distribution compared Sectional view • Floor plans Scale 1:500

Buildings A and B

1 Living / dining / kitchen 2 Bedroom 3 Apartment foyer 4 Bathroom 5 Plant room 6 Access 7 Vestibule 8 Underground garage entrance 9 Bicycle room

Building C

aa

b

4 2 3

2

a

22

a 2

5

1

1

5 2

2

4 3 6

1

1 4

43

2

2 3

3 6 7

7 9

2

99

b

9

7

3

7 a

b

a

b

Ground floor, building A

8

8

5 3

1

14 2

5

2

2

12

2

3 4 6 2

6 7

79

99

97

7

1

Ground floor, building C

207

Example 13

A

B

sections measuring 2≈ 24 ≈ 24 cm. By using a reinforced concrete edge beam integrated in the ceiling element, the load can be transferred from the end-grain wood of the upper stanchion directly to the end-grain wood of the lower stanchion without the use of costly fasteners.

Assembly The entire timber structure, including the ­prefabricated facades with untreated oak exterior cladding and the roof elements, was assembled in just six weeks. Even the prefabricated oak windows were installed at the same time that the timber structure was being assembled. This minimised the risk that the 216

C

structure would be soaked during assembly and, in turn, the steps needed to protect the structure from weather.

Fire safety The entire structure has been left visible and was built to fire classification REI 90. A sprink­ ler system was installed as a compensatory measure. This enabled all of the aboveground storeys to form a single fire compartment, which was divided into several smoke compartments.

Energy The building’s primary energy consumption is less than 30 kWh/m2a, and its heating

needs are 14 kWh/m2a (passive house standard). This is supplied entirely by the power plant’s waste-heat system, while cooling energy is supplied using cold water from the surrounding reservoirs.

Building characteristics Number of storeys Gross floor area Construction costs Construction time (timber) Total construction time

5 11,497 m2 EUR 26 million net 6 weeks 17 months

Illwerke Zentrum Montafon in Vandans

A Building assembly sequence B LCT system (LifeCycle Tower One, Dornbirn, ­predecessor building and first eight-storey timber building in Austria) C IZM system D Assembly sequence in detail E Isometry of the support system F Timber-concrete-composite ribbed ceiling, vertical section Span 8.50 m, element width 2.70 – 3.00 m

1 Wall element consisting of three pairs of upright supports with parapet 2 Timber-concrete-composite ribbed ceiling 3 Window module 4 Canopy 5 Supports made of glued laminated timber 2≈ 240 ≈ 240 mm 6 Reinforced concrete C30/37 d = 80 mm with polypropylene fibres 7 Timber ribs e = 860 mm

2

3 5

1 4

E

6

D

7

F

217

Example 18

Vertical section Middle axis and facade Scale 1:20 1 Roof structure: Greening, extensive substrate 40 mm Drainage filled with substrate 40 mm Non-woven storage layer Waterproofing, EPDM root-proof 10 mm Thermal insulation, mineral wool 20 mm Timber battens, between them thermal insulation, mineral wool, pressure-resistant 60 mm Thermal insulation, mineral wool, pressure-resistant 160 mm Timber battens 100/160 mm, between them thermal insulation, mineral wool, pressure-resistant 160 mm Prefabricated roof element: Waterproofing Bitumen membrane Lightweight wood-wool panels in edge area and ­support area 50 mm (otherwise three-layer panel, spruce) Rafters, glued laminated timber, spruce, glazed white 100/360 mm 2 Gutter, inside 3 Sun protection Flat slats, aluminum, white 4 Timber window, spruce, glazed white with insulated triple glazing 4 mm float + 18 mm internal gap + 4 mm float + 18 mm internal gap + 4 mm tempered safety

240

glass /heat-soak-tested 5 Window sill, outside, aluminum 6 Facade element hung on exterior wall: Cladding, spruce, vertical, unplanned positioning, with different board widths 30 mm Substructure, timber battens, 40 ≈ 40 mm Exterior wall element: Timber battens, horizontal 40 mm Timber battens, vertical 110 mm Wind paper Wood fibreboard, permeable, waterproof 16 mm Supporting structure, spruce, filled with thermal insulation, mineral wool 140 mm Supporting structure, spruce, filled with thermal insulation, mineral wool 220 mm OSB panel (vapour retarder), glued joinings 18 mm 7 Window sill, inside, three-layer panel, glazed white 8 Room ventilation, displacement diffuser 9 Built-in shelving, three-layer panel, spruce, glazed white 42 mm 10 Interior wall structure: Gypsum fibreboard 12.5 mm OSB panel 18 mm Supporting structure, spruce 80/60 mm, filled with thermal insulation, mineral wool 80 mm

OSB panel 18 mm Gypsum fibreboard 12.5 mm 11 Ceiling slab: Mineral coating 5 mm Heating screed, perforated plate 85 mm Separation layer, PE foil Impact sound insulation 30 mm Levelling insulation 50 mm Separation layer PE foil, two-ply Reinforced concrete 98 –120 mm Ceiling element battens OSB panel 22 mm Frame of joists 2≈ 180/320 mm Filled with acoustic element: Thermal insulation, mineral wool 40 mm wood-wool acoustic panel, magnesite-bonded 12 Fixed glazing, laminated glass made of 2≈ 12 mm float glass 13 Edge beams, glued laminated timber 100/740 mm 14 Foundation structure: Mineral coating 5 mm Heating screed, perforated plate 85 mm Separation layer, PE foil Impact sound insulation 30 mm Levelling insulation 50 mm Separation layer PE foil, two-ply Reinforced concrete 250 mm Thermal insulation 80 mm 15 Ventilation channel

