FHGraham | BA Hons. Architecture, Newcastle University

THE MATERIAL BOOKLET: GLUE-LAMINATED TIMBER

FLORENCE H GRAHAM 120270411

The Material Booklet: Glue-Laminated Timber As a structural material, what are the capabilities of glulam? How have engineered timber products replaced the traditional uses of timber? And are there changing views on the use of timber in modern construction? And how sustainable is it?

Newcastle University Architecture BA Honours Stage 3 Dissertation in Architectural Studies ARC3060 Florence H Graham 12027041

With dedication to my tutor, Steve Dudek, for all of his support.

"Each material has its specific characteristics which we must understand if we want to use it... This is no less true of steel and concrete [than of wood, brick, and stone]. We must remember that everything depends on how we use a material, not on the material itself... New Materials are not necessarily superior. Each material is only what we make of it... We must be as familiar with the functions of our buildings as with our materials. We must learn what a building can be, what it should be, and also what it must not be... And just as we acquaint ourselves with materials, just as we must understand functions, so we must become familiar with the psychological and spiritual factors of our day. No cultural activity is possible otherwise; for we are dependent on the spirit of our time."

Ludwig Mies van der Rohe From: his address at the Illinois Institute of Technology, 1938

ABSTRACT The use of engineered timber has redefined the possibilities within timber construction, particularly in the case of glued laminated timber. This is due to its optimised structural values and integrity. In many ways glulam has begun to replace other materials, especially some timber products. Glulam products can be made to almost any length and the timber structure is not limited by the height of the original tree. Smaller trees can be harvested and then laminated making a structural element, equal to or longer than that of the original. Additionally, glulam has greater strength and stiffness compared to a timber member of the same size, meaning greater distances can be spanned with less need for intermediate supports. This means that within designs, glulam allows for greater versatility and span, enabling for more intricate and unique designs. Due to the capabilities offered by glulam, there are further opportunities available as to where this type of engineered timber can be used. I aim to investigate and demonstrate the capabilities of glulam structurally and its capabilities as a constructional material through case studies. Furthermore, I question what this has meant to the timber construction realm, changes to the industry and a change in views in the industry. Lastly, I also investigate the sustainability of glulam as a material and its environmental impact. This dissertation is presented in the form of a materiality information booklet; on the essential â&#x20AC;&#x2DC;need to knowâ&#x20AC;&#x2122; information on glue laminated timber.

TABLE OF CONTENTS Introduction Structural Capabilities Small Scale Post & Beam Case Study Large Scale Post & Beam Case Study Large Scale ‘Node Grillage’ Case Study Glulam in Industry Sustainability Conclusion

Introduction

15 Materiality can be defined as “the quality of being composed of matter”1; within architecture it is seen as a conceptual idea of the use of materials in the medium of construction. This abstract idea of using materiality through concept, is to depict and envisage an image of what the overall design scheme will be; aesthetically as well as structurally. Materiality choices define how the building will stand up and appear, which is integral to the design choices within architecture to ensure an inhabitable success, as a building, able to hold its structure as well as create a desirable atmosphere. Within this architectural subject, timber use holds a large share. It is one of the most traditional building materials and has been used for centuries. Signs of its use in construction can be found dating back to the beginning of civilisation, and “the techniques used in timber framing date back to Neolithic times, and have been used in many parts of the world…”2 Within the modern age the desire to use timber is still present, however its capabilities are not up to the needed strength or span due to its reliance on the capabilities of nature and natural growth. The result of this is the development of prefabricated and engineered timber, which has allowed for the elaboration of many products fit for Oxford Dictionaries, Materiality (UK: Oxford University Press, 2014) <http://www.oxforddictionaries.com/definition/english/materiality> [accessed 5 January 2015] 2 J. H. Williams, Roman Building-Materials in South-East England, Britannia, Vol. 2 (UK: Society for the Promotion of Roman Studies, 1971), p. 168 1

16 constructional purposes, such as glue-laminated timber. Glue-laminated timber has conquered some of the issues associated with using timber by improving it as a product through engineering. Glue laminated timber has been named ‘glulam’: “The term ‘glulam’, used as an abbreviation for glued laminated-timber structures…”3. “Glulam technology was developed in Germany at the end of the nineteenth century and the world’s oldest glulam factory, Töreboda in Sweden is still in use today.”4, this begins to hint at how glulam is a well-established industry and is expanding. The production of glue-laminated timber has been described as: “glulam members are fabricated from relatively thin laminations…of wood. These laminations can be end-jointed and glued together in such a way to produce wood members of practically any size and length.”5

W. A. Chugg, Glulam: The Theory and Practice of the Manufacture of Glued Laminated Timber Structures (London: Ernest Benn Ltd. 1964), p.1 4 European Wood, Glulam Construction (China: European Wood, n.d) <http://www.europeanwood.org.cn/en/glulam-construction> [accessed 5 January 2015] Modern Glulam Technology 5 Donald E. Breyer and others, Design of Wood Structures – ASD/LRFD (USA: McGraw-Hill, 2007), p.5.1 3

17 “Wood is one of the oldest construction materials in the world. Buildings, bridges and ships have been built in timber for many centuries. No other material has such a wide range of uses. Glulam – glued laminated timber – opens up still further possibilities for wood building technology.”6 Due to the opportunities created by the use of glulam, in some settings glue laminated timber has begun to replace traditional timber.

Glulam is stronger,

more flexible and “also has a better strength to weight ratio than steel.”7 These factors have contributed to an increase in the usage of glulam, so much so that it has slowly started to replace timber, as glue laminated timber allows for greater spans and bears larger loads whilst keeping a timber aesthetic. The use of glulam within the construction industry has allowed larger and more intricate designs to be made, fuelling an increase in popularity and a change in views on the use of glulam. “It also means architects and engineers have virtually unlimited possibilities when designing their own constructions in glulam, whether the task is a small house, the roof of a department store or a road bridge.”8 Glulam is a versatile construction material and as a result it has seen a rise in popularity and an increase in usage. Overall it can be said that the European Wood, Modern Glulam Technology Ibid. Modern Glulam Technology 8 Ibid. Modern Glulam Technology 6 7

18 use of glulam has somewhat re-popularised timber due to its new ability to do more as an engineered product. As glulam use has increased, so further design experimentation and product research are being put into it to improve its structural integrity and permit the creation of more dynamic designs. As an engineered timber product, engineers and conceptual designers create designs and test the material, generating something unique and testing its capabilities in a structural setting. The use of glulam in construction has also increased peopleâ&#x20AC;&#x2122;s interest in the product: as understanding of its structural capabilities is expanded, so it is increasingly used and seen in different constructions. As a result there is an increase in the knowledge and awareness of this engineered product, especially by the appearance of glulam structures being advertised on the television through certain architectural design programmes, showing different ways in which glulam can be used to create the design intended; further promoting glulam. Overall, glulam as an engineered timber product has enabled timber to be used, but in a more modern setting through keeping timberâ&#x20AC;&#x2122;s aesthetic but improving its structural capabilities. Glulam can be used in traditional timber style but its impact comes in an ever-expanding application to contemporary design. To investigate glulam as a material, various factors are considered in the

19 sections below: its abilities as a structural material; how it performs in the industry; and its sustainability. Additionally contrasting case studies of a large and small scale will be discussed to illustrate the various ways in which glulam can be used, further proving the versatility of this material; structurally and aesthetically.

