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 non-
AIA, 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 wood-frame
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
Climate
Zone
and
HDD(°C)
Wood-­‐frame,
above-­‐grade
wall
Wood-­‐frame
roof,
flat
or
sloped:
[R-­‐value
(RSI)]
[R-­‐value
(RSI)]
Zone
4:
<3000
HDD
18.0
(3.17)
25.0
(4.41)
Zone
5:
3000
to
3999
HDD
20.4
(3.60)
31.0
(5.46)
Zone
6:
4000
to
4999
HDD
23.0
(4.05)
31.0
(5.46)
Zone
7a:
5000
to
5999
HDD
27.0
(4.76)
35.0
(6.17)
Zone
7b:
6000
to
6999
HDD
27.0
(4.76)
35.0
(6.17)
Zone
8:
>7000
HDD
31.0
(5.46)
40.0
(7.04)
NECB 2011
Climate
Zone
Wood-­‐frame,
above-­‐grade
wall
NECB has higher
effective R-value
requirements
Wood-­‐frame
roof—insulation
entirely
above
deck
Wood-­‐frame
roof—attic
and
other
Effective
[R-­‐value
(RSI)]
Nominal
[R-­‐value
(RSI)]
Effective
[R-­‐value
(RSI)]
Nominal
[R-­‐value
(RSI)]
Effective
[R-­‐value
(RSI)]
Nominal
[R-­‐value
(RSI)]
Zone
1
(A
&
B)
11.2
(2.0)
13.0
(2.3)
20.8
(3.7)
20.0
ci
(3.5
ci)
37.0
(6.5)
38.0
(6.7)
Zone
2
(A
&
B)
11.2
(2.0)
13.0
(2.3)
20.8
(3.7)
20.0
ci
(3.5
ci)
37.0
(6.5)
38.0
(6.7)
Zone
3
(A,
B,
&
C)
11.2
(2.0)
13.0
(2.3)
20.8
(3.7)
20.0
ci
(3.5
ci)
37.0
(6.5)
38.0
(6.7)
Zone
4
(A,
B,
&
C)
15.6
(2.7)
13.0
+
3.8
ci
(2.3
+
0.7
ci)
20.8
(3.7)
20.0
ci
(3.5
ci)
37.0
(6.5)
38.0
(6.7)
Zone
5
(A,
B,
&
C)
19.6
(3.5)
13.0
+
7.5
ci
(2.3
+
1.3
ci)
20.8
(3.7)
20.0
ci
(3.5
ci)
37.0
(6.5)
38.0
(6.7)
Zone
6
(A
&
B)
19.6
(3.5)
13.0
+
7.5
ci
(2.3
+
1.3
ci)
20.8
(3.7)
20.0
ci
(3.5
ci)
37.0
(6.5)
38.0
(6.7)
Zone
7
19.6
(3.5)
13.0
+
7.5
ci
(2.3
+
1.3
ci)
20.8
(3.7)
20.0
ci
(3.5
ci)
37.0
(6.5)
38.0
(6.7)
Zone
8
27.8
(4.9)
13.0
+
15.6
ci
(2.3
+
2.7
ci)
20.8
(3.7)
20.0
ci
(3.5
ci)
47.6
(8.4)
49.0
(8.6)
ci
=
continuous
insulation,
where
denoted
ASHRAE 90.1 - 2010

15. ASHRAE 90.1-2010 vs NECB 2011 – Effective Dec 20, 2014
Climate
Zone
Wall
–
Above
Grade:
Min.
R-­‐value
(IP)
Roof
–
Sloped
or
Flat:
Min.
R-­‐value
(IP)
Window:
Max.
U-­‐value
(IP)
8
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
18.6
25.0
0.42
NECB 2011
ASHRAE 90.1-2010 –
Residential Building
Climate
Zone
Wall
(Mass,
Wood,
Steel):
Min.
R-­‐value
(IP)
Roof
(ASc,
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
*7A/7B
combined in
ASHRAE 90.1
No Zone 4 in
ASHRAE 90.1

