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WoodWorks 2013 Vancouver - Energy-Efficient Building Enclosure Design Guidelines for Wood-Frame Buildings

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Presentation from the 2013 Vancouver Woodworks Conference (October 29, 2013). Covers an overview of the considerations for energy-efficient wood frame building enclosures while outlining the content of a new guideline document published by FP Innovations "Guide for Designing Energy Efficiency Building Enclosures for Wood-Frame Multi-Unit Residential Buildings in Marine to Cold Climate Zones in North America"

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WoodWorks 2013 Vancouver - Energy-Efficient Building Enclosure Design Guidelines for Wood-Frame Buildings

  1. 1. Energy-Efficient Building Enclosure Design Guidelines for Wood-Frame Buildings Graham Finch, MASc, P.Eng Principal, Building Science Research Specialist RDH Building Engineering Ltd. October 29, 2013 – Wood WORKS! Vancouver
  2. 2. Copyright Materials This presentation is protected by Canadian, US, and International Copyright laws. Reproduction, distribution, display and use of the presentation without written permission of the speaker is prohibited. © RDH Building Engineering Ltd.
  3. 3. Program Education Credit Information Canadian Wood Council, Wood WORKS! and the Wood Solutions Fair is a Registered Provider with The American Institute of Architects Continuing Education System; the Architectural Institute of British Columbia and the Engineering Institute of Canada. Credit earned on completion of this program will be reported on behalf of members of each CES provider for those who complete a participation form at the registration counter. Certificates of Completion for nonAIA, AIBC or EIC members are available on request. This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.
  4. 4. Learning Objectives 1. Learn about the new wood-design resource for architects, builders, and engineers: the Guide for Designing Energy Efficiency Building Enclosures for Wood-Frame Multi-Unit Residential Buildings 2. Understand how upcoming building and energy code changes will impact typical wood-frame construction practices, and learn the best strategies to design, insulate, air-seal, and detail new wood frame wall and roof assemblies. 3. Learn about the building enclosure design considerations for heavy timber structures utilizing CLT and post-and-beam components. 4. Understand the importance of “critical barriers” in building enclosure detailing with examples of wall, roof and window details for highly insulated wood buildings.
  5. 5. Overview Background Overview of the new Guide for Designing Energy Efficient Building Enclosures for Wood-frame Buildings Available as free download from FP Innovations
  6. 6. Evolution Wood-frame Building Enclosure Design Guides Original 1999/2011 Wood Frame Envelopes in the Coastal Climate of British Columbia - Best Practice Guide (CMHC) Emphasis on moisture control on the west coast 2011 Building Enclosure Design Guide – Wood-frame Multi-Unit Residential Buildings (HPO) Emphasis on best practices, moisture and new energy codes 2013 Guide (FP Innovations) Focus on highly insulated wood-frame assemblies to meet current and upcoming energy codes Passive design and green buildings
  7. 7. Why a New Building Enclosure Guide? Energy Codes across North America have incrementally raised the bar to the point where conventional wood-frame assemblies (i.e. 2x6 walls) no longer provide enough insulating value Increased awareness of passive design strategies and green building programs dictate even higher enclosure performance Little guidance on building durable and highly insulated enclosure assemblies and details Desire to build taller and taller more exposed woodframe buildings (4-6 stories and higher) Increased use of cross-laminated timber & other engineered wood products dictates alternate assemblies
  8. 8. What Types of Buildings & Structures is the Guide For? Multi-Unit Residential Buildings are the focus of the guide (and one of most challenging building types) Relevant for other building types as well utilizing platform framing, cross laminated timber, wood frame infill, & post and beam. Also applies to houses