Structural Capabilities

23 Glue-laminated timber as a structural material can be defined as “…the use of an adhesive and thin layers of timber to make a structural member…”9, which are the components used to make up glulam. “The earliest still-standing glulam roof structure is generally acknowledged to be the assembly room of King Edward VI College…Southampton, England, dating from 1866, designed by Josiah George Poole.”10 Glulam can be made up of softwoods or hardwoods, however “soft woods are usually adopted for glulam construction in the UK…”11, most commonly “…structural glulam members are produced using Douglas Fir or Southern Pine. Hem-Fir, Spruce-Pine-Fir, Alaska Cedar, and various other species including hardwood species can also be used.”12 The next component that needs to be considered within glulam is the adhesive, “traditionally, two types of glue have been permitted in the fabrication of glulam members: (1) dry-use adhesives (casein glue) and (2) wet-use adhesives (usually phenolresorcinol-base, resorcinol-base, or melamine-base adhesives.)… Today only wet-use adhesives

W. A. Chugg, p.xix A.G.K Leonard, Journal of the Southampton Local History Forum (Southampton: Southampton City Council, 2008), p. 20 11 H. E. Desch & J. M. Dinwoodie, Timber: Structure, Properties, Conversion, and Use ,7th edn (London: Macmillan Press Ltd. 1996), p. 200 12 Donald E. Breyer and others, p.5.4 9

24 are permitted in glulam manufacturing, according to ANSI/AITC 190.1-2002”13 This change is because “wet-use adhesives…can withstand severe weather conditions.”14 so therefore are more desirable in a structural setting. Within this heading, there are a variety of adhesives to choose from, most of these are formaldehyde based but this has a negative environmental impact, so therefore it is best to use alternate adhesive products, for example Purbond® HB E (which) is a one part, moisture reactive polyurethane. These components are assembled through the method of arranging “a number of laminations…parallel to the axis of a member, the individual boards comprising the laminations, being assembled with the grain approximately parallel and glues together to form a member which functions as a single structural unit.”15 Due to the way in which glulam is made the size and rigidity can be manipulated, as “…it can be tailor made to fit both the load requirements and the design of the structure: thus the architect is provided with a greater degree of freedom in the use of laminated beam construction than traditional wood or steel joists.”16 This is enabled by the way in which glulam is manufactured, as “timber layers, normally 43mm thick, are glued together to build up deep beam

Donald E. Breyer and others, p.5.8 Donald E. Breyer and others, p.5.9 15 W. A. Chugg, p.1 16 H. E. Desch & J. M. Dinwoodie, p. 200 13 14

25 sections. Long sections can be produced by staggering finger joints in the layers.”17 Finger joints are a “…glued connection between the edges of two boards which have a shape similar to a hand.”18 This shows an advantage to using glulam, as “the growth characteristics that limit the structural capacity of a large solid sawn wood member can simply be excluded in the fabrication of a glulam member.”19 The only restrictions tend to be that the “lengths of the glulam members are limited by handling systems and length restrictions imposed by highway transportation systems rather than by the size of the tree.”20 The method of glulam manufacture is through the following sequence: 

Timber selected as possible viable glulam structural member options



Drying the timber Normally kiln-dried. “Softwood boards are dried down to a moisture content of approx. 12% and then planed”21 This is important as it can affect the bond strength and glulam stability.

Fiona Cobb, Structural Engineer’s Pocket Book (Oxford: Elsevier, Butterworth Heinemann, 2004), p. 120 18 HESS Timber, Production of Glulam Wood (Kleinheubach, Germany: HESS TIMBER, 2010) <http://www.hess-timber.com/en/brettschichtholz/technische_infos/herstellung/> [10 January 2015] 19 Donald E. Breyer and others, p.5.5 20 Donald E. Breyer and others, p.5.1 21 HESS Timber, Production of Glulam Wood 17

26 

Stress-graded Through visual or mechanical tests, ensuring a set structural grade is met



Removing knots and defects (inspection for weaknesses) “…before these are made into laminations…replace the defects with clear, straight-grained timber. This operation is known as ‘patching’” 22 or timber lengths with defects are removed entirely



Plane-ing the boards Planed to a maximum thickness of 45mm, and cut to the required length



Adhesive spread on the faces of the laminations



Cramping Jigs used to apply pressure and the shape required to manufacture the wanted profile



Further plane-ing of the laminations Planed to the size, and remove any escaped glue, to clean up the member



Bond strength tested Through the application of pressure



Final processing This involves final appearance checks, quality control, post preservation treatment if required, and fire-retardant treatment

W. A. Chugg, p.40

27 From the way glulam is engineered, it has certain structural capabilities and abilities as a material. Within glulam the “glue lines are very thin. The portion of glue in a glulam member is less than 1%.”23 The adhesives and timber used is stress-graded and tested to ensure that the glulam members will perform as predicted and intended. “…Its permissible bending strength is up to 80% higher than the permissible bending strength of the usually used solid-wood. As a result of the productionprocedure glulam members are deformed less through shrinkage and have a higher resistance to cracking.”24 This increased strength and resistance to cracking permits glulam to be manipulated to create a variety of forms. “…Single lamellas are very flexible unless bonding together, it is very easy to produce curved glulam members. Spatially curved of twisted members require greater efforts. “ 25 Despite the difficulty and engineering behind this, glulam can out perform other materials structurally by displaying its ability to be versatile and create unique, intricate forms.

HESS Timber, Production of Glulam Wood Ibid., Production of Glulam Wood 25 Ibid., Production of Glulam Wood 23 24

Glulam can be incorporated into various structures and can be used within conventional structural settings, such as post and beam architecture, where longer spans are required or where heavy loads will be applied. Alternatively, glulam can also be used to create a latticed structure in a webbed, interlocking form to create a cross linked, large spanning construction. Glulam can also be used in small-scale or large-scale designs. Generally, in smaller constructions, glulam is used where appropriate and to bear heavy loads. While, larger constructions use this material to load bear and span larger areas, applying glulam to the best of its abilities and taking advantage of its strength and longer lengths. In all glulam constructions the option is available to keep the natural timber aesthetic and this is often celebrated through structural exposure.

