Guide for Designing Energy-Efficient WoodFrame Building Enclosures

Energy-Efficient Building Enclosure Design Guidelines for Wood-Frame Buildings

Graham Finch, MASc, P.Eng Principal, Building Science Research Specialist RDH Building Engineering Ltd.

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.

October 29, 2013 – Wood WORKS! Vancouver

Program Education Credit Information

Learning Objectives

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.

1. Learn about the new wood-design resource for architects, builders, and engineers: the Guide for Designing Energy Efficiency Building Enclosures

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.

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.

Evolution Wood-frame Building Enclosure Design Guides Overview Background Overview of the new Guide for

Designing Energy Efficient Building Enclosures for Wood-frame Buildings Available as free download from FP Innovations

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

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1

Guide for Designing Energy-Efficient WoodFrame Building Enclosures

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

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

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

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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, framing cross laminated timber, timber wood frame infill, infill & post and beam. beam Also applies to houses

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

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

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Guide for Designing Energy-Efficient WoodFrame Building Enclosures

Canadian Energy Codes –NECB 2011 vs ASHRAE 90.1

Chapter 2: Building and Energy Codes

NECB 2011

Review of effective R-values & Consideration for Thermal Bridging Energy Use in Wood-frame MURBs Enclosure R-value Targets and Airtightness Requirements

Climate Zone and HDD(°C) Zone 4: 7000 HDD

Canadian Building Codes

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)

Climate Zone

ASHRAE 90.1-2010 vs NECB 2011 – Effective Dec 20, 2014

NECB 2011 90.1--2010 – ASHRAE 90.1 Residential Building

*7A/7B combined in ASHRAE 90.1 No Zone 4 in ASHRAE 90.1

Roof – Sloped or Flat: Min. R-value (IP)

Window: Max. U-value (IP)

8

31.0

40.0

7A/7B

27.0

35.0

0.39

6

23.0

31.0

0.39

5

20.4

31.0

0.39

4

18.6

25.0

0.42

Climate Zone

0.28

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

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

0.45, 0.35

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

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

US Buildings Codes Performance Rating and Green Building Programs

Wall – Above Grade: Min. R-value (IP)

NECB has higher effective R-value requirements

ASHRAE 90.1 - 2010

• 2010 NBC • 2011 NECB • ASHRAE 90.1 (2001 through 2010 versions)

Climate Zone

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)

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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)

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 (