Secondary school in Diedorf

1

2

3 4 7

5

10 10 12 9 9 8

8 8

6

11

3 13 4

8

14 14

15 15

241

Authors Hermann Kaufmann born 1955 Univ.-Prof. Dipl.-Ing. certified architect Studied architecture at the Technical University of ­Innsbruck and the Technical University of Vienna 1981 –1983 Employed at office Hiesmayr in Vienna Founded own architectural firm in Schwarzach, Vor­ arlberg in an office shared with Christian Lenz, with a focus on sustainable building and the possibilities of modern (multi-storey) timber construction 1995 –1996 Guest lecturer for Timber Construction at the Liechtenstein Engineering School (LIS) 1998 Visiting professor at Graz University of Technology 2000 Visiting professor at the University of Ljubljana since 2002 Professorship of Architectural Design and Timber Construction at the Technical University of Munich (TUM) Stefan Krötsch born 1973 Junior Prof. Dipl.-Ing. certified architect 1994–2001 Studied architecture at the Technical ­University of Munich and the Wrocław University of Science and Technology in Wrocław, Poland 2001– 2003 Employed at bogevischs buero, Munich 2003 – 2005 Project manager at Söldner und Stender Architekten, Munich 2005 – 2013 Architekturbüro Stefan Krötsch in Munich 2008 – 2014 Academic Council at the Professorship of Architectural Design and Timber Construction, Prof. Hermann Kaufmann, Technical University of Munich since 2009 Braun Krötsch Architekten in partnership with Florian Braun since 2015 Junior professor, head of the newly founded Department of Tectonics in Timber Construction, ­Faculty of Architecture at the Technical University of Kaiserslautern (TUK) Stefan Winter born 1959 Univ.-Prof. Dr.-Ing. 1980 –1982 Carpenter training 1982 –1987 Studies of Civil Engineering at the Technical University of Munich and the Technical University of Darmstadt 1987–1990 Research assistant at the Institute of Steel Construction and Materials Mechanics and at the Institute of Concrete Construction at the Technical University of Darmstadt 1990 –1993 Director at the Institute of Carpenters, Darmstadt 1993 Founded engineering company bauart Kon­ struktions GmbH & Co. KG, with headquarters in ­Lauterbach and branches in Munich, Darmstadt and Berlin 1993 – 2003 Specialist consultant for the information service Informationsdienst Holz in Hesse 1998 doctorate at the Technical University of Darmstadt, dissertation topic “Structural behaviour of steel-­ concrete composite columns out of high tensile steel StE 460 under normal temperature and fire ­conditions” since 2000 publicly appointed and sworn expert for timber construction at the Gießen-Friedberg Chamber of Industry and Commerce (IHK) 2000 – 2003 Chair of Steel and Timber Construction, University of Leipzig 2001– 2010 Shareholder at MFPA Leipzig GmbH since 2003 Full professor of Timber Structures and Building Construction at the Technical University of Munich since 2006 check engineer for structural analyses in the timber construction field, Bavaria 2009 – 2012 Finland Distinguished Professor (FiDiPro) at Aalto University, Helsinki

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since 2012 Chairman of the construction standards committee Department 04 “Timber Construction”, ­member of the DIN Standards Committee Building since 2014 Chairman of the European standards com­ mittee CEN TC 250 / SC 5 Eurocode 5 – Timber construction – Design and Execution Heinz Ferk born 1961 Dipl.-Ing. 1990 Degree in civil engineering with honours, Graz ­University of Technology 1991–1996 University assistant at the Institute for Structural Engineering, Graz University of Technology 1996 Founded engineering office for building physics since 1998 Lecturer at the Graz University of Tech-­ nology since 2000 Head of the Laboratory for Building Physics at the Graz University of Technology since 2004 Head of European notified accredited testing laboratory 2006 – 2014 Deputy director of the Institute for Structural Engineering, Graz University of Technology since 2014 Deputy director of the Laboratory for Structural Engineering (LKI) Sonja Geier born 1973 Dipl.-Ing. 1991– 2000 Studied architecture at the Graz University of Technology 2006 Course in International Project Management at the Vienna University of Economics and Business 1992 – 2008 Work and project management at various architectural and civil engineering firms 2008 – 2012 International and national research projects at AEE INTEC in the area of sustainable buildings and timber construction since 2012 International and national research projects at the Lucerne University of Applied Sciences and Arts – Engineering and Architecture in the area of timber construction and planning processes Annette Hafner born 1971 Prof. Dr.-Ing. certified architect 1990 –1997 Studied architecture at the Technical University of Munich and ETSAB Barcelona 1998 – 2004 Architect in London and Munich 2004 – 2014 Research assistant at the Chair of Timber Structures and Building Construction, Prof. Winter and head of Certification Body ZQ MPA BAU, Technical ­University of Munich 2012 Doctorate at the Department of Civil Engineering and Surveying, Technical University of Munich since 2014 Junior professor at the Chair of Resource ­Efficient Building at the Ruhr-University Bochum, Department of Civil and Environmental Engineering Wolfgang Huß born 1973 Prof. Dipl.-Ing. Architect 1994 – 2000 Studied architecture at the Technical University of Munich and ETSA Madrid, graduated 2000 2000 – 2007 Employed architect at SPP Munich 2007 – 2016 Teaching and research assistant at the ­Professorship of Architectural Design and Timber ­Construction, Prof. Hermann Kaufmann, Technical ­University of Munich since 2013 firm hks � architekten (Huß Kühfuss Schühle) since 2016 Professor of Industrialised Construction and Production Technology, Faculty of Architecture and Civil Engineering, Augsburg University of Applied Sciences