29 The Glue Laminated Timber Association summarises glulam applications in a series of ‘case studies’ as follows: “

∘ beams and posts ∘ trusses and girders ∘ portals ∘ arches ∘ domes ∘ three dimensional frames ∘ bridges

”26

Glulam is a preferred material to use due to its “…favourable strength-toweight ratio and high flexibility of wood compared with other materials render it is an attractive means of bridging large spans, whether in the form of a bridge or the supporting system of a large roof.”27 This strength is due to the engineered nature of this product and is enhanced by “…combinations of laminations. These two types are bending combinations and axial combinations.”28 Glulam members “…are usually loaded in bending about the strong axis of the cross section. Large section properties and the distribution of laminations over the depth of the cross

Glue Laminated Timber Association, Glulam – Case Studies (GLTA, n.d) <http://www.glulam.co.uk/caseStudies.htm [accessed 5 January 2015] 27 H. E. Desch & J. M. Dinwoodie, p. 200 28 Donald E. Breyer and others, p.5.11 26

30 section make this an efficient use of material.”29Any weaknesses within the material are supported as “…laminating optimises material use by dispersing the strength-reducing defects in the laminating material throughout the member.”30; meaning that there aren’t weak spots and there is a more even stress distribution. “…maximum bending compressive and tensile stresses are equal, research has demonstrated that the outer laminations in the tension zone are the most critical lamination in a beam. For this reason, additional grading requirements are used for the outer tension laminations.”31 “In addition to grading for strength, glulam members are graded for appearance. One of the four appearance grades (framing, industrial, architectural, and premium) should be specified along with the strength requirements to ensure that the member furnished is appropriate for the intended use.”32 The appearance grade does not affect the strength of the product, however it can have a direct impact on the cost as more quality checks and aesthetic pieces of timber with few defects will have to be chosen. This

Donald E. Breyer and others, p.5.7 Ibid., p.5.5 31 Ibid., p.5.6 32 Ibid., p.5.11 29 30

31 demonstrates that glulam can meet an aesthetic need in a structural element, as well as offering physical capabilities. The material thus offers the architect the option of designing atmospheric spaces along with structural elements to create an effective, inhabitable building. Compared to other materials, glulam in many ways is competing or replacing other constructional materials. It is most noticeable in the context of timber, as glulam has improved the natural product into an engineered piece. This has improved on the qualities that timber provides; one of these being strength, as glulam is able to bear larger loads due to its laminations. Additionally, this engineered timber is also able to span greater distances, due to finger joints and because it is not bound by natural growth. However, glulam does cost more than timber, but this can be tackled by allowing both products to work together; only using glulam where it is needed. For all of the advantages of using glulam, this engineered product has a timber aesthetic so a natural feel can be kept, which in some designs is desired architecturally.

34 34

Stratalam, NZ Engineered Glulam, Span Tables (New Zealand: Stratalam, n.d.) <http://www.stratalam.co.nz/_resources/StratalamSpanTables.pdf> [accessed 12 January 2015] p.6 34 Ibid., p.6 33

33 Glulam has also retained the fire retardant properties that natural timber contains. The positive fire retardant quality that timber offers, glulam has been engineered to keep. This is a positive quality, as when timber burns the outside becomes charcoal to try and protect the inner material; this therefore slows down the burning rate and reduces the likelihood of structural failure. It is generally known within construction that “buildings constructed with large structural timbers have excellent fire-resistive qualities.”35 This is unlike steel, which if not protected and fire proofed, deforms and melts once the building has hit certain temperatures. This obviously can create a very dangerous environmental setting due to structural failure. Timber constructions do, however, have to follow codes to ensure “…fire resistant timber structures.”36, these include Heavy Timber Construction, and Fire Resistive Construction. The first, “Heavy Timber Construction has long been recognized by the model building codes as fire resistant. To meet the requirements…limitations are placed on the minimum size, including depth and thickness, of all load-carrying wood members.”37 This is set out “…in AITC 113 Standard for Dimensions of Structural Glued Laminated Timber.”38 Additionally, Fire Resistive Construction should be considered as it states “…the amount of time a structural member can support its AITC, Glulam: Engineered Strength. Unsurpassed Versatility. Dependable Quality (USA: AITC, 2007) <http://www.aitc-glulam.org/glulam.asp> [accessed 5 January 2015] 36 Ibid., Fire Performance 37 Ibid., Fire Performance 38 Ibid., Fire Performance 35

34 load before collapsing.”39 These guides and codes ensure quality and safety within construction, and set out the limits and the necessary information needed for structural fire protection. Overall, “when subjected to fire, larger timber sections have greater resistance to loss of structural integrity than steel or prestressed concrete. … Due to the inherent material properties of this natural building material, the fire-resistance characteristics of wooden structural members are excellent.”40 The life span of glulam “can be considered virtually unlimited. The use of modern phenolic synthetic resin adhesives also ensures an indefinite life for the bond between the laminations.”41 The threats to its unlimited service can be affected by onsite changes to the engineered timber member, particularly if it is preservative-treated after gluing. However, this can be avoided by ensuring the correct dimensions are ordered to “eliminate penetrating the treatment envelope by post-treatment cutting and drilling and help ensure long life of a member.”42 Additionally, care should be taken to repair and protect a member AITC, Fire Performance – Fire Resistive Construction HESS TIMBER, HESS TIMBER Company Brochure (Kleinheubach, Germany: HESS TIMBER, 2013)<http://www.hess−timber.com/downloads/prospekte/en/HESS_TIMBER_Compa ny_brochure.pdf?PHPSESSID> [accessed 10 January 2015] p.5 41 Glue Laminated Timber Association, Specifiers Guide (GLTA, n.d.) <http://www.eximcorp.co.in/images/products/glulam/glulam-specifiers-guide.pdf> [accessed 5 January 2015] p.10 42 APA – The Engineered Wood Association, Glulam: Product Guide (USA: APA, 2008) 39 40

35 during its lifespan, as well as maintenance checks. Another risk “…is a rise in moisture content to more than 22%-25% for prolonged periods.” 43 This however, can be tackled by attempting to avoid designing spaces in which water would be caught and so ensuring there are no moisture traps, along with providing ventilation. Therefore glulam can survive for at least the length of a human life. Compared to timber, structurally, glulam is more capable and a stronger constructional component that can be well used within this industry. “The high strength and stiffness of laminated timbers enable glulam beams and arches to span large distances without intermediate columns. This translates to larger rooms and more design flexibility than with traditional timber construction.”44; therefore giving the designer more freedom and different design space options. To use glulam to the best of its ability, it should be appropriately used, within the applicable Codes, and maintained to ensure a safe structure.

