Wood-Frame Construction and Engineered Wood Products an introduction Patrice Tardif Consulting 1

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1 Wood Frame Construction and Engineered Wood Products AN INTRODUCTION Architectural Structures Arch 241 Patrice R. Tardif, B. Arch. Overview Life cycle of building materials Why wood? Introduction to wood frame construction and wood products Engineered wood products, their make-up, attributes and uses Montreal, Quebec Intuit Office, development centre, call centre Edmonton, Alberta (2002) Patrice Tardif Consulting 1

2 Blue Mountain Ski Resort Colllingwood, Ontario Dollarama Le Huard Quincaillerie Home Hardware Chibougamau, Québec (2003) Jackson Triggs Winery Niagara-on-the-Lake, Ontario (2001) xxx Poste de pompiers Alberta (2001) Patrice Tardif Consulting 2

3 Bibliothèque de Val Cartier Val Cartier (2002) Gene H. Kruger Pavilion, Laval University Sainte-Foy (2005) Patrice Tardif Consulting 3

4 Limoges Concert Hall Limoges, France (2006) Albert Mianscum Memorial Sports Complex Oujé-Bougoumou (2002) Complexe multi-sports de Laval Laval (2005) xxx Mountain Equipment Co-op Montréal, Québec (2003) Magasin d articles de sport Gerrick s Cranbrook, Colombie-Brittanique (2005) Patrice Tardif Consulting 4

5 Club de golf Saint-Prime-sur-le-lac Saint-Prime, Québec (2003) Parc des Hautes, Sépaq Charlevoix, Québec Patrice Tardif Consulting 5

6 Gare Intermodale de Saint-Jérôme Saint-Jérôme (2004) Brentwood Skytrain Station Burnaby, B.C. (2001) Thunder Bay Hospital Thunder Bay, Ontario (2002) Credit Valley Hospital Mississauga, Ontario (2004) Patrice Tardif Consulting 6

7 Life Cycle of Building Materials Cathedral of Christ the Light Oakland, California (2008) An introduction to life cycle analysis (LCA) building materials from cradle to grave LCA evaluation of building materials resource extraction manufacturing requirements on-site construction occupancy / maintenance demolition recycling / reuse / disposal Certification programs examples LEED An introduction to Life Cycle Analysis An introduction to Life Cycle Analysis cont LIFE CYCLE ANALYSIS (LCA) LCA is a tool that can be used to assess the burdens placed on the environment by a product through all stages of its life. Two main aspects to LCA: Data acquisition Data analysis Cradle to Grave Patrice Tardif Consulting 7

8 LCA evaluation of building materials Cradle to Grave resource extraction manufacturing requirements on-site construction occupancy / maintenance demolition recycling / reuse / disposal Biomass Facility Recycling CO 2 Sawmill Panel Manufacturing CO 2 Extraction LCA evaluation of building materials resource extraction LCA evaluation of building materials cont LCA evaluation of building materials cont manufacturing requirements resource extraction cont Patrice Tardif Consulting 8

9 LCA evaluation of building materials cont LCA evaluation of building materials cont on-site construction cont on-site construction LCA evaluation of building materials cont LCA evaluation of building materials cont occupancy / maintenance demolition Patrice Tardif Consulting 9

10 LCA evaluation of building materials cont recycling / reuse / disposal LCA evaluation of building materials cont Life cycle assessments look at environmental impacts, such as: acid rain air pollution health smog indoor air quality water intake global warming habitat alteration ecological toxicity ozone depletion fossil fuel depletion According to LCA, wood products are the most environmentally responsible construction materials when taking into consideration all of these factors. LCA evaluation of building materials cont Two main aspects to LCA: Data acquisition Data analysis Interpretation Value judgements Certification programs product standards (ANSI, CGSB, ISO) certified forest management practices CSA FSC SFI environmentally preferable products Green Seal Green Cross EPP performance measurement tools BREEAM (Green Leaf) Green Globes LEED GB Tool Patrice Tardif Consulting 10