Holger König born 1951 Dipl.-Ing. certified architect, book author 1971–1977 Studied architecture at the Technical University of Munich Working for environment and health in the building sector for over 30 years Maren Kohaus born 1975 Dipl.-Ing. certified architect Studied architecture at the Technical University of ­Dortmund, Technical University of Munich, ETSA Madrid 2001– 2008 Employed at Allmann Sattler Wappner Architekten, Munich 2008 – 2012 Member of the Executive Board at Allmann Sattler Wappner Architekten, Munich since 2012 Research assistant /Academic Council at the Professorship of Architectural Design and Timber Construction, Prof. H ­ ermann Kaufmann, Technical ­University of Munich since 2012 work as a freelance architect 2015 – 2016 Lecturer at the Technical University of Munich Frank Lattke born 1968 Dipl.-Ing. certified architect, Association of German ­Architects (BDA) Carpentry training, studied architecture at the Technical University of Munich and ETSA Madrid since 2003 own firm in Augsburg 2002 – 2014 Research assistant at the Professorship of Architectural Design and Timber Construction, Prof. Hermann Kaufmann, Technical University of Munich Teaching and research activity: TES EnergyFacade (WoodWisdom ERA Net) smartTES (WoodWisdom ERA Net) 2014 – 2017 Project partner in the leanWOOD research project Lutz Müller born 1969 1989 –1992 Carpentry apprenticeship in Munich 1995 –1999 Studied architecture at the Konstanz University of Applied Sciences 1999 – 2001 Employed at Prof. Wolfgang Lauber und Prof. Steidle + Partner, Munich 2001– 2005 Employed at RRP Architekten, Munich 2005 – 2014 Project manager at agmm Architekten, Munich 2007 Research assistant at the Professorship of Building in the Tropics, Prof. Dr. Wolfgang Lauber, Konstanz ­University of Applied Sciences 2007– 2009 Graduate studies under Prof. Hans Kollhoff at the ETH Zurich 2011– 2014 Studied art history at the Ludwig Maximilian University of Munich 2015 Employed at Henn Architekten, Munich since 2015 Assistant at the Professorship of Architectural Design and Timber Construction, Prof. Hermann Kaufmann, Technical University of Munich since 2016 Employed at Gassmann Architekten, Munich Anne Niemann born 1976 Dipl.-Ing. certified architect 1996 – 2002 Studied architecture at the Technical University of Munich, ETSA Madrid and Ben-Gurion University of the Negev 2003 – 2009 Partner at Niemann Ingrisch Architekten, Munich

2006 German Academy Rome Villa Massimo: fellowship at Casa Baldi, Olevano Romano, Italy 2008 – 2014 Assistant at the Professorship of Architectural Design and Timber Construction, Prof. Hermann Kaufmann, Technical University of Munich 2009 – 2013 Partner at m8architekten, Munich since 2014 Research assistant at the Professorship of Architectural Design and Timber Construction, Prof. Hermann Kaufmann, Technical University of Munich since 2017 Research assistant at the Chair of Architectural Design and Construction, Prof. Florian Nagler, Technical University of Munich

Gerd Wegener born 1945 Univ.-Prof. Dr. Dr. habil. Drs. h.c. TUM Emeritus of ­Excellence 1993 – 2010 Full professor of Wood Science and Wood Technology and Head of Holzforschung München (HFM) at the Technical University of Munich over 400 wide-ranging publications on forestry and wood science visiting professorships and expert reviewer around the world numerous awards and distinctions

Daniel Rüdisser born 1974 Dipl.-Ing. certified technical physicist and building p ­ hysicist Work on research projects on the topic of heat, humidity and climate at the Laboratory for Building Physics, Graz University of Technology. Owner of the engineering office HTflux, which focuses primarily on developing building physics software Christian Schühle born 1971 Dipl.-Ing. certified architect 1995 – 2002 Studied architecture at the Technical ­University of Munich 2000 – 2005 Employed at Herzog & de Meuron in Munich and Basel since 2007 own architecture firm, since 2013 hks � architekten (Huß Kuehfuss Schühle) since 2010 Research assistant at the Professorship of Architectural Design and Timber Construction, Prof. Hermann Kaufmann, Technical University of Munich Manfred Stieglmeier born 1962 M Eng architect 1982 –1991 Studied architecture at the Academy of Fine Arts Munich, University of Applied Sciences Munich 1987–1998 Employed at various Munich architecture firms, including Auer + Weber among others 1999 – 2000 Partner at Schmidhuber + Partner 2007– 2009 Graduate studies in timber construction for architects at the Rosenheim University of Applied Sciences since 2000 own firm in Munich with focus on timber ­construction since 2009 Research assistant at the Professorship of Architectural Design and Timber Construction, Prof. Hermann Kaufmann, Technical University of Munich Martin Teibinger born 1972 Dipl.-Ing. Dr. techn Combination studies in the timber industry at the University for Soil Culture and Structural Engineering at the Technical University Vienna Doctorate at the Technical University Vienna For over 20 years, active in the Construction Technology Department at Holzforschung Austria since 2006 Head of the Department of Building Physics Research, appraisal and publication activities in the fields of building physics, fire protection and multi-­ storey timber construction since 2016 Sworn and court-certified expert Lecturer and teacher in the fields of building physics, ­timber construction and fire protection as ­university lecturer, university of applies sciences ­lecturer and technical college teacher

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Glossary Acetylation Chemical modification of wood using acetic anhydride to prevent infestation by wood-destroying fungi or insects, reduce the timber’s moisture absorption and minimise swelling and shrinking. It makes sections of timber ­exposed to weather and moisture much more durable.

Airborne sound Sound transmitted by air.

Airtight layer Airtight layer in a structural component (usually the ­building envelope) between different temperature levels to prevent air convection through and in the structural component. Prevents energy losses caused by warm ­interior air escaping out of the component and damage to the structural component from moisture due to the permeation of warm, moist interior air and condensation of moisture on cold surfaces. Airtight layers in interior structural components primarily have the function of preventing the transmission of airborne noise and obstructing smoke and fire. They are usually identical with the vapour seal / vapour barrier. Often made of airtight, composite wood-based boards that inhibit diffusion (OSB, 3-ply or parallel strand lumber) with joints between boards glued to make an airtight surface.

Airtightness Buildings now have to be very airtight to prevent heat losses, damage due to moisture and sound transmission.

A building’s airtightness should be tested during construction and /or renovation (with a blower door test and measures to locate leaks). A continuous airtight layer in the building envelope or between building sections will ensure airtightness.

Anisotropy Directional dependency of certain physical properties.

In timber construction, this usually refers to wood’s varying properties in parallel with its fibres and perpendicular to them.

Annual heating requirement A measurement of the amount of heat in kilowatt-hours per square metre per year (kWh/m2a) required to maintain a pleasant interior temperature. It is based on a balance of the heat gains and losses occurring in a building.

Battens Defined in DIN 4074-1 as sawn timber up to 40 mm thick and up to 80 mm wide; roof battens: 24/48, 30/50, 40/60 mm.