<https://law.resource.org/pub/us/code/bsc.ca.gov/sibr/org.apawood.X440.pd> [accessed 10 January 2015] p.23 43 Glue Laminated Timber Association, p.10 44 AITC, Glulam: Engineered Strength. Unsurpassed Versatility. Dependable Quality – Strong

Small-Scale Post & Beam Architecture

39 Glulam has been commonly used in small-scale construction, where glulam beams have been used to replace traditional timber beams. This generally occurs when a greater load bearing capacity or span is needed. Glulam beams have enabled larger spans before the need for supportive columns; therefore allowing wider openings within this particular type of structure. Small-scale glulam constructions often consist of glulam as a structural material for roof structures within conservatories. This also shows how glulam is being used in a mass market and not just for big budget construction briefs. To look at this in more detail, an orangery constructed by the business David Salisbury will be investigated to see how glulam can be put to use and to also look at glulam’s capabilities in a real setting. David Salisbury is a “bespoke conservatory or orangery” 45 company, where their “dedicated team works closely with you to ensure your conservatory becomes a flawless addition to your home.”46According to the brochure, they state, “the joy of working with timber is that it is an entirely flexible product with an inherent quality and universal appeal. … Timber can be traditional, with that sense of solid permanence we all recognise; or modern, sleek, striking, and

David Salisbury, About Us (UK: David Salisbury, 2015) <http://www.davidsalisbury.com/about-us> [accessed 11 January 2015] 46 David Salisbury, Working in Harmony 45

40 bold.”47 They create bespoke designs with designers who come on site and create a detailed brief of the requirements and “…take inspiration from the architecture of your house.”48 This particular conservatory business focuses on the use of timber in construction. Glue laminated timber is used when needed and where appropriate within their designs.

David Salisbury, Working in Harmony (N. Yorkshire: David Salisbury, 2014) p.35 Ibid. p.58 49 David Salisbury, Elevation of Conservatory – 83941-Q2 (N.Yorkshire: David Salisbury, 2014) 47 48

41 To exemplify how glulam can be used in small-scale constructions, an orangery by David Salisbury will be investigated. The design was created as an extension to a house in North Yorkshire in 2014. The dimensions of the space designed are 5.1 meters by 5.2 meters. The structural materials used for this design is predominantly timber. However, for the roof construction, glulam was used to span across this space, supporting an opening within the centre to hold a large roof lantern. The dimensions of the roof lantern are 2.4 meters by 4.4 meters. These glulam beams are used to support a flat roof with a central rectangular opening, consisting of the roof lantern that rises above the roof level and creates a small-pitched roof above.

David Salisbury, Perspective Plan Overview â&#x20AC;&#x201C; 83941-Q2 (N.Yorkshire: David Salisbury, 2014)

F. Graham, Original Image of Designed Conservatory (N.Yorkshire: 2015)

44 This case study shows how glulam can be used in small-scale buildings. Glulam is only needed if a timber construction is desired but a large load bearing capacity is needed. Glulam is particularly used in conservatories, as it has a less engineered aesthetic, strongly resembling timber but has a greater engineered strength. When using glulam in small-scale buildings it is important to only use it when appropriate as glulam costs more than timber, and in this type of construction budgets are generally smaller. There is no need to use glulam when a standard timber member would be appropriate. As the structures are smallscale often timber of shorter lengths than that offered by glulam is sufficient. Overall, in small-scale construction, it is important to ensure that glulam is only used when appropriate, for example when a larger span and timber aesthetic is required, and also used to the best of its ability to ensure a successful structural outcome.

Large-Scale Post & Beam Architecture

47 Glulam is becoming more popular in large-scale constructions. Timber is often not the material of choice when considering large-scale structures, however, engineered timber allows this to become a possibility. Glulam can be used to create longer posts and beams as the laminations are produced by finger jointing smaller pieces of timber together so that long, strong lengths can be created. This has opened up an opportunity within large-scale construction, as now there is an alternate material choice that has a natural aesthetic. A building that shows this is architect Shigeru Banâ&#x20AC;&#x2122;s, Tamedia Office Building in Zurich, which was constructed in 2013.

53 53

Didier Boy de la Tour, Tamedia Office Building / Shigeru Ban Architects (ArchDaily, 2014) <http://www.archdaily.com/478633/tamedia-office-building-shigeru-ban-architects/> [accessed 10 January 2015]

48 The Tamedia Office Building, consists of a “10,120 square meter”54 area, and “…has the possibility of developing almost 165 feet of façade…”55 According to Shigeru Ban’s official online works website, which states that: “From an architectural point of view one of the main features of the project is indeed the proposition of a main structural system entirely designed in timber where its innovative character from a technical and environmental standpoint, gives the building a unique appearance from the interior space as well as from the surrounding city. In order to reinforce and express this idea the building skin is entirely glazed…”56 Ban’s design is an intriguing structure to investigate, as it was one of few multi-storey glulam constructions. The structural system is made up of glulam “columns 21 meters in length and 440 mm x 440mm in section.” 57 Within the interior, the structural elements are exposed, which promotes a celebration of timber aesthetic by allowing the glulam to be visible. The building is then sealed ArchDaily, Tamedia Office Building / Shigeru Ban Architects (ArchDaily, 2014) <http://www.archdaily.com/478633/tamedia-office-building-shigeru-ban-architects/> [accessed 10 January 2015] 55 Shigeru Ban Architects, Tamedia New Office Building (Shigeru Ban Architects, 2013) <http://www.shigerubanarchitects.com/works/2013_tamedia-officebuilding/index.html > [accessed 10 January 2015] 56 Idib. 57 Steve Dudek, Shigeru Ban Lecture, Newcastle University, slide 5 54

49 from the exterior elements by a glass façade, which allows the structural system to also be seen from the external spaces. This is backed up in the ArchDaily, which has documented the architect’s work, through the statement that “…the fact that the structural elements are entirely visible also gives a very special character and high quality spatiality to the working atmosphere.” 58 This innovative design considers the architectural atmospheric aesthetics and the technicalities behind structural design, as well as using an environmentally sustainable approach.

60 59

ArchDaily, Tamedia Office Building / Shigeru Ban Architects Didier Boy de la Tour, Technology: Seven Storey Wood Office Buildings in Zurich (Detail Inspiration, 2014) <http://detail-online.com/inspiration/technology-seven-storeywood-office-building-in-zurich-108958.html> [accessed 10 January 2015] 60 Didier Boy de la Tour, Tamedia Office Building / Shigeru Ban Architects (ArchDaily, 2014) 58 59

50 The structural system used within this design is a series of portal frames, which allows for openings within the construction of bays. Within this type of system, the space can be left open with the columns interjecting into the space, or intermediate walls can be installed to connect the columns and seal the space. This office building consists of singular 5-storey high glulam columns, measuring 21 metres in height; showing how glulam members can be made to the desired length beyond that of traditional timber. Within a lecture on Shigeru Banâ&#x20AC;&#x2122;s design, Steve Dudek shows how Ban has tackled some engineering issues with using timber as a material: â&#x20AC;&#x153;To span 11 metres with timber in a non domestic building is a problem, Ban solves this by employing a pair of beams sandwiching the main column, the beams are 550mm deep and are themselves made from two 120mm wide glulam sections. An oval glulam bar 240/350 mm connects the frames.â&#x20AC;?61 This shows how glulam was used to the best of its abilities and the structural techniques and details that have been put to use within the construction of this design. Working within this particular aesthetic aim, glulam was the only material, which could have achieved the needed structural requirements.