11 Why wood? Renewable and sustainable Durable Environmentally responsible (manufacturing) Reduces global greenhouse gas emissions Thermally efficient Subjective properties Why wood? renewable and sustainable Over 600 million seedlings are planted in Canada each year Renewable and sustainable Renewable and sustainable cont CANADA Sweden Russian Federation Indonesia United States New Zealand China United Kingdom 6% 40% 29% 26% 21% 16% 68% 66% 64% 63% 60% 91% 90% 86% 82% 0% 20% 40% 60% 80% 100% The rate of growth in Canada s commercial forests is equivalent to: - 50,354 houses a day - 2,098 houses an hour - 35 houses a minute Source : FAO State of the World`s Forests 2005 Patrice Tardif Consulting 11

12 Renewable and sustainable cont Renewable and sustainable cont Sustainable Forest Management certification (SFM) in Canada, (millions of ha) CSA SFI FSC End of year 78.0 CSA 36.1 SFI 24.4 FSC Source: Canadian Sustainable Forestry Certification Coalition December CANADA États-Unis 42.2 Finlande 22.5 Suède Fédération Russe SFM certification in Canada and internationally, December 2007 (millions of ha) Australie Allemange Brésil Malaysie France Chile 1.9 Mexique Source: Canadian Sustainable Forestry Certification Coalition December Durable Banc de pêche de Pasbébiac Entrepot le Boutillier built in ~ 1840 Norway : Borgund stave church 12 th century Japan : Todaiji built in 752 the largest wood building in the world most recent section built in 1692 Patrice Tardif Consulting 12

13 Why wood? cont Environmentally responsible renewable and sustainable durable environmentally responsible (manufacturing) Uses less energy to manufacture renewable and sustainable durable environmentally responsible (manufacturing) Uses less energy to manufacture Contributes less to air pollution AIR Energy Use (GJ x 10 8 ) Wood Steel Concrete Equivalent CO 2 (Tonnes) Wood Steel Concrete Environmentally responsible cont Environmentally responsible cont renewable and sustainable durable environmentally responsible (manufacturing) Uses less energy to manufacture Contributes less to water pollution WATER 165 renewable and sustainable durable environmentally responsible (manufacturing) Uses less energy to manufacture Contributes less to air and water pollution Resource extraction requirements less onerous Index Value x Wood Steel Concrete Index Value x 10 5 Wood Steel Concrete Patrice Tardif Consulting 13

14 Environmentally responsible cont renewable and sustainable durable environmentally responsible (manufacturing) Uses less energy to manufacture Contributes less to air and water pollution Resource extraction requirements less onerous Efficient use of raw resource 52 % dimension lumber & other wood products ; 30 % chips for pulp and paper ; 10 % bark for energy & mulch ; 8 % shavings for particleboard, MDF, energy and mulch. Why wood? cont renewable and sustainable durable environmentally responsible (manufacturing) reduces global greenhouse gas emissions A typical 216 sq. m. (2,400 sq. ft) wood-frame house holds 28.5 tonnes of carbon dioxide, an amount equal to the emissions of a small car over seven years. Why wood? cont renewable and sustainable durable environmentally responsible (manufacturing) reduces global greenhouse gas emissions thermally efficient R value for wood = 1.5/in. R value for steel =.0024/in. R value for concrete =.08/ in. Thermally efficient renewable and sustainable durable environmentally responsible (manufacturing) reduces global greenhouse gas emissions thermally efficient cont Wood 2x4 Steel 2x4 2 Concrete Block 6" 1 0 Assembly R Values Patrice Tardif Consulting 14

15 Why wood? cont renewable and sustainable durable environmentally responsible (manufacturing) reduces global greenhouse gas emissions thermally efficient subjective properties warmth aesthetics Why wood? cont LCA examines the entire life cycle of a product, a process or an activity... Why wood? cont Wood frame Construction Embodied and Operating Energy Steel Concrete Energy Use 12% 20% Greenhouse 15% 29% Air Pollution 10% 12% Water Pollution 300% 225% Resource Use 7% 50% Solid Waste 6% 16% For a typical building with a life expectancy of 20 years. Patrice Tardif Consulting 15