Beam Horizontal linear element in a slab structure, usually in a layer of frame of beams or joists. Individual beams or joists or primary parts of a frame structure are referred to as beams.

Block or log-cabin construction Wall structure made of horizontally layered, linear cross sections (often solid timber or squared timber, historically also logs) braced by corner joints.

Blower door test Test that measures the airtightness of building envelopes and identifies leaks by creating positive and negative pressure in the building. An important tool in determining a building’s quality.

Board Sawn lumber up to 40 mm thick and over 79 mm wide (DIN 4074-1). DIN 4070-1 specifies rough-sawn board thicknesses as 16, 18, 22, 24, 28 and 38 mm.

Bottom diagonal brace Angled joining member installed by a carpenter between a bottom plate and a stud (see top diagonal brace) to stabilise a frame. A top diagonal brace sits up under a

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roof beam, while a bottom diagonal brace sits below on a bottom plate. The installation of top diagonal braces is more common than bottom diagonal braces.

Bottom plate Horizontal member at the bottom of the framework of a timber frame, stud frame, framing or panel construction wall or a horizontally laid bottom support beam in a timber structure. Usually squared solid wood or glulam, sometimes also hardwood or parallel strand lumber for absorbing higher compressive loads (see also crosspiece, crosspiece compression).

Composite structure Structural component or structural element whose loadbearing capacity is based on the intrinsic interaction of various individual parts, e.g. a wooden slab structure with a top layer of concrete as the tensile and compressive zone of a composite timber-concrete slab or the ribs and planking of a box slab element.

Box beam Beam or girder with a square, hollow cross section consisting of a top flange, a bottom flange and two webs.

They can be made of boards, panel materials or glulam.

Condensation Transition of material from a gaseous to a liquid state.

In construction, condensation formation usually refers to a cooling of interior air in a structural component or on cool surfaces. Condensation forms when the temperature falls below the dew point, and it can cause damage to a structural component and hygiene problems (mould).

Condensation usually results from leaks in the building envelope’s airtight layer or in and around thermal bridges.

Box slab / Box slab element Slab structures consisting of box slab elements. The elem­ ents are made of slender ribs that follow the slab’s main span direction. Combined with the edge beams to form a frame, they are joined to the planking, making them structurally effective. From a structural perspective, the individual components make up a composite element, a box.

Construction method / technique Generalisable construction principle for a building’s ­support structure (e.g. frame or crosswall construction), materials (e.g. timber or hybrid construction), degree of prefabrication and assembly (e.g. panel or module construction) or structural use of materials (e.g. lightweight or solid construction).

Building Information Modelling (BIM) Method of optimising construction work processes using a digital three-dimensional model of the building over its entire life cycle, from planning through to dismantling.

Convection The word “convection” generally refers to transport in a flow, in construction usually to the transport of heat and / or water vapour. Convection of interior air through a building envelope can result in considerable energy loss and produce large quantities of condensation in structural components. Water vapour convection can result in much larger amounts of condensation than water vapour diffusion causes.

CAD (Computer Aided Design) Computer-aided design and planning.

CAM (Computer Aided Manufacturing) Computer-aided manufacturing.

Carbon store Storage of carbon as a material. Timber products store carbon temporarily because a tree absorbs carbon ­dioxide (CO2) from the atmosphere as it grows and stores it as carbon (C) until the wood is burnt, when the carbon is released as CO2.

Cellulose Cellulose is the main constituent of wood and, together with lignin and hemicellulose, forms the structural substance of cell walls and the raw material used for making paper. One frequent application for cellulose in timber construction is in cellulose insulation, which can be installed as blown-in insulation in the cavities of panel construction elements. It is an inexpensive and high quality ecological material.

Chipboard / Particle board Board made of bonded wooden chips or particles. Bonding agents used include glue, synthetic resin or cement.

Climate neutrality / Climate neutral Processes are described as “climate neutral” when no gases that impact the climate are released or the amount of gas emitted is conserved elsewhere in the process, i.e. emissions do not change the atmospheric balance of gases. This evaluation is based on emissions of climaterelevant gases, especially CO2 (measured in GWP 100).

CNC (Computerised Numerical Control) Electronic process used to control tooling machines, which are able to automatically process complex parts with high precision. Industrial looms were the precursors of today’s CNC machines.

CNC milling machines Tooling machines that use modern control technologies to automatically make parts, including complex forms, with great precision. Most milling machines can be fitted by means of tool changers with various milling machine tools, saw blades, drills and other special tools.

Column In timber construction, often used as a synonym for a ­pillar or post.

Counter battens Battens installed perpendicular to the main support ­battens, making it possible to use horizontal battens to construct a continuous rear ventilation cavity.

Cross laminated timber – CLT Planar structural elements made of an odd number of ­layers of boards up to 40 cm thick that are laid crosswise and glued together. Various manufacturers supply different formats.

Crosspiece / Crosspiece compression Structural components exposed to loading perpendicular to the direction of their fibres. Wood’s load-bearing ­capacity is more than three times as strong in the ­direction of its fibres than perpendicular to its fibres. A crosspiece is unfavourable from a static and structural point of view in load-bearing structural components in taller buildings (three floors and higher) and should not be used, because subjecting wood to compressive forces perpendicular to its fibres causes it to subside, which can lead to problems with rigid structural components and sections (e.g. reinforced concrete staircases).

Density Wood’s proportion of mass to volume (g/cm3 or kg/m3) at a specific temperature and humidity. Its density varies depending on the wood’s moisture content. Normal ­density is determined at 20 °C and 65 % humidity after storage, while “oven-dry” wood is absolutely dry (0 % wood moisture content).

Dew point Short for “dew point temperature”. Condensation can form in structural components when the temperature falls below this point. The dew point temperature depends on the ambient air temperature and humidity.

Diffusion Physical process of complete mixing of various sub­ stances until their particles are evenly distributed. In construction, diffusion usually refers to the material transport of water vapour through an exterior structural component when interior air is moist and outside air is dry in winter.

Condensation can form in structural components that are not properly built, so the diffusion resistance of layers

of exterior structural components should decrease from the inside towards the exterior.

Dowel laminated timber Material used to make structural components consisting of boards or beams (squared timber) that are stacked, nailed or doweled together (with hardwood dowels).

Slabs made of horizontal dowel laminated timber elem­ ents are called glued dowel laminated timber slabs.

Drying, artificial or technical Drying or curing in artificial climatic conditions, usually in a chamber kiln or flow channel. It can result in much lower final moisture levels and shorter drying times than natural or open-air drying.

Drying, natural or open-air Drying or curing of wood without using artificially produced thermal energy or dehumidification, a gentle ­drying method carried out mainly in well-ventilated rooms or outside, protected from the weather. Usually used for pre-drying. Depending on the degree of drying required, it can take 6 months to 2 years.

Elastic modulus (E modulus) The measure of a substance or object’s resistance to elastic deformation under mechanical stress or loading in its elastic deformation range.

Encapsulation Fire protection panelling with a protection period specified in minutes (capsule criterion, e.g. K2 30 or K2 60).

Encapsulation limits the temperature on the side not ­directly exposed to fire to T ≤ 300 °C for the period specified, thereby preventing wood from burning and adding to the fire load. Encapsulating panelling should also ­prevent fire from penetrating into structures made of panel construction elements with insulated or uninsulated cavities.

End grain wood Wood with a cut surface perpendicular to the direction of its fibres. End grain wood absorbs moisture very well through capillary action, so it requires particular protection in structural components exposed to weathering.

Compressive forces between structural components can be optimally transferred through joints in end grain wood surfaces without compression on crosspieces.

Energy source, fossil Energy sources containing carbon, such as oil or brown coal, which formed in the Earth’s geological past.

Energy source, renewable Renewable energy sources like wood are continuously ­renewed (e.g. from forestry) when the energy source is used sustainably, so they are permanently available.

Exposed surface quality Refers to a structural element’s suitability for use in its ­exposed form in the finished structure.

Facade, not rear-ventilated Exterior wall structure in which the facade surface is joined to the insulating layer with no gap, e.g. a com­ posite thermal insulation system or sandwich element (DIN 68 800-2).

the ­insulating layer and facade surface. Condensation can run off from the rear ventilation cavity and an exchange of air occur through an opening at the bottom end of it.

Finger joint Longitudinal joint between two solid wood or wood-based material structural components, a further development of the scarf joints used to join boards and beams since prehistoric times. A finger joint is usually also glued. Its tensile strength derives from the increased surface of the glued joint, which slopes slightly in the same direction as the wood’s fibres. Finger-jointed structural components have relatively high flexural or bending strength. When they are made in optimum production and quality assurance conditions, they can achieve almost the load-bearing capacity of structural components made of solid timber grown naturally in one piece.

Fire resistance Stipulated period during which a structural component so designated retains its load-bearing (R) and /or spaceenclosing (E) and/or insulating (I) functions in the event of fire.

Fire-resistant seal / Fire stop Prevents the uncontrolled spread of fire (e.g. in shafts, rear ventilation cavities).

Floor boards Boards at least 21 – 50 mm thick and relatively wide (from 80 mm). DIN EN 13 629 defines floor boards less than 40 mm thick as boards and thicker ones as planks.

Footfall or Impact sound Airborne sound caused by structure-borne impact sound in an adjoining space, e.g. when a slab vibrates because of someone walking or jumping on it.

Formaldehyde Formaldehyde (systematic chemical name: methanal) is a gaseous substance at room temperature. Its low ­boiling point (-19 °C) means that it belongs by definition not to the group of VOCs, but to the group of V VOCs (very volatile organic compounds, which vaporise at a boiling point < 0 to 50 … 100 °C). Formaldehyde has been used to make and process industrial products for almost 150 years. In 2016 the EU classified it as ­carcinogenic in animal experiments (1B).

Frame construction Construction method in which loads are supported by a load-bearing structure, a frame consisting of columns and beams. The building envelope and inner panelling is independent of the load-bearing structure. They can be either made on the building site or be prefabricated, nonload-bearing wall elements.

Framework Structure made of linear structural elements, e.g. stud walls, frame structure, spatial frameworks and panel construction wall structures made of linear members (studs, bottom plate, top plate), box slab or box slab elements.

Girder Linear, horizontal element laid on supports erected at ­various points that transfers vertical loads to columns or walls.

Heartwood The inner core of a tree trunk that is surrounded by ­concentric rings of sapwood, often distinguished by its darker colour. Unlike sapwood, it does not transport water or nutrients.

Hollow box Slab structure consisting of ribs and structurally effective planking (see box slab).

Hybrid building Structures made of different construction materials can be combined in a single building, such as a reinforced concrete access core (for emergency exits, building bra­ cing) integrated into a timber building or a timber element facade on a reinforced concrete frame structure.

Hybrid construction method / technique Hybrid structural components or elements made of ­different materials can be systematically used in a single structure, e.g. steel beams in cross laminated timber slab elements.

Hybrid structural component Various materials are combined to make some horizontal or vertical structural components. The best-known ex­ ample is the composite timber-concrete slab.

Indoor climate A term referring to all the conditions in a space that can impact the well-being and performance of its users. These conditions are influenced by air temperature, humidity and airspeeds, the content of contaminants in the air, the temperatures of the room’s surfaces and its lighting situation.

Inhomogeneity The inhomogeneity of wood refers to the irregularity of its mechanical, structural and physical properties due to factors such as knotholes, resin pockets, uneven fibre orientation and varying densities and strength. One of the goals in sorting solid wood and manufactured woodbased materials into types such as solid structural timber, dowel laminated timber elements, layered and veneered, fibre and chip and shaving materials is to ensure that the resulting timber product will be homogeneous.

Intumescent products Intumescent products foam up to close off any openings when they are subjected to heat loads, thereby preventing smoke and toxic gases (fire safety) from passing through them.

Laminated veneer lumber – LVL Wood-based material made of several compounded layers of veneers. The veneers are laid in layers with their fibres crossing at 90° angles and usually glued t­ogether with phenol-formaldehyde resin to form a water-resistant bond.