Steve Dudek, Shigeru Ban Lecture, Newcastle University, slide 7

6263

The most unique trait of this design is the way in which the whole Dudek, “…Ban was not having any structural steel connectors in his design.”64 Shigeru Ban has conquered this through using “…locking pin connections milled with extraordinary precision…”65 This technique was used as one of Ban’s design aims was to build the entire design structure out of timber, “…similar to traditional Japanese timber buildings.” 66 This came down to the smallest of details, including the joint connections, which have been made from timber. An example of this is the use of “…special dowels made of beech plywood serve for load

Shigeru Ban Architects, Tamedia Office Building / Shigeru Ban Architects (ArchDaily, 2014) Didier Boy de la Tour, Tamedia Office Building / Shigeru Ban Architects (ArchDaily, 2014) 64 Steve Dudek, Shigeru Ban Lecture, Newcastle University, slide 4 65 Detail Inspiration, Technology: Seven Storey Wood Office Building in Zurich (Detail Inspiration, 2014) <http://detail-online.com/inspiration/technology-sevenstorey-wood-office-building-in-zurich-108958.html> [accessed 10 January 2015] 66 Ibid. 62 63

52 transmission and reinforcement of construction components.”67 Overall, this shows the great level of detail applied to ensure a predominantly timber design and the effort of engineering invested. Within this design, Ban has also considered the sustainable aspect of the use of the timber product, glulam. This has been done through “…the clear contribution to sustainability on the choice of timber as the main structural material (only renewable construction material and the lowest C02 producer in construction process)”68 On the whole, Shigeru Ban has achieved his aim of creating a predominantly timber structure through the use of glulam. The building successfully illustrates how glulam can be used in large-scale post and beam architecture. The use of glue-laminated timber demonstrates the material’s ability to create an open space and its exposure retains the atmospheric aesthetic of a timber construction. In this design form, glulam can be compared to steel. However, if steel had been used, the material would have to be boxed in or alternatively coated in 67 68

Ibid. ArchDaily, Tamedia Office Building / Shigeru Ban Architects

53 fire retardant paint. In either case it would ruin the effect and the aesthetic created by using a timber construction could not be replicated. Similarly, the environmental benefits of using a material produced from renewable resource (timber) with low carbon emissions during manufacture could not be achieved had steel been used. Shigeru Ban’s Tamedia Office Building shows the abilities of glulam and how the “Planning and realization of this ambitious project were a great challenge for the timber engineers and builders” 69 but have paid off through the creation of an intricate, unique piece of timber construction, which celebrates and exposes the use of glue-laminated timber. 70

Detail Inspiration, Technology: Seven Storey Wood Office Building in Zurich Didier Boy de la Tour, Tamedia Office Building / Shigeru Ban Architects (ArchDaily, 2014)

Large-Scale ‘Node Grillage’ Architecture

57 As an alternative to post and beam architecture, glulam is also used in “egg box” designs. An example of this is the Canary Wharf Crossrail Station, London, designed by Foster + Partners. This case study shows the versatility of glulam and how it can be used within a variety of structural systems. The architects used glulam due to a conceptual materiality choice as “the wooden structure evokes the ships that once sailed into West India Dock.”71 Through doing so “the architects Foster & Partners, with Arup Engineers, have employed around 1500 glulam members with a maximum length of 9.0 m in another ‘node grillage’ roof…”72 “A 310-metre-long latticed spruce timber roof wraps around the building above the ground. Spaces in the lattice are either filled with transparent cushions of air made using ETFE plastic, or edged with aluminium panels.”73 The “…roof arches 30 metres over the park and stretches around the shops and entrances

Foster + Partners, Projects/Canary Wharf Crossrail (London: Foster + Partners, 2015) <http://www.fosterandpartners.com/projects/canary-wharf-crossrail/> [accessed 11 January 2015] Description 72 Glue Laminated Timber Association, Glulam – Performance Record: Recent History and Contemporary Trends (GLTA, n.d) <http://www.glulam.co.uk/performanceTrends.htm> [accessed 5 January 2015] The future - maturing of the sustainability cachet – growing market share 73 Dezeen Magazine, Foster’s Canary Wharf Crossrail station near completion (Dezeen Magazine, 2014) <http://www.dezeen.com/2014/07/14/fosters-canary-wharf-crossrail-trainstation-nears-completion/> [accessed day 11 January 2015] 71

58 below.”74 This shows the large scale of this design. To create such a sizeable structure “the design of the lattice is a fusion of architecture, engineering and sophisticated three-dimensional modelling.”75 This shows the time and effort engaged to create the desired outcome.

Foster + Partners, Projects/Canary Wharf Crossrail - Description Ibid, Projects/Canary Wharf Crossrail - Description 76 Ibid., Projects/Canary Wharf Crossrail 74 75

59 The structural elements within the design, utilise glulam members, however: “…despite the smooth curve of the enclosure, there are only found curved timber beams in the whole structure. To seamlessly connect the straight beams, which rotate successively along the diagonals, the design team developed a system of steel node, which resolve the twist…”77 This shows the way in which the glulam beams have been put to use within this large-scale construction. “The spruce glulam beams are sustainably sourced and support ETFE cushions, which are filled with air and lighter than glass.” 78 showing how in this case glulam has been put to use for it’s spanning capacity and ability to be manipulated into the desired form. Within the roof structure the large-scale of the construction puts pressure on the glulam members due to the intricate roof design and glulam used in this manner can’t always support large loads due to the load already imposed by the structural system. “Where cushions are removed, the timber is protected by aluminium flashing. Further developing an approach pioneered in the flowing glass roof.”79

Foster + Partners, Projects/Canary Wharf Crossrail – Description Ibid., Projects/Canary Wharf Crossrail - Description 79 Ibid., Projects/Canary Wharf Crossrail - Description 77 78

60 The design of the Canary Wharf Crossrail Station, features a large spanning timber glass roof. The architecture and engineering of this design have led to decisions to use glulam, creating a timber construction, which would not have been possible without engineered timber.

This case once more

demonstrates how glulam has opened up new opportunities for timber construction and again illustrates the versatility of glulam as a constructional material, resulting in an intriguing design.

Foster + Partners, Projects/Canary Wharf Crossrail - Description

Glulam in Industry

63 Glue laminated timber is used in the design process as a constructional material and as an aesthetic form. Glulam is an ideal choice of material to use within the structural details of a design due to its strong mechanical performance. However, there is more to this particular type of engineered timber. These qualities include a natural timber appearance, which can be the desired effect within a space either internally and/or externally. This eliminates the need for cladding and other techniques to hide unappealing materials. Glulam creates an attractive aesthetic allowing the structure to be left exposed and to be celebrated. Due to the nature of this engineered timber product, there is a great deal of versatility in how it can be used within a design. Therefore it is a desirable material to use. Glulam has been developed and tested in different settings to explore its capabilities as a material and where it can be used appropriately. â&#x20AC;&#x153;The timberlaminating industry in Britain wasâ&#x20AC;Śencouraged by substantial orders for laminated marine sections placed by the Admiralty early in the 1950s.â&#x20AC;? 81 This resulted in a helpful kick-start to the industry in Britain. Glulam is now a commercial product and used in a variety of construction projects: residential, commercial, industrial, and so on. In fact, glulam use has an opportunity to

W. A. Chugg, Glulam: The Theory and Practice of the Manufacture of Glued Laminated Timber Structures (London: Ernest Benn Ltd. 1964), p.xix

64 expand. There is an opportunity for glulam to be used as commonly as other products especially when its strength and structural capabilities are considered. There is a gap in the market for glulam as a timber product, with aesthetic possibilities, longer spans and stronger load bearing capabilities. Its structural strength and sustainable advantages of being a renewable source mean that it can be more commonly used. Glue laminated timber can be used over other materials with its strength, environmental and aesthetic advantages. This has already begun in some cases where glulam has replaced the use of timber and other materials. It has stronger load bearing capabilities than traditional timber beams and is able to cover and support longer spans within a structure. However, glulam can be more expensive than timber to purchase so it should only be used where it is needed and not where normal timber pieces could be used. It is important that glulam is only used in appropriate situations, specifically where a stronger, more structurally advanced product is needed. The advantages of glulam have led to an increase in its use. It had a slow start in some countries but took off in others. â&#x20AC;&#x153;Although the system of laminating originated in Germany, the industry does not appear to have developed there to

65 any extent.”82, observed in W. A. Chugg in 1964. However, today Germany has some of the leading glue laminated timber producers in Europe. This includes HESS TIMBER, “…one of Germany’s and Europe’s technical leaders in timber construction”83, producing vast amounts of standardised or customised glulam components. “Perhaps the countries with the largest glue laminated timber industries are USA and Canada and … that some thirty years elapsed between the development of the industry in Europe and the commencement of production in the USA.”84 North American glue laminated timber producers have grown rapidly and are now competing in European markets. “Structural glued laminated timbers have been used successfully in the United States for more than 70 years. In Europe, glulam has been used successfully for more than 100 years.”85 European and North American producers have expanded throughout this time, encouraging further development and creating unique forms, resulting in an intriguing and diverse glulam product range.

W. A. Chugg, p.xix HESS TIMBER, HESS TIMBER Company Brochure, p.2 84 W. A. Chugg, p.xix 85 AITC, Glulam: Engineered Strength. Unsurpassed Versatility. Dependable Quality 82 83

66 Glulam production has also expanded globally, â&#x20AC;&#x153;structural members are today produced in a large number of countries and factories have been established in South Africa, Finland, India, New Zealand, USA, Canada, British Isles, Belgium, Holland, Australia, and Japanâ&#x20AC;Śâ&#x20AC;?86 and more since then and is ever expanding. The engineered wood industry has grown progressively: the benefits of glulam have raised demand from the construction industry and as demand has grown so has production and the product range offered. As the glulam product has evolved so has interest grown for its use within the construction and architectural design industry. Today, there are engineered timber production companies that focus on mass production and on smaller businesses that create specialised products. Within architecture the use of glulam has become more popular. Architecturally glulam has become much more widely accepted and used as a building material, as it has strong load bearing qualities and is also able to be produced in intricate, unique forms. Glulam has been manipulated and constructed to fit to the given architectural design brief and to create the intended design. An example of this can be seen at the Crossrail Station in Canary Wharf, London, where: 86

W. A. Chugg, p.xix

“A translucent “green space” linking to the local community was the key to the brief… Because of the great length – 256 m - of the timber gridshell canopy, with a span of approximately 30 m, this is expected to become one of the largest glulam structures in the UK. The architects Foster & Partners, with Arup Engineers, have employed around 1500 glulam members with a maximum length of 9.0 m in another “node grillage” roof… It seems that the message regarding all of the benefits and capabilities of timber construction is now being received more widely by the UK construction industry and glulam will continue to enjoy a growing share of this trend.”87

Glue Laminated Timber Association, Glulam – Performance Record: Recent History and Contemporary Trends (GLTA, n.d) <http://www.glulam.co.uk/performanceTrends.htm> [accessed 5 January 2015] The future - maturing of the sustainability cachet – growing market share

Cross Rail, Canary Wharf Station (London: Cross Rail, n.d.) <http://www.crossrail.co.uk/route/stations/canary-wharf/> [accessed 12 January 2015]

69 In this piece of architectural concept and design, the architects and engineers have experimented with ways to push glulam as a structural material. This shows willingness by the industry to test different structural techniques and glulamâ&#x20AC;&#x2122;s ability to respond: permitting for more unique and extensive forms to be created. These opinions express how glulam is utilised and its ease of utilisation. These support the popularity of the product. Perceptions of glulam by various members in the construction industry are an equally important consideration as its structural capabilities. If people dislike using a product, the product will most likely not be put to use despite its benefits. Within the construction industry, glulam is a popular and an acceptable material to use in various circumstances offering benefits of structural strength, environmental sustainability, good aesthetics and ease of use. It is also flexible, permitting architects and engineers to experiment with pushing a product to its limit and seeing what it is capable of achieving within a structural setting. The popularity of glulam can also be demonstrated by its sales figures and production levels, as it reflects the demand for the product in the market. In the USA there has been an increase in glue laminated timber production from 2009

70 to 2013. In 2009 the production levels came to “256, 900 cubic meters” 89, which increased to “353,800 cubic meters”90 in 2013. Within this four-year period, production increased by close to 38%, showing how the industry is growing in a smooth and positive manner. “The statistic … provides a forecast for 2014” 91, which is “375,400 cubic meters”92 showing a further increase. This production increase can also be seen in other countries across the world. Furthermore, the increase in these figures proves glulam’s success as a material within the construction market.

Statista, U.S. Glulam Timber Production 2009-2013 (Statista, n.d) <http://www.statista.com/statistics/238006/us-glulam-timber-production/> [accessed 10 January 2015] 90 Ibid. 91 Ibid. 92 Ibid. 89

71 93

Statista, U.S. Glulam Timber Production 2009-2013

“The use of glulam in the construction industry continues to expand and to find new directions”94 according to the Glued Laminated Timber Association. The GLTA goes onto further depict that the glulam industry can be somewhat generalised into three blocks according to their characteristics, these are: “∘ Buildings, often for accommodation, containing glulam… -

These include other materials …

∘ Buildings that are achieved entirely by timber systems… ∘ Customised solutions of architectural distinction…”95 There are also other situations that do not fit within these categories, however a vast majority do and show how glulam has been modified to cater for the mass market or for individual needs, showing its versatility. The increase of glue-laminated timber also reflects the increased number of applications where it is being used as described in the Structural Capability Section.