16 Wood frame Construction Wood frame Construction cont Vertical load path: live dead snow wind seismic Wood-Frame Construction Techniques: Post and Beam construction Light-frame construction Prefabricated or Manufactured construction Lateral load path: Wood frame construction cont Light-frame Construction Main Structural Elements: Columns Beams Joists Secondary Structural Elements: Sheathing Decking Closely spaced members, combined with sheathing or decking, form the structural elements of the building elements used are dimension lumber sized (2 x 4 s, 2 x 6 s, etc.) 2 basic framing methods Balloon framing Platform framing Patrice Tardif Consulting 16

17 Architectural Structures Arch Nov Wood frame construction Balloon framing cont The wall studs are continuous for the building s height Insulation Exterior finish Flooring Gypsum wallboard Sheathing Balloon framing cont The wall studs are continuous for the building s height Floor supports are let into the wall framing members Patrice Tardif Consulting Platform framing Floor assembly built separately from walls and extends to outer edge of walls 17

18 Platform framing cont Post and Beam Construction Floor assembly built separately from walls and extends to outer edge of walls Provides working surface for subsequent levels Widely-spaced sawn timbers provide structural support diagonal bracing or other support is required to resist lateral loads. Post and Beam Construction cont Prefabricated or Manufactured Construction Widely-spaced sawn timbers provide structural support diagonal bracing or other support is required to resist lateral loads Elements or systems are constructed off-site in controlled environments. diagonal bracing or other support is required to resist lateral loads large members connected using high capacity type connections, etc. Patrice Tardif Consulting 18

19 Prefabricated or Manufactured Construction cont Elements can be used in conjunction with more conventional construction techniques, or entire houses can be manufactured off-site, then transported and assembled on-site. Prefabricated or Manufactured Construction cont Advantages: controlled environment, easier to assure quality of materials and construction techniques integrated design approach quality of the building envelope speed of assembly Wood frame construction cont Products used for Main Stuctural Elements Main Structural Elements: Columns Beams Joists Dimension lumber Specialty lumber Timber Engineered wood products Patrice Tardif Consulting 19

20 Main Stuctural Elements cont Main Stuctural Elements cont Dimension lumber - 4 thick (100 mm) (nominal) - visually graded and stamped as meeting standardized grading rules (NGRDL and NLGA) - Approved by the Canadian lumber standards accreditation board Dimension lumber Specialty lumber - Machine stress-rated (MSR) visually graded and mechanically tested Main Stuctural Elements cont Main Stuctural Elements cont Dimension lumber Specialty lumber - Machine stress-rated (MSR) visually graded and mechanically tested - Finger-joined lumber machined profiles end-glued Dimension lumber Specialty lumber Timber - minimum thickness of 6 (152 mm) - visually graded and stamped as meeting NGRDL and NLGA standardized grading rules - Canadian grades and species meet CNBC requirements and CSA O86 Patrice Tardif Consulting 20

21 Main Stuctural Elements cont Wood frame construction cont Dimension lumber Specialty lumber Timber Engineered wood products - Structural composite lumber (SCL) - Wood I-joists - Light-frame trusses - Glulams Secondary Structural Elements: Sheathing Decking Products used for Secondary Stuctural Elements Secondary Stuctural Elements cont Sheathing Decking Sheathing - Plywood - Oriented strand board (OSB) Patrice Tardif Consulting 21

22 Secondary Stuctural Elements cont Engineered Wood Products Sheathing Decking or planking - Dimension lumber with tongue and grooved profile - 3 thicknesses ranging from 1.5 ( 38 mm) to 3.5 (89 mm) An Engineered Wood Product (EWP) is a product that has gone through a process to provide better or more predictable properties. more design flexibility longer spans greater load carrying capacity can use the entire tree, no matter what the species, the shape or the size a good use of raw resource with less construction waste Engineered Wood Products cont Plywood Typical engineered wood products in wood-frame construction: SCL trusses glulams plywood wood I-joists OSB Structural panel made from thin softwood veneers (plies) in alternating cross-oriented layers that are glued together under heat and pressure using waterproof adhesives. odd # of plies that are symmetrical about the centreline sanded or unsanded tongue & grooved or square-edged must be certified to product standards and stamped as such to be accepted by building codes Patrice Tardif Consulting 22