Leaks Airtight layers may leak (usually through joints between structural components or ducts and breaches made to ­install fittings etc.) despite having good measured airtightness values, resulting in damage to exterior structural components. A blower door test should always include measures to locate leaks. This test uses a positive and negative pressure differential in the building to enable builders to find and repair any leaks.

Facade, rear-ventilated Exterior wall structure in which there is an uninterrupted vertical rear ventilation cavity with an appropriate cross section (usually 2 cm; see DIN 68 800-2) between the ­insulating layer and facade surface, through which large amounts of air flow through openings with a suitable cross section (usually at least 50 % of the rear ventilation cavity) in the top and bottom ends due to the chimney effect.

Glued laminated timber / Glulam Linear cross sections made of glued boards (layers or ­veneers) laid in the same direction, normally 40 mm thick up to 30 cm wide, height of the cross section not glued is approx. 200 cm, and boards can be up to 65 metres long depending on the manufacturer. The maximum ­radius of curved glulam beams depends on the thickness of their layers.

Life-cycle assessment – LCA A life-cycle assessment is an established method for quantifying the environmental effects of a product or building. It makes it possible to compare the environmental effects of various products and environmental ­parameters of different types of buildings. The infor­ mation it yields is key in highlighting timber’s positive ­effects on the climate and it can be crucial to take it into account in making decisions.

Facade, ventilated Exterior wall structure in which there is an uninterrupted vertical rear ventilation cavity with an appropriate cross section (usually 2 cm; see DIN 68 800-2) between

Grey energy Energy used in the manufacture, storage, transport, ­installation and disposal of materials, structural components and buildings.

Lightweight construction Structures built using materials and components with a low volume or own weight or a widely spaced support structure (e.g. timber or steel frame).

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Image credits The authors and publisher would like to sincerely thank everyone who contributed to this book's production by providing images, granting permission to reproduce their work, and supplying other information. All the diagrams in this book were created especially for it. The authors and their staff created those graphics and tables for which no other source is credited. Photos for which no photog­ rapher is credited are architectural or work photos or come from the archive of DETAIL magazine.

Despite intensive efforts, we have been unable to identify the copyright holders of some images, but their entitlement to claim copyright remains unaffected. In these cases, we would ask you to contact us. Figures refer to ­illustration numbers.

Preface

Gataric Fotografie

Part A A

Christian Schittich

The development of multi-storey timber construction A 1.1 From: Weston, Richard: Utzon – Inspiration, Vision, Architektur. Kiel 2001, p. 48 A 1.2 HGPhotography A 1.3 mykyotomachia.com A 1.4 Sergio Somavilla A 1.5 Bernard Gagnon Neckar-Magazin, Esslingen / Neckar A 1.6 A 1.7 Peter Bonfig A 1.8 Bernd Borchardt A 1.9 Roland Pawlitschko A 1.10 TU Munich, Professor of Design and Timber Construction, Univ. Prof. DI Hermann K ­ aufmann A 1.11 Waugh-Thistleton Architects A 1.12 Artec Arkitekter A 1.13 RLP Rüdiger Lainer + Partner Wood as a resource A 2.1 Friedrich Böhringer A 2.2 Tourist Information Einbeck A 2.3 Munich Stadtmuseum, Graphics / Paintings collection A 2.4, 2.5 Gerd Wegener / Ralf Rosin, Holzforschung München A 2.6 TU Munich, Professor of Design and Timber Construction, Univ. Prof. DI Hermann Kaufmann A 2.7, 2.8 Ralf Rosin, Holzforschung Munich A 2.9 From: Kaufmann, Hermann; Nerdinger, ­Winfried (pub.): Bauen mit Holz – Wege in die Zukunft. Munich, London, New York 2012, p. 17 A 2.10 Michael Christian Peters / Pollmeier ­Massivholz Solid wood and wood-based products A 3.1a–d Heyer, Hans-Joachim, Werkstatt für Photo­ graphie, University of Stuttgart A 3.1e SWISS KRONO A 3.1f proHolz A 3.1g Holzabsatzfonds, Bonn A 3.1h Mathias Kestel A 3.1i – l Holzabsatzfonds, Bonn A 3.1m Mathias Kestel A 3.1n ARGE Holz, Düsseldorf A 3.1o – q Holzabsatzfonds, Bonn A 3.1r Mathias Kestel A 3.2 In: Rüter, Sebastian; Diederichs, Stefan: ­Ökobilanz-Basisdaten für Bauprodukte aus Holz. Arbeitsbericht aus dem Institut für ­Holztechnologie, No. 2012/1; published

by Johann Heinrich of the Thünen Institute.

Hamburg 2012

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Life-cycle assessment A 4.1 sps÷architekten, Thalgau A 4.2 From: Kaufmann, Hermann; Nerdinger, ­Winfried (pub.): Bauen mit Holz – Wege in die Zukunft. Munich, London, New York 2016, p. 52 A 4.3 Hafner, Annette, Schäfer, Sabrina: Metho­ denentwicklung zur Beschreibung von Ziel­ werten zum Primärenergieaufwand und ­CO2-Äquivalent von Baukonstruktionen zur Verknüpfung mit Grundstücksvergaben und Qualitätssiche­rung bis zur Entwurfsplanung.

Deutsche Bundesstiftung Umwelt, Aktenzeichen 31943/01 A 4.4 Annette Hafner A 4.5 From: Kaufmann, Hermann; Nerdinger, ­Winfried (pub.): Bauen mit Holz – Wege in die Zukunft. Munich, London, New York 2016, p. 47 A 4.6 Stefan Müller-Naumann Interior air quality – the influence of timber con­ struction A 5.1 Adolf Bereuter A 5.2 In: Leitwerte für TVOC in der Innenraumluft.

Compiled by the ad hoc working group under the auspices of the Federal Environmental Agency. Dessau 2007 A 5.3 In: Wikipedia A 5.4 From: Holzmann, Gerhard; Wangelin, Matthias; Bruns, Rainer: Natürliche und Pflanzliche Baustoffe. Wiesbaden 2012, p. 26 A 5.5 From: Bauen und Leben mit Holz. pub. by ­Informationsdienst Holz. March 2013, p. 23 A 5.6 From: Holzmann, Gerhard; Wangelin, Matthias; Bruns, Rainer: Natürliche und pflanzliche Baustoffe. Wiesbaden 2012, p. 33 A 5.7 TU Munich, Professor of Design and Timber Construction, Univ. Prof. DI Hermann Kaufmann A 5.8 In: Thünen Institute and Holzmann, Gerhard; Wangelin, Matthias; Bruns, Rainer: Natürliche und pflanzliche Baustoffe. Wiesbaden 2012, p. 32 A 5.9 TU Munich, Professor of Design and Timber Construction, Univ. Prof. DI Hermann Kaufmann A 5.10 TU Munich, Professor of Design and Timber Construction, Univ. Prof. DI Hermann Kaufmann A 5.11 In: Paulitsch, Michael; Barbu, Marius C.: ­Holzwerkstoffe der Moderne. Leinfelden-­ Echterdingen 2015, p. 418 A 5.12 Stefan Müller-Naumann A 5.13 From: König, Holger: Baustoffe – Lebens­ zyklusanalyse als Planungsinstrument. In: ­Djahanschah, Sabine; Kaufmann, Hermann; Nagler, Forian (pub.): Schmuttertal-Gymnasium. Architektur – Pädagogik – Ressourcen.

DBU Bauband 1. Munich 2016, p. 84 A 5.14 In: Raumluftqualität – Grundlagen und Massnahmen für gesundes Bauen. Published by Lignum. Zurich 2013, p. 27

Part B B

Eckhart Matthäus / lattkearchitekten

Structures and support structures B 1.1 Darko Todorovic B 1.7 a Architekten Hermann Kaufmann B 1.7 b, 1.10 Bernd Borchardt B 1.15 a proHolz Polaris B 1.15 b Bernd Borchardt B 1.15 c Architekten Hermann Kaufmann ETH Zurich B 1.17

B 1.18 TU Munich, Professor of Design and Timber Construction, Univ. Prof. DI Hermann Kaufmann B 1.20 a Margherita Spiluttini, © Architekturzentrum ­Vienna, Collection Structural components and elements B 2.1, 2.2 Matthias Kestel B 2.8 STEICO SE proHolz Polaris B 2.16 B 2.22 Finnforrest Bernd Borchardt B 2.27 B 2.31, 2.37 Mathias Kestel B 2.42 Ökoberatung G. Bertsch Binderholz GmbH B 2.49 B 2.53 Peter Cheret Architekten Hermann Kaufmann B 2.57

Part C C

ARTEC

Protective functions C 1.1 abcmedia – Fotolia C 1.2 In MBO (2012) C 1.3 In DIN 4102-2 and DIN EN 13 501-2 C 1.4 In Deutsches Institut für Bautechnik: Bauregelliste – Bauregelliste A, Bauregelliste B und Liste C. Issue 2015/2 C 1.5, 1.6 Technical University Munich C 1.7 In EN 1995-1-2 C 1.9 Stefan Winter C 1.10 Dianna Snape C 1.11 Emma Cross photographer C 1.16 a From: Zeumer, Martin; El Khouli, Sebastian; John, Viola: Nachhaltig konstruieren. Munich 2014 C 1.17 Huber & Sohn GmbH & Co. KG, Bachmehring C 1.18 Midroc, Photo: Martin Johansson C 1.19 a Photo: Bosch C 1.19 b Hilti, Kaufering C 1.20 David Borland C 1.21, 1.22 Stefan Winter C 1.23 Christian Schittich C 1.24 Stefan Winter C 1.25 Holzforschung Austria /Grüll C 1.26 Thomas Madlener C 1.27 Stein, René; Schneider, Patricia; Kleinhenz, Miriam et al.: Fassadenelemente für Hybridbauweisen – Vorgefertigte, integrale Fassaden­ elemente in Holzbauweise zur Anwendung im Neubau hybrider Stahlbetonhochbauwerke (unpublished). Chair of timber construction and structural design, Chair of energy-efficient and sustainable planning and construction and chair of massive construction. Technical University Munich 2016 Thermal insulation for summer C 2.1, 2.2 From: Ferk, Heinz; Rüdisser, Daniel et al., ­proholz Austria (pub.): Sommerlicher Wärmeschutz im Klimawandel – Einfluss der Bauweise und weitere Faktoren. In: att.zuschnitt.

Vienna 2016 C 2.3, 2.4 Daniel Rüdisser / Laboratory of construction physics at TU Graz C 2.5, 2.6 From: Ferk, Heinz; Rüdisser, Daniel et al., ­proholz Austria (pub.): Sommerlicher Wärmeschutz im Klimawandel – Einfluss der Bauweise und weitere Faktoren. In: att.zuschnitt.

Vienna 2016 The layer structure of building envelopes C 3.1 Bruno Klomfar C 3.2 In: Informationsdienst Holz und www.dataholz.com