These applications show how glulam is being widely accepted and used as a building material fit for constructional purpose, especially for intricate, long spanning designs. Glulam is also for more specialised applications, for example, it is often used to house indoor swimming pools, in particular the roof structure. In additional to the need for long spans, the process treatment and compounds within glulam can withstand the damp atmosphere created in these buildings. The method and outputs of architectural design have also been influenced by the use of glulam and its ever-expanding industry. Designs have been created not just of standardised lengths and forms but also more specialised products. Glulam has the capability to be applied to span greater distances and also to be manufactured into different forms, arches, and bends. As an engineered product, glulam can be formed into new designs with little limitation. This provides glulam with additional advantages over other, more traditional materials. As glulam products have been developed, it has become a more desirable building material. Product development has been progressive. Initially used to span greater distances than traditional timber, architects and experimented with glulam, increasing spans and creating new designs.

The glulam industry

responded creating new products that has further allowed new designs to be

74 created. Glulam has enabled more complex designs to be achieved, particularly in the timber construction industry. Over time glulam has been used within the construction industry increasingly, which resulted in further product development and increased customer satisfaction with a successful building material. Glue laminated timber in industry has overall been a success as a worthy material with strength but also a versatile edge to achieve the perceived design.

Sustainability

y the that which uture

experts , for Venn-Diagram - principals of the Brundtland Report - hundreds of variations have since been 96 produced, some very complicated.

than using hment and m from st way to and span, Glue Laminated Timber Association, Glulam Sustainability (GLTA, n.d) nce it <http://www.glulam.co.uk/sustainability.htm> [accessed 5 January 2015] Introduction materials long spans 96

78 Due to the increase in the use of glulam as a product certain questions must be asked. An important issue that requires attention is the sustainability of the product. Sustainability can be defined as “meeting the needs of the present without compromising the ability of future generations to meet their own needs.”97 according to Ken Yeang in Designing With Nature, in reference to McDonough’s The Hannover Principles. This must be considered with all three major factors in mind; environmental, social, and economical. Within architecture, sustainability should be considered as a method of “‘Design in relation to the earth’s ecological problems (which) refers to the future and is therefore both prognostic and hypothetical.”98 The designer’s concept of the environment and sustainability throughout the design process should be considered as: “…aspects of ecology that influence the design process, the design decisions, and the designed system itself.”99 The manufacturers should also consider the sustainability of the product and the production method, as both are integral to the sustainability of a given building material. Other influential factors include the usage of the material and what happens to it at its end of life.

Ken Yeang, Designing with Nature: The Ecological Basis For Architectural Design (USA: McGraw-Hill 1995), p.1 98 Ibid., p.1 99 Ibid., p.3 97

79 Within this case these points will be investigated for glulam and its sustainability during to its construction life. The focus will be on environment impact as most of the economic and social benefits will accrue for the building in which glulam is used. However, the economic and social benefits from adding value to a natural resource (timber) including job creation should be noted. Environmentally, a major benefit is that glulam is manufactured from a renewable, natural resource. It is essential that the timber is sourced from a certified forest for example through the Forest Stewardship Council (FSC) or Programme for the Endorsement of Forest Certification (PFEC). Throughout the glulam production process, consideration is also required of carbon emissions, energy use and other environmental impacts. â&#x20AC;&#x153;No other commonly used structural material requires so little energy to produceâ&#x20AC;?100 as timber. As trees grow carbon capture occurs, therefore reducing the amount of carbon dioxide in the atmosphere through the photosynthesis, which is a natural process in plant growth. This therefore obviously makes a negative impact on the carbon emissions in the first half of the production process. However within the next process stage, the timber is chosen and dried, requiring energy use.

100

Glue Laminated Timber Association, Glulam Sustainability (GLTA, n.d) <http://www.glulam.co.uk/sustainability.htm> [accessed 5 January 2015] Introduction

80 “Throughout the process thermal inputs remain relatively low, with the result that much more carbon dioxide is bound into the completed material than is emitted. This feature is reinforced by the use of wood waste and forestry byproducts for fuel.”101 From a carbon emission and energy perspectives, there are positive benefits of using timber as a sustainable material. However, glulam also requires the use of adhesives so therefore the sustainability of the glue must be questioned. The majority of the countries producing glulam products have strict regulations on what adhesives can be used and the impact of these glues are monitored. An adhesive that can be used is “Purbond® HB E (which) is a one part, moisture reactive polyurethane, adhesive used in the production of glulam beams”102 and is

“…formaldehyde free…(and) GREENGUARD certified” 103 . There are

environmental and occupational health benefits to using a formaldehyde free solution as this chemical compound releases harmful toxins into the environment and can cause serious health problems for those who are overexposed to it. This shows that as long as more sustainable and Glue Laminated Timber Association, Glulam Sustainability – Introduction Henkel, Purbond® HB E Adhesives – Driving Performance for Glulam Beam Producers and Benefit for the Environment (USA & Canada: Henkel, 2015) <http://www.henkelna.com/purbond-hb-e-formaldehyde-free-15142.htm> [accessed 6 January 2015] 103 Ibid. 101 102

81 environmentally friendly production methods and adhesives are chosen, glulam can achieve a sustainable status. To investigate the sustainability of a building material, its lifespan and end of life also need to be considered. Glulam has a general constructional life span of, according to the GLTA, “In most structural applications, the life of Glulam can be considered virtually unlimited.”104 due to its high durability, although moisture must be controlled and maintenance will be needed. Overall, glulam offers strength and durability of the material. The way in which glulam is used can also have an impact, “refurbishments and extensions are particularly easy with timber buildings, requiring little additional energy input. Consequently a long life is normal for them, with changes of use being common.”105 It tends to be more complicated structures that can have shorter lifespans, as these may require higher maintenance. If demolition is required, a glulam structure can be removed through:

104 105

Glue Laminated Timber Association, Specifiers Guide, p.10 Glue Laminated Timber Association, Glulam Sustainability – Introduction

82 “…dismantling the structure and re-using its beams and frames, cutting the material up for re-use as smaller items, or at the very least, chipping the glulam to be burnt as fuel, substituting it for fossil fuels. It contains no harmful substances to prevent such productive burning.”106 This shows the continuation of glulam’s versatility throughout its lifetime and how it can be reused and recycled, even once it is no longer fit for purpose, therefore demonstrating the sustainability of glulam. Overall, glulam is a relatively sustainable product, especially when compared to other constructional materials. Obviously glulam is not as sustainable as timber, but it’s not far off as long as the appropriate adhesives are used. Additionally, the product should be recycled or reused for an alternate purpose at the end of its structural life span to ensure to achieve its full sustainable status. In total, with all of these factors in mind it can be said that glulam is a sustainable product.

