Presentation on the impact of more highly insulated and passive house wall designs and practices on the installation of windows. Presented at the 2016 Euroline technology forum.

1. 1
The Tradition and Science of Window
Installations – Where are We Headed with
More Highly Insulated Buildings?
EUROLINE TECHNOLOGY FORUM, OCTOBER 20, 2016
GRAHAM FINCH, MASC, P.ENG

2. 2
 A Brief History of Window Installation
Practices in BC
 Best Practices for Current BC Window
Installations
 Trends and Impacts of New Materials &
Higher Performance Buildings
 Integration of Windows into More Highly
Insulated Walls – Do’s and Don'ts
 Case Studies
Outline

3. 4
The Perpetual Question
+ ?

4. 5
We Have Come A Long Way in BC

5. 6
Vancouver Early 20th Century

6. 7
Early Window Installation “Best Practices”

7. 8
Pre 1930’s Architectural Graphic Standards
From Ramsey & Sleeper – Architectural Graphics Standards

8. 9
An Appreciation for Slope & Flashings
From Ramsey & Sleeper – Architectural Graphics Standards

9. 10
Then Some Things were Forgotten in the 1980s
?

10. 11
Building Enclosure Detailing Guidance Mid 1990s?

11. 12
No Joke…

12. 13
Oh and the Windows Leaked Too…

13. 14
And We Had Lots of Condensation Problems

14. 15
The Catastrophic Result…

15. 16
Early Attempts at Sub-Sill Flashings without Good
Water Shedding or Interface Details

16. 17
Continually Evolving Best Practices in BC

17. 18
Fundamentals: Following & Connecting the Critical
Barriers
 Water Shedding Surface (WSS)
 Water Resistive Barrier (WRB)
 Air barrier (AB)

18. 19
Current Best Practices in BC for Rainscreen Window
Installation

19. 20
Evolving BC Practices

20. 21
TOO MUCH Impermeable Peel and Stick

21. 22
So What is Changing in BC?
 Trend towards more efficiently insulated
building enclosures due to higher energy
code targets & uptake of passive
design strategies
 Greater attention to reducing thermal
bridging in building enclosures
 Many new building materials being
introduced and imported into local
market
 Window installation practices are
evolving to incorporate new and/or
imported window frames into more highly
insulated wall
 Ongoing need to balance thermal and
durability considerations

22. 23
Evolution of Wall Assemblies to Passive Levels
Base 2x6
Framed
Wall <R-16
(wood)
Exterior Insulation
R-20 to R-60+
Deep
Stud,
Double
Stud,
SIPS
R-20 –
R-80+
Split Insulation R-
20 to R-60+
Interior Insulation
R-20 to R-30+

23. 24
Deep Stud & Double Walls - w/ or w/o Service Wall

24. 25
Consideration for Window Installs – Deep Walls

25. 26
Exterior and Split Insulated Walls

26. 27
Consideration for Window Installs – Exterior Insulation
Lