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"

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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. Chapter 3: Climate Considerations
Exterior Climate
Temperature &
Humidity
Rainfall
Interior Climate
HVAC systems
Ventilation
Architectural Form
& Enclosure
Design

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. 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. 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. 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. 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. 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. 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. Insulation Placement and Assembly Design Considerations
Interior
Insulation
Exterior
Insulation
Split
Insulation

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. 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. 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. Cladding Attachment through Exterior Insulation

31. Insulation Placement – Below Grade Walls
Interior-insulated wall
Exterior-insulated wall
Interior- and exteriorinsulated wall (ICF)

32. Insulation Placement - Roofs
Interior-insulated pitched roof
Low-slope roof: conventionally
insulated
Low-slope roof: inverted

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. 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. 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. 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. 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. 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. Cross Laminated Timber Construction - Considerations

40. Cross Laminated Timber Construction – Wall Assemblies

41. CLT Panel Construction - Unique Details for Consideration

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. 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. CLT Panel Details Requiring Attention - Corners
Airflow path more
convoluted – lower
leakage rates, but still a
consideration

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. 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. Infill Walls – Post & Beam or Concrete Floor Slabs
Concrete frame with
wood-frame infill
Post and Beam with
wood-frame infill

48. Chapter 4: Below Grade Walls
Exterior Insulated
Interior Insulated
Control
Functions
Critical
Barriers
Effective Rvalues

49. Chapter 4: Pitched-Roof, Vented Attic Assembly
Materials & Control
Functions
Critical Barriers
Effective R-value
Tables (accounting for
insulation reductions
at eaves)

50. Chapter 4: Pitched-Roof, Exterior Insulated Assembly
Materials & Control
Functions
Critical Barriers
Effective R-values

51. Chapter 4: Low-Slope Conventional Roof Assembly
Materials & Control
Functions
Critical Barriers
Effective R-values
(Accounting for
tapered insulation
packages)

52. Chapter 4: Low-Slope Inverted Roof Assembly
Materials & Control
Functions
Critical Barriers
Effective R-values

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. Detailing – Materials & Critical Barrier Discussion
Thermal Continuity
Air Barrier Continuity
Water Shedding Surface and Water Resistive Barrier

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. Detailing – Colored 2D Details

57. Detailing – Wall to Roof Interfaces

58. Detailing – Wall Penetrations

59. Detailing – 2D Window Details

60. Detailing – 3D Window Installation Sequences

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. 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. 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