  9. 9. Where is the Guide Applicable North American Guide Marine, Cold and Very Cold Climate Zones Energy Code Climate Zones 4 through 7 Details used as examples are west coast focused (i.e. rainscreen) Guidance can also be applied to other climate zones (i.e. Far-North or Southern US) with engineering judgement & local experience
  10. 10. Overview: What is in the Guide Chapter 1: Introduction Context of Guide Chapter 2: Building and Energy Codes across North America Canadian Building and Energy Codes US Building and Energy Codes Performance Rating Systems & Green Building Programs Differences between NECB & ASHRAE 90.1
  11. 11. Overview: What is in the Guide Chapter 3: Moisture, Air and Thermal Control Building as a System Climate Zones Interior Climate, HVAC Interaction Critical Barrier Concept Control of Rainwater Penetration Control of Air Flow Controlling Condensation Construction Moisture Controlling Heat Flow and Insulation Whole Building Energy Efficiency Computer Simulation Considerations for Wood-frame Enclosures
  12. 12. Overview: What is in the Guide Chapter 4: Energy Efficient Wall and Roof Assemblies Above Grade Wall Assemblies • Split Insulated, Double Stud/Deep Stud, Exterior Insulated • Infill Walls for Concrete Frame Below Grade Wall Assemblies • Interior and Exterior Insulated Roof Assemblies • Steep Slope & Low Slope Chapter 5: Detailing 2D CAD (colored) and 3D build-sequences for various typical enclosure details Chapter 6: Further Reading & References
  13. 13. Chapter 2: Building and Energy Codes Review of effective R-values & Consideration for Thermal Bridging Energy Use in Wood-frame MURBs Enclosure R-value Targets and Airtightness Requirements Canadian Building Codes • 2010 NBC • 2011 NECB • ASHRAE 90.1 (2001 through 2010 versions) US Buildings Codes Performance Rating and Green Building Programs
  14. 14. Canadian Energy Codes –NECB 2011 vs ASHRAE 90.1 NECB 2011 Climate Zone and HDD(°C) Zone 4: <3000 HDD Zone 5: 3000 to 3999 HDD Zone 6: 4000 to 4999 HDD Zone 7a: 5000 to 5999 HDD Zone 7b: 6000 to 6999 HDD Zone 8: >7000 HDD Wood-frame, above-grade wall [R-value (RSI)] 18.0 (3.17) 20.4 (3.60) 23.0 (4.05) 27.0 (4.76) 27.0 (4.76) 31.0 (5.46) Wood-frame roof, flat or sloped: [R-value (RSI)] 25.0 (4.41) 31.0 (5.46) 31.0 (5.46) 35.0 (6.17) 35.0 (6.17) 40.0 (7.04) NECB has higher effective R-value requirements ASHRAE 90.1 - 2010 Climate Zone Wood-frame, above-grade wall Effective Nominal [R-value (RSI)] [R-value (RSI)] Zone 1 11.2 13.0 (A & B) (2.0) (2.3) Zone 2 11.2 13.0 (A & B) (2.0) (2.3) Zone 3 11.2 13.0 (A, B, & C) (2.0) (2.3) Zone 4 15.6 13.0 + 3.8 ci (A, B, & C) (2.7) (2.3 + 0.7 ci) Zone 5 19.6 13.0 + 7.5 ci (A, B, & C) (3.5) (2.3 + 1.3 ci) Zone 6 19.6 13.0 + 7.5 ci (A & B) (3.5) (2.3 + 1.3 ci) Zone 7 19.6 13.0 + 7.5 ci (3.5) (2.3 + 1.3 ci) Zone 8 27.8 13.0 + 15.6 ci (4.9) (2.3 + 2.7 ci) ci = continuous insulation, where denoted Wood-frame roof—insulation entirely above deck Effective [R-value (RSI)] 20.8 (3.7) 20.8 (3.7) 20.8 (3.7) 20.8 (3.7) 20.8 (3.7) 20.8 (3.7) 20.8 (3.7) 20.8 (3.7) Nominal [R-value (RSI)] 20.0 ci (3.5 ci) 20.0 ci (3.5 ci) 20.0 ci (3.5 ci) 20.0 ci (3.5 ci) 20.0 ci (3.5 ci) 20.0 ci (3.5 ci) 20.0 ci (3.5 ci) 20.0 ci (3.5 ci) Wood-frame roof—attic and other Effective [R-value (RSI)] 37.0 (6.5) 37.0 (6.5) 37.0 (6.5) 37.0 (6.5) 37.0 (6.5) 37.0 (6.5) 37.0 (6.5) 47.6 (8.4) Nominal [R-value (RSI)] 38.0 (6.7) 38.0 (6.7) 38.0 (6.7) 38.0 (6.7) 38.0 (6.7) 38.0 (6.7) 38.0 (6.7) 49.0 (8.6)
  15. 15. ASHRAE 90.1-2010 vs NECB 2011 – Effective Dec 20, 2014 NECB 2011 Climate Zone Wall – Above Grade: Min. R-value (IP) Roof – Sloped or Flat: Min. R-value (IP) Window: Max. U-value (IP) ASHRAE 90.1-2010 – Residential Building 31.0 40.0 0.28 7A/7B 27.0 35.0 0.39 6 23.0 31.0 0.39 5 20.4 31.0 0.39 4 *7A/7B combined in ASHRAE 90.1 No Zone 4 in ASHRAE 90.1 8 18.6 25.0 0.42 Climate Zone Wall (Mass, Wood, Steel): Min. R-value (IP) Roof (Attic, Cathedral/Flat): Min. R-value (IP) Window (Alum, PVC/fiberglass): Max. U-value (IP) 8 19.2, 27.8, 27.0 47.6, 20.8 0.45, 0.35 7A/7B 14.1, 19.6, 23.8 37.0, 20.8 0.45, 0.35 6 12.5, 19.6, 15.6 37.0, 20.8 0.55, 0.35 5 12.5, 19.6, 15.6 37.0, 20.8 0.55, 0.35