106

Glue Laminated Timber Association, Glulam Sustainability – Introduction

Conclusion

85 The use of materials within architecture is a key consideration, both conceptually and structurally. Materiality affects how the structural system is to be composed and also defines the aesthetics of the space created. Therefore, architecturally, the possible structural material choices should be known and understood. In this dissertation, the material capabilities have been discussed over the structural element, glulam. Glue-laminated timber has been used over the past century. Over this time, its capabilities as a material have improved, and increasingly popular. Glue-laminated timber has been tested and investigated by engineers and architects to create a product, which is argued to be better than traditional timber elements. As a result, glulam constructions have increased due to the opportunities glulam has enabled. Structurally, glulam has opened up many possibilities as a desirable material due to its ‘strength-to-weight ratio’, meaning lighter weight structures can be achieved, but still withstand large loads. Another component is glulam’s ability to be made to measure, as its size and rigidity can be manipulated. This is due to the ability to ‘finger joint’ laminations to the desired or required length,

86 enabling glulam elements to extend beyond the lengths of natural timber. This allows larger spans to be covered and, combining this with the materialâ&#x20AC;&#x2122;s strength, there is less of a need for intermediate supporting columns, giving the designer more freedom, and enabling longer, more open spaces to be created. The opportunities glulam provides promote its increase in use and popularity due to its structural possibilities. If timber were to be used this would not be the case, so arguably glulam is a more structurally successful. As a material, glulam is capable of creating a variety of different structures and scales. When used in small-scale constructions, shown through David Salisburyâ&#x20AC;&#x2122;s conservatory extension, glulam tends to be used only where necessary. To use glulam appropriately, its advantages over timber should be exploited. In the case presented, the glulam beams supported a load too great for natural timber beams. Glulam in small-scale structures often tends to be more simplistic post and beam architecture. This form of construction can also be translated into large-scale structures, where traditionally timber would not have been used. However, glulam has opened up the opportunity for timber use in large-scale buildings, as displayed in Shigeru Banâ&#x20AC;&#x2122;s Tamedia Office Building. Within this design, Ban uses glulam to the best of its ability, through creating 21meter long columns that support a multi-storey timber construction. This design focuses on the use of timber to such an extent that even the joint connections are

87 timber, showings what glue-laminated timber is truly capable of and in this case the structure is left exposed to celebrate this. In contrast to post and beam constructions, glulam can also be used to create other structural systems. This is shown through Foster + Partner’s Canary Wharf Crossrail Station, where a ‘node grillage’ roof structure is created using glulam. In this design, a latticed roof structure has been designed spanning over the large station. The use of glulam in design shows the material’s ability to be used for intricate designed structural systems. This construction shows how glulam’s structural qualities can be put to good use, and therefore presents new possibilities for glulam construction. Overall, each variety of glue-laminated timber structures shows the various qualities and necessities of glulam. All three case studies, make reference to and provide evidence to support the argument that glulam is often more successful than timber in construction, as the intended designs would not have been achieved if timber was used. Glulam’s success in the construction industry can also be seen not only in its range from small-scale to large-scale structure but also through its popularity in the market. Within this industry an increase in glulam production, sales, and use can be seen. This has led to a positive change in opinion on timber

88 construction, and in particular engineered timber construction. This is the result of an increase in recognition and awareness/knowledge of these structural elements; in particular glulam and what it is capable of. A direct result of the opportunities created from the advantageous structural abilities that glulam has as a construction material. Glulam is now an increasingly well-recognised building material and has re-popularised the timber construction industry by giving it a modern-edge. Due to the increase in utilisation of glulam and expanding industry, the sustainability of glulam as a material is important. Glulam is a relatively sustainable product, especially when compared to some other building materials like steel and concrete. The most sustainable element of glulam is that it is a natural renewable source. Glulam can, however, fall down in its sustainable ranking depending on the adhesive used, although environmentally sustainable solutions are available. Therefore if a sustainable adhesive is chosen, glulam can be rated as a very sustainable product, approaching natural timberâ&#x20AC;&#x2122;s ultimate sustainability. On the whole, as an engineered timber product, glulam has modernised timber construction, through maintaining a timber aesthetic but with improved structural abilities. Glulam can be utilised through traditional timber

89 construction methods. However, where glulam makes the most impressive impact is its ability to be used within contemporary designs, which require an intricate, engineered structural system.

Overall the use of glulam within

architectural design is successful through the conceptual aesthetics and structural abilities, and is often better than timber itself. Glulamâ&#x20AC;&#x2122;s popularity will continue to grow and it will continue to revive the timber construction industry.

91 BIBLIOGRAPHY

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94 HESS Timber, Production of Glulam Wood (Kleinheubach, Germany: HESS TIMBER, 2010) <http://www.hesstimber.com/en/brettschichtholz/technische_infos/herstellung/> [accessed 10 January 2015] Oxford Dictionaries, Materiality (UK: Oxford University Press, 2014) <http://www.oxforddictionaries.com/definition/english/materiality> [accessed 5 January 2015] Shigeru Ban Architects, Tamedia New Office Building (Shigeru Ban Architects, 2013) http://www.shigerubanarchitects.com/works/2013_tamediaoffice-building/index.html > [accessed 10 January 2015] Statista, U.S. Glulam Timber Production 2009-2013 (Statista, n.d) <http://www.statista.com/statistics/238006/us-glulam-timberproduction/> [accessed 10 January 2015] IMAGE REFERENCES David Salisbury, Elevation of Conservatory â&#x20AC;&#x201C; 83941-Q2 (N.Yorkshire: David Salisbury, 2014) David Salisbury, Perspective Plan Overview â&#x20AC;&#x201C; 83941-Q2(N.Yorkshire: David Salisbury, 2014) David Salisbury, Section on A-A (N. Yorkshire: David Salisbury, 2014) Didier Boy de la Tour, Tamedia Office Building / Shigeru Ban Architects (ArchDaily, 2014) <http://www.archdaily.com/478633/tamedia-office-building-shigeruban-architects/> [accessed 10 January 2015]

95 Didier Boy de la Tour, Technology: Seven Storey Wood Office Buildings in Zurich (Detail Inspiration, 2014) <http://detailonline.com/inspiration/technology-seven-storey-wood-office-buildingin-zurich-108958.html> [accessed 10 January 2015] F. Graham, Original Image of Designed Conservatory (N.Yorkshire: 2015) Foster + Partners, Projects/Canary Wharf Crossrail (London: Foster + Partners, 2015) <http://www.fosterandpartners.com/projects/canary-wharfcrossrail/>[accessed 11 January 2015] Description Fraser Wood Industries, Glulam (Canada: Fraser Wood, n.d.) <http://www.fraserwoodindustries.com/index.php?action=resources.gal lerydetail&catid=9> [accessed 12 January 2015] [used for front and back cover image] Glue Laminated Timber Association, Glulam Sustainability (GLTA, n.d) <http://www.glulam.co.uk/sustainability.htm> [accessed 5 January 2015] Introduction Shigeru Ban Architects, Tamedia Office Building / Shigeru Ban Architects (ArchDaily, 2014) <http://www.archdaily.com/478633/tamedia-office-building-shigeruban-architects/> [accessed 10 January 2015] TABLE REFERENCE Stratalam, NZ Engineered Glulam, Span Tables (New Zealand: Stratalam, n.d.)

96 <http://www.stratalam.co.nz/_resources/StratalamSpanTables.pdf> [accessed 12 January 2015] p.6