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
Climate
Zones
Wood-­‐frame,
above-­‐grade
wall
Wood-­‐frame
roof—insulation
entirely
above
deck:
Wood-­‐frame
roof—attic
and
other:
[R-­‐value
(RSI)]
[R-­‐value
(RSI)]
[R-­‐value
(RSI)]
Zones
1
to
3:
hot,
cooling
dominated
R-­‐16
to
R-­‐22
(2.8
to
3.9)
R-­‐25
to
R-­‐30
(4.4
to
5.3)
R-­‐40
to
R-­‐50
(7.0
to
8.8)
Zones
4
to
5:
mixed,
heating
and
cooling
R-­‐22
to
R-­‐28
(3.9
to
4.9)
R-­‐30
to
R-­‐40
(5.3
to
7.0)
R-­‐50
to
R-­‐60
(8.8
to
10.6)
Zones
6
to
8:
cold,
heating
dominated
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)

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
2x4
(or
2x6)
stud
wall
CLT/mass
timber
2x4
(or
2x6)
stud
wall
Interior-­‐insulated
wall
assemblies
Exterior-­‐insulated
wall
assemblies
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
exterior-­‐
insulated
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 heat-loss
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
Nominal
stud-­‐
space
insulation
[R-­‐value
(RSI)]
Exterior
insulation
None
[R-­‐value
(RSI)]
R-­‐4
(1
inch)
[R-­‐value
(RSI)]
R-­‐8
(2
inches)
[R-­‐value
(RSI)]
R-­‐12
(3
inches)
[R-­‐value
(RSI)]
R-­‐16
(4
inches)
[R-­‐value
(RSI)]
R-­‐20
(5
inches)
[R-­‐value
(RSI)]
R-­‐24
(6
inches)
[R-­‐value
(RSI)]
2x4
R-­‐12
(2.1)
10.7
(1.9)
15.0
(2.6)
18.8
(3.3)
22.5
(4.0)
26.2
(4.6)
29.7
(5.2)
33.2
(5.8)
R-­‐14
(2.5)
11.5
(2.0)
15.8
(2.8)
19.6
(3.4)
23.2
(4.1)
27.0
(4.8)
30.5
(5.4)
34.0
(6.0)
2x6
R-­‐19
(3.3)
15.5
(2.7)
19.8
(3.5)
23.7
(4.2)
27.3
(4.8)
31.0
(5.5)
34.5
(6.1)
38.0
(6.7)
R-­‐22
(3.9)
16.6
(2.9)
21.0
(3.7)
24.8
(4.4)
28.5
(5.0)
32.2
(5.7)
35.7
(6.3)
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
Nominal
fill
insulation
[R-­‐value/inch
(RSI/cm)]
Gap
width
between
stud
walls
No
gap
[R-­‐value
(RSI)]
1-­‐inch
[R-­‐value
(RSI)]
2-­‐inches
[R-­‐value
(RSI)]
3-­‐inches
[R-­‐value
(RSI)]
4-­‐inches
[R-­‐value
(RSI)]
5-­‐inches
[R-­‐value
(RSI)]
6-­‐inches
[R-­‐value
(RSI)]
Double-­‐
stud
2x4
R-­‐3.4/inch
(0.24/cm)
19.1
(3.4)
22.9
(4.0)
26.5
(4.7)
30.0
(5.3)
33.4
(5.9)
36.9
(6.5)
40.3
(7.1)
R-­‐4.0/inch
(0.28/cm)
20.5
(3.6)
25.1
(4.4)
29.4
(5.2)
33.4
(5.9)
37.4
(6.6)
41.5
(7.3)
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
Exterior
insulation
[R-­‐value/inch
(RSI/cm)]
Exterior
insulation
thickness
3
inches
R-­‐value
(RSI)]
4
inches
[R-­‐value
(RSI)]
5
inches
[R-­‐value
(RSI)]
6
inches
[R-­‐value
(RSI)]
7
inches
[R-­‐value
(RSI)]
8
inches
[R-­‐value
(RSI)]
3½-­‐inch-­‐
thick
CLT
panels
R-­‐4/inch
(0.28/cm)
17.2
(3.0)
20.9
(3.7)
24.4
(4.3)
27.9
(4.9)
31.6
(5.6)
35.0
(6.2)
R-­‐5/inch
(0.34/cm)
19.8
(3.5)
24.4
(4.3)
28.7
(5.1)
32.9
(5.8)
37.3
(6.6)
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
effect and pressures at parapet
corners
Roofing membrane applied,
path becomes longer – but
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
Post and Beam with
wood-frame infill
Concrete frame with
wood-frame infill

48. Chapter 4: Below Grade Walls
! Interior Insulated
! Exterior Insulated
! Control
Functions
! Critical
Barriers
! Effective R-values

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/
AdvancedBuildingSystem/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