  16. 16. US Energy Codes – IECC vs ASHRAE 90.1 Adoption of IECC and ASHRAE 90.1 varies by State Effective R-value tables provided Airtightness requirements covered Washington State and Seattle (<0.40 cfm/ft2 @75Pa) US Army Corps (<0.25 cfm/ft2 @75Pa)
  17. 17. Performance Rating Programs & R-value Targets Consideration for “above-code” enclosure performance & green building programs Performance rating and energy modeling considerations Target “high-performance” building enclosure R-values by climate Zone Wood-frame, above-grade wall Wood-frame roof—insulation entirely above deck: Wood-frame roof—attic and other: [R-value (RSI)] R-16 to R-22 (2.8 to 3.9) R-22 to R-28 (3.9 to 4.9) [R-value (RSI)] R-25 to R-30 (4.4 to 5.3) R-30 to R-40 (5.3 to 7.0) [R-value (RSI)] R-40 to R-50 (7.0 to 8.8) R-50 to R-60 (8.8 to 10.6) R-28 to R-40 (4.9 to 7.0) R-40 to R-50 (7.0 to 8.8) R-60 to R-80 (10.6 to 14.1) Climate Zones Zones 1 to 3: hot, cooling dominated Zones 4 to 5: mixed, heating and cooling Zones 6 to 8: cold, heating dominated
  18. 18. Chapter 3: Climate Considerations Exterior Climate Temperature & Humidity Rainfall Interior Climate HVAC systems Ventilation Architectural Form & Enclosure Design
  19. 19. Chapter 3: Building Science Fundamentals Deflection, Drainage, Drying and Durability Wetting and Drying Mechanisms Critical Barriers & Continuity Water Shedding Surface Water Resistive Barrier Air Barrier Thermal Insulation Rainwater Penetration control fundamentals
  20. 20. Chapter 3: Air Flow Control – Air Barrier Strategies Air Barrier Systems (Fundamentals, Materials, Performance, testing) Sealed Poly/Sheet Membranes Airtight drywall Sprayfoam Sealed-Sheathing Approaches • Unsupported sheet membranes • Supported sheet membranes with vertical strapping • Sandwiched membranes behind exterior insulation • Self-Adhered and liquid applied membranes Other Approaches
  21. 21. Chapter 3: Condensation Control Relative Humidity control Maintaining high interior surface temperatures Reducing thermal bridging Use of better windows Controlling air movement (air barrier systems) Controlling vapour diffusion (vapour retarders)
  22. 22. Managing Construction Moisture & Wood Shrinkage Keeping wood dry during transportation and construction and limiting built-in moisture Careful use of impermeable materials/membranes Controlling and accounting for wood-frame shrinkage Detailing for differential shrinkage
  23. 23. Chapter 3: Heat Flow Control & Insulation Control of Heat Flow Solar Control, Minimizing Conductive Losses, Minimizing Air Leakage Placement of Insulation within assemblies Wood framing factors Types of insulation, R-values and typical uses Thermal bridging and effective R-values
  24. 24. Chapter 3: Effective R-values All Energy Codes now consider effective R-values Nominal R-values = Rated R-values of insulation which do not include impacts of how they are installed For example R-20 batt insulation or R-10 foam insulation Effective R-values include impacts of insulation installation and thermal bridges For example nominal R-20 batts within steel studs becoming ~R-9 effective, or in wood studs ~R-15 effective
  25. 25. Chapter 3: Wood Framing Factor Impact Framing factors for studs @ 16” o.c = 25% Taller wood-frame structures framing factors >30-40% depending on structural destign
  26. 26. Insulation Placement and Assembly Design Considerations Interior Insulation Exterior Insulation Split Insulation
  27. 27. Getting to Higher R-values – Placement of Insulation Baseline 2x6 w/ R-22 batts = R-16 effective Exterior Insulation – R-20 to R-40+ effective • Constraints: cladding attachment, wall thickness Deep/Double Stud– R-20 to R-40+ effective • Constraints wall thickness Split Insulation– R-20 to R-40+ effective • Constraints: cladding attachment
  28. 28. Chapter 3: Insulation Placement – Above Grade Walls 2x6 stud wall Double-stud wall Interior-insulated wall assemblies 2x4 (or 2x6) stud wall CLT/mass timber Exterior-insulated wall assemblies 2x4 (or 2x6) stud wall Split-insulated wall assembly