23 Plywood cont Oriented Strand Board (OSB) Plywood Attributes can be treated for added properties (resistance to fire, insects, decay) certified for exterior applications Plywood Uses floor, roof, and wall sheathing, floor underlayment, concrete formwork, box beams stressed-skin panels preserved wood foundations Structural panel made from successive layers of strands that are bonded together under heat and pressure with either waterproof adhesives or equivalent binders and wax. strands oriented in long direction of the panel in outer layers and typically cross-oriented in the core tongue& grooved or square-edged must be certified to product standards and stamped to be accepted by building codes Oriented Strand Board (OSB) cont Structural Composite Lumber (SCL) OSB Attributes added strength and stiffness in the length of the panel high shear value available in many different sizes and lengths not recommended for exposed exterior applications OSB Uses floor, roof and wall sheathing structural insulated panels wood I-joist webs concrete formwork siding Proprietary engineered wood products, each with its own design values: Parallel Strand Lumber (PSL) Laminated Veneer Lumber (LVL) Laminated Strand Lumber (LSL) Patrice Tardif Consulting 23

24 Structural Composite Lumber (SCL) cont Parallel Strand Lumber (PSL) glued products using exterior, waterproof resins similar structural capabilities need individual certification to be accepted in building codes manufacturers supply load tables and installation recommendations, as well as assist with layout drawings and sizing of members need engineer s approval or stamp PSL is an SCL that consists of strands of veneers glued together under pressure with the strands oriented along the length of the piece. beams typically available in 1-3/4 ( 44.5 mm) to 7 (178 mm) thicknesses and can be sawn to any dimension manufacturers supply load tables and installation recommendations, as well as assist with layout drawings and sizing of members ultimately need engineer s stamp Parallel Strand Lumber (PSL) cont Laminated Veneer Lumber (LVL) PSL Attributes consistent properties resistant to seasonal stresses high load-carrying capacities suited to uses where appearance is important PSL Uses beams, columns (post & beam) beams, headers lintels (light-frame) heavy timber construction in trusses LVL is an SCL that is manufactured by curing an assembly of glued veneers together in a heated press to form billets that are subsequently cut to the depths required. grain of veneers oriented parallel to the length of the piece wider members may be built-up available up to 80 (24 m) in length Patrice Tardif Consulting 24

25 Laminated Veneer Lumber (LVL) cont Laminated Strand Lumber (LSL) LVL Attributes strong when edge loaded strong when face loaded dimensional stability high strength & reliability, low variability LSL is an SCL that is manufactured from long strands of wood, oriented parallel to each other and glued. Strands are of uniform dimension and LSL is manufactured to a consistent moisture content. LVL Uses flanges for wood I-joists scaffold planking stock headers and beams columns, wall studs, in trusses Laminated Strand Lumber (LSL) cont Glued-Laminated Timber (Glulams) LSL Attributes uniform and consistent properties transfer lateral and vertical bearing forces (rimboards) dimensionally stable LSL Uses rimboard an integral component of engineered wood systems that support wall loads and tie floor joists together studs ( m) Glulams are manufactured by gluing together dimension lumber laminations with waterproof adhesives. The lumber is first visually and mechanically graded, then sorted for strength and stiffness into lamstock grades. MC range for lamstock before assembly: 7-15% lamstock is end-joined or butted then arranged in horizontal layers and glued under pressure available in stress and appearance grades available balanced & unbalanced Patrice Tardif Consulting 25