C 3.4 Huber & Sohn GmbH & Co. KG, Bachmehring C 36 In: Winter, Stefan; Merk, Michael: Verbundforschungsprojekte Holzbau der Zukunft – Teilprojekt TP 02 – Brandsicherheit im mehrgeschossigen Holzbau. Technical University Munich, Chair of timber construction and structural design. Munich 2009 C 3.7 Adolf Bereuter Michael Meuter C 3.8 C 3.9 Bernd Borchardt C 3.16 a In accordance with DIN 68 800-2, A7; in: Merk, Michael et al.: Erarbeitung weiterfüh­ render Konstruktionsregeln /-details für mehrgeschossige Gebäude in Holzbauweise der Gebäudeklasse 4. Stuttgart 2014 C 3.16 b In accordance with DIN 68 800-2, A4; in: Merk, Michael et al.: Erarbeitung weiterfüh­ render Konstruktionsregeln /-details für mehr­ geschossige Gebäude in Holzbauweise der Gebäudeklasse 4. Stuttgart 2014 C 3.17 a In accordance with DIN 68 800-2, A5; in: Merk, Michael et al.: Erarbeitung weiterfüh­ render Konstruktionsregeln /-details für mehrgeschossige Gebäude in Holzbauweise der Gebäudeklasse 4. Stuttgart 2014 C 3.17 b In accordance with DIN 68 800-2, A2; in: Merk, Michael et al.: Erarbeitung weiterfüh­ render Konstruktionsregeln /-details für mehrgeschossige Gebäude in Holzbauweise der Gebäudeklasse 4. Stuttgart 2014 C 3.20 Bernd Borchardt C 3.22 In DIN 68 800 or www.dataholz.com C 3.28 RADON photography / Norman Radon The layer structure of interior structural components C 4.1 Ed White Photographics C 4.8 Köhnke, Ernst Ulrich: Schallschutztechnische Ausführungsfehler an Holzdecken, Beitrag zum 4 HolzBauSpezial: Akustik und Brand­ schutz im Holz- und Innenausbau (ISB 2013) Bad Wörishofen 2013 Building technology – some special features of timber construction C 5.1 Kiefer Holzbau GmbH & Co. KG, Stockach C 5.2 Informationsdienst Holz, Düsseldorf C 5.3 Manfred Mühe C 5.6 Informationsdenst Holz, Düsseldorf C 5.7 Eisedicht, Rinteln C 5.10 Kaiser GmbH & Co. KG, Schalksmühle C 5.11 Holzforschung Austria C 5.12 Informationsdienst Holz, Düsseldorf C 5.21, 5.22 Stefan Winter

Part D D Courtesy of the University of British Columbia Planning D 1.1 TU Munich, Professor of Design and Timber Construction, Univ. Prof. DI Hermann Kaufmann D 1.5 Gumpp & Maier, Binswangen D 1.9 a Merz Kley Partner D 1.9 b Achitekten Hermann Kaufmann D 1.9 c Kaufmann Bausysteme Timber production D 2.1 BDF / Vennenbernd, Bad Honnef D 2.2 Hajotthu, CC BY-SA 3.0 D 2.3 AxelHH, Wikipedia D 2.4, 2.5 Hans Hundegger AG D 2.7 Wenmann Holzbausystemtechnik GmbH D 2.8 a Renggli AG – Schötz, Switzerland D 2.8 b, c Weinmann Holzbausystemtechnik GmbH

Prefabrication D 3.1 RADON photography / Norman Radon D 3.2 Huber & Sohn GmbH & Co. KG lattkearchitekten D 3.3 b D 3.4 b Darko Todorovic / Cre D 3.5 b Ignacio Martinez RADON photography / Norman Radon D 3.7 D 3.11 thomasmayerarchive.de D 3.13 b Vielstädte Holzbau GmbH & Co. KG D 3.13 d Stefan Müller-Naumann D 3.13 f Architekten Hermann Kaufmann D 3.14 a Architekten Hermann Kaufmann D 3.15 Ignacio Martinez Solutions for modernising buildings D 4.1 lattkearchitekten Gumpp & Maier, Binswangen D 4.2 D 4.4 Bruno Klomfar D 4.5 Dominik Reipka Martin Lukas Kim D 4.6 D 4.11 Alexander Gempeler Eckhart Matthäus / lattkearchitekten D 4.20

Green Architecture, Vancouver) p. 226 bottom Courtesy of Forestry Innovation I­ nvestment p. 228, 230, 231 @ photo.Abbadie.Herve p. 232, 233, 234 bottom, 235 top Hanspeter Schiess p. 235 bottom Cukrowicz Nachbaur Architekten Carolin Hirschfeld p. 236, 239 –241 p. 237, 238 Stefan Müller-Naumann p. 242, 244 thomasmayerarchive.de p. 245 RADON photography / Norman Radon p. 246 –248 Lignotrend, Weilheim-Bannholz / Fotografie Uwe Röder, Bischweier p. 250, 251, 253 Walter Ebenhofer Fink Thurnher Architekten p. 252 p. 254, 255 left, 256 top, 257 Adolf Bereuter

Part E E

Mikko Auerniitty

Joints in detail p. 161 Gataric Fotografie p. 162 Hanspeter Schiess Pietro Savorelli p. 163 p. 164 Adolf Bereuter p. 165 RADON photography / Norman Radon Project examples KK Law; naturally:wood p. 166 p. 167 Courtesy of Seagate Structures.

Photographer: Pollux Chung p. 168 bottom Stefen Errico p. 169 top left Neil Taberner p. 169 top centre Neil Taberner p. 169 top right Stefen Errico p. 170 –173 Bernd Borchardt p. 174, 175, 177 Pietro Savorelli p. 176 proHolz Polaris p. 178 top Michael Meuter p. 178 bottom Jakob Schoof p. 179 Giuseppe Micciché p. 180, 181 top pool Architekten p. 181 bottom Giuseppe Micciché p. 182, 183, 185 Mikko Auerniitty p. 184 Juha Pakkala p. 186 –188 Sebastian Schels p. 189 Deppisch Architekten p. 190, 191, 193 Florian Holzherr p. 192 Bucher-Beholz Architekten p. 194 top Eva Schönbrunner p. 194 bottom, 195, 196 Stefan Müller-Naumann p. 198 left Sihltal Zürich Uetliberg Bahn SZU AG, www.szu.ch p. 198 right burkhalter sumi architekten p. 199 Unirenova (Stephanie Künzler) p. 200 top Pino Ala p. 200 bottom Heinz Unger p. 201 burkhalter sumi architekten p. 202 top, 203 lattkearchitekten p. 202 bottom Eckhart Matthäus p. 204 Guido Koeninger, Firma Keim­ farben p. 206 –210 Gataric Fotografie p. 211–213 KAMPA GmbH 214, 215, 218 Bruno Klomfar 217 left, centre Thomas Giradelli 217 right Darko Todorovic p. 220 –223 Christian Flatscher p. 224 –225, 227 Ed White Photographics ©2015 p. 226 top Photography by MAG (Michael

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The authors and the publisher would like to thank the following institutions for supporting the 1st German language edition:

www.stmelf.bayern.de

www.zimmerer-bayern.com

www. proholz.at