  29. 29. Cladding Attachment through Exterior Insulation Longer cladding Fasteners directly through rigid insulation (up to 2” for light claddings) Long screws through vertical strapping and rigid insulation creates truss (8”+) – short cladding fasteners into vertical strapping Rigid shear block type connection through insulation, cladding to vertical strapping
  30. 30. Cladding Attachment through Exterior Insulation
  31. 31. Insulation Placement – Below Grade Walls Interior-insulated wall Exterior-insulated wall Interior- and exteriorinsulated wall (ICF)
  32. 32. Insulation Placement - Roofs Interior-insulated pitched roof Low-slope roof: conventionally insulated Low-slope roof: inverted
  33. 33. Chapter 3: Whole Building Energy Efficiency Whole building energy efficiency considerations Impact of Wall, Window and Roof R-values on overall heatloss and energy consumption Example calculations of whole building R-values Thermal mass impacts of Heavy timber structures Hygrothermal and Thermal simulation guidance
  34. 34. Chapter 4: Energy Efficient Walls – Split Insulated Material selection & guidance Control Functions Critical Barriers Effective R-value Tables Wood framing 2x4 2x6 Nominal studspace insulation [R-value (RSI)] R-12 (2.1) R-14 (2.5) R-19 (3.3) R-22 (3.9) Exterior insulation None [R-value (RSI)] 10.7 (1.9) 11.5 (2.0) 15.5 (2.7) 16.6 (2.9) R-4 (1 inch) [R-value (RSI)] 15.0 (2.6) 15.8 (2.8) 19.8 (3.5) 21.0 (3.7) R-8 (2 inches) [R-value (RSI)] 18.8 (3.3) 19.6 (3.4) 23.7 (4.2) 24.8 (4.4) R-12 (3 inches) [R-value (RSI)] 22.5 (4.0) 23.2 (4.1) 27.3 (4.8) 28.5 (5.0) R-16 (4 inches) [R-value (RSI)] 26.2 (4.6) 27.0 (4.8) 31.0 (5.5) 32.2 (5.7) R-20 (5 inches) [R-value (RSI)] 29.7 (5.2) 30.5 (5.4) 34.5 (6.1) 35.7 (6.3) R-24 (6 inches) [R-value (RSI)] 33.2 (5.8) 34.0 (6.0) 38.0 (6.7) 39.2 (6.9)
  35. 35. Exterior & Split Insulated Wood Assemblies Wood-frame and Heavy Timber Building Wall R-value Targets R-19.6 ASHRAE 90.1 R-18.6 to R-20.4 NECB Can only get ~R-16 effective within a 2x6 framed wall Industry shift towards split and exterior insulated wood-frame walls
  36. 36. Chapter 4: Energy Efficient Walls – Double Stud/Deep Stud Material selection & guidance Control Functions Critical Barriers Effective R-value Tables Wood framing Doublestud 2x4 Nominal fill insulation [R-value/inch (RSI/cm)] R-3.4/inch (0.24/cm) R-4.0/inch (0.28/cm) No gap [R-value (RSI)] 19.1 (3.4) 20.5 (3.6) 1-inch [R-value (RSI)] 22.9 (4.0) 25.1 (4.4) Gap width between stud walls 2-inches 3-inches 4-inches [R-value [R-value [R-value (RSI)] (RSI)] (RSI)] 26.5 30.0 33.4 (4.7) (5.3) (5.9) 29.4 33.4 37.4 (5.2) (5.9) (6.6) 5-inches [R-value (RSI)] 36.9 (6.5) 41.5 (7.3) 6-inches [R-value (RSI)] 40.3 (7.1) 45.4 (8.0)
  37. 37. Double/Deep Stud Insulated Walls Double 2x4/2x6 stud, single deep 2x10, 2x12, I-Joist etc. Common wood-frame wall assembly in many passive houses (and prefabricated highly insulated walls) Often add interior service wall – greater control over airtightness Inherently at a higher risk for damage if sheathing gets wet (rainwater, air leakage, vapor diffusion) – due to more interior insulation
  38. 38. Chapter 4: Energy Efficient Walls – Exterior Insulated Material selection & guidance Control Functions Critical Barriers Effective R-value Tables Wood framing 3½-inchthick CLT panels Exterior insulation [R-value/inch (RSI/cm)] R-4/inch (0.28/cm) R-5/inch (0.34/cm) 3 inches R-value (RSI)] 17.2 (3.0) 19.8 (3.5) 4 inches [R-value (RSI)] 20.9 (3.7) 24.4 (4.3) Exterior insulation thickness 5 inches 6 inches [R-value [R-value (RSI)] (RSI)] 24.4 27.9 (4.3) (4.9) 28.7 32.9 (5.1) (5.8) 7 inches [R-value (RSI)] 31.6 (5.6) 37.3 (6.6) 8 inches [R-value (RSI)] 35.0 (6.2) 41.5 (7.3)
  39. 39. Cross Laminated Timber Construction - Considerations
  40. 40. Cross Laminated Timber Construction – Wall Assemblies
  41. 41. CLT Panel Construction - Unique Details for Consideration
  42. 42. CLT Panel Details Requiring Attention – Panel Joints Sealants, tapes, & membranes applied on either side can't address this type of airflow path through the CLT lumber gaps
  43. 43. CLT Panel Details Requiring Attention - Parapets Airflow increased by stack Roofing membrane applied, effect and pressures at parapet path becomes longer – but corners doesn't go away – even if clamped, sealed etc.