26 Glued-Laminated Timber (Glulams) cont Glued-Laminated Timber (Glulams) cont Stress grade defines strength of the material. Higher quality lamstock is located in high stress areas. Unbalanced beam: used for simple spans. Balanced beam: used for continuous spanning or cantilever applications. Appearance grade defines the amount of patching and finished work done to the exposed surfaces after laminating (industrial, commercial, quality). Glulams Attributes large members, many shapes and sizes can be curved, tapered and cambered suitable for interior or exterior use lower MC of lamstock leads to less shrinkage and checking in service Glulams Uses columns, beams, headers, girders used when structure left exposed heavy trusses Wood I-joists Wood I-joists cont Prefabricated wood I-joists are made by using exteriorrated waterproof adhesives to glue pre-dried solid sawn lumber, MSR or LVL flanges to a plywood or OSB panel web. each manufacture produces product with unique strength and stiffness characteristics using different combinations of flange and web materials with different connection details manufacturers supply allowable load and span tables need individual certification to be accepted in building codes suppliers stock standard joist hangers and other connection hardware Wood I-joist Attributes dimensionally stable, lightweight with uniform stiffness and strength and known engineering properties high strength to weight ration can be manually installed can be cut and worked using common wood working tools wide flanges allow for good fastening surface for sheathing factory pre-punched knock-out holes in web facilitate installation of electrical services Patrice Tardif Consulting 26

27 Wood I-joists cont Trusses Wood I-joist Uses well suited for longer span floor and roof joist applications economical alternative to open-web steel joists Trusses use a triangular arrangement of webs and chords to transfer loads to reaction points. 2 Truss categories light-frame trusses typically prefabricated by connecting 2 (50 mm) (nominal) dimension lumber together with metal truss plates heavy-timber trusses heavy timber or EWP (glulams, PSL) connected with specialty metal connectors Light-frame Trusses Light-frame Trusses cont made from dimension lumber of various sizes chords and webs connected using toothed galvanized steel connector plates hydraulically pressed into precut lumber at joints plates must conform to specific standard requirements Light-frame trusses - Attributes unlimited size and shape options may be manufactured to suit any roof style truss plate manufacturer typically engineers trusses on behalf of truss fabricator each proprietary product requires individual certification Patrice Tardif Consulting 27

28 Light-frame Trusses cont Light-frame Trusses cont Light-frame trusses Attributes cont all trusses are custom designed economical (ease of fabrication, simplified erection procedures) Light-frame trusses Uses residential and commercial applications flexibility in layout long spanning capabilities Open-web Joists Open-web Joists cont Open-web joists are either metal plate connected, glued or metal-webbed trusses parallel chord trusses. generally custom designed proprietary properties and installation requirements specific loadings and other structural requirements to be clearly identified for proper design of each system Open-web joists Attributes often more economical than open-web steel joists electrical, plumbing, heating and air conditioning services may be placed between the truss chords (must be specified) can be supported on the top or bottom chord can have built-in camber permits large bay sizes with no intermediate support Open-web joists Uses floor or roof joists Patrice Tardif Consulting 28

29 Engineered Wood Products cont EWP s play an important role in wood-frame construction, both on-site and in prefabricated or manufactured systems. great design flexibility easy to handle, lead to fewer cut-offs on site more efficient use of our forest reserves lack of defects and controlled MC of individual elements afford dimensional stability and high strength high weight to strength ratio economical, durable, lightweight alternative to solid sawn lumber Designing with Wood The basics choose materials that are suitable for the intended application structural elements and systems used must meet the loading requirements interior or exterior use? determine spans and optimum member profiles consider material costs, including transportation to the site form and intended function of a building may dictate certain building materials Designing with Wood cont Material is selected specify certified products that adhere to 3 rd party certification program verify local building code requirements insure product availability and support from manufacturer use appropriate connection detailing use appropriate building envelope detailing insure adequate site supervision Patrice Tardif Consulting 29

30 (also) Summary Appropriateness of wood as a construction material Life cycle analysis of building materials Wood-frame construction primary and secondary elements different framing options Introduction to EWPs, their uses and attributes General design considerations when designing with wood Acknowledgements Canadian Wood Council APA the Engineered Wood Association Faherty and Williamson ATHENA Institute Wood WORKS! Sustainable Forestry Initiative www Patrice Tardif Consulting 30