  44. 44. CLT Panel Details Requiring Attention - Corners Airflow path more convoluted – lower leakage rates, but still a consideration
  45. 45. Guidance for CLT Assembly Air Barriers CLT panels air-tight as a material, but not as a system Recommend use of self-adhered sheet product air barrier membranes or thick liquid applied membrane on exterior of panels (exterior air-barrier approach) Use of loose-applied sheets (House-wraps) not generally recommended – more difficult to make airtight, perforating attachment, billowing, flanking airflow behind membrane
  46. 46. CLT Assembly Air Barrier Considerations Structural connections can interfere with air-barrier membrane installation/sequencing and sharp parts can damage materials (applied before or after)
  47. 47. Infill Walls – Post & Beam or Concrete Floor Slabs Concrete frame with wood-frame infill Post and Beam with wood-frame infill
  48. 48. Chapter 4: Below Grade Walls Exterior Insulated Interior Insulated Control Functions Critical Barriers Effective Rvalues
  49. 49. Chapter 4: Pitched-Roof, Vented Attic Assembly Materials & Control Functions Critical Barriers Effective R-value Tables (accounting for insulation reductions at eaves)
  50. 50. Chapter 4: Pitched-Roof, Exterior Insulated Assembly Materials & Control Functions Critical Barriers Effective R-values
  51. 51. Chapter 4: Low-Slope Conventional Roof Assembly Materials & Control Functions Critical Barriers Effective R-values (Accounting for tapered insulation packages)
  52. 52. Chapter 4: Low-Slope Inverted Roof Assembly Materials & Control Functions Critical Barriers Effective R-values
  53. 53. Chapter 5: Detailing 2D CAD details (colored) provided for typical details for each wall assembly type (split insulated, double stud, exterior insulated) plus some for infill walls 3D sequence details provided for window interfacing (split insulated, double stud, exterior insulated)
  54. 54. Detailing – Materials & Critical Barrier Discussion Thermal Continuity Air Barrier Continuity Water Shedding Surface and Water Resistive Barrier
  55. 55. Detailing – From Roof to Grade Details provided for each main wall assembly included Split insulated Double Stud CLT And roofs Sloped Low-slope
  56. 56. Detailing – Colored 2D Details
  57. 57. Detailing – Wall to Roof Interfaces
  58. 58. Detailing – Wall Penetrations
  59. 59. Detailing – 2D Window Details
  60. 60. Detailing – 3D Window Installation Sequences
  61. 61. Chapter 6: Further Reading, References & Glossary Further reading Builder & Design Guides Building Science Resources Energy Codes and Standards Other Research Organizations Design Software References Glossary of Building Enclosure, Energy Efficiency and Wood terms
  62. 62. Questions? gfinch@rdhbe.com - 604-873-1181 Guide Available from FP Innovations: http://www.fpinnovations.ca/ResearchProgram/AdvancedBuildingSy stem/designing-energy-efficient-building-enclosures.pdf Google: energy efficient building enclosure design guide
  63. 63. Questions / Comments? This concludes the: American Institute of Architects Architectural Institute of British Columbia Engineering Institute of Canada Continuing Education Systems Program Energy-Efficient Building Enclosure Design Guidelines for Wood-Frame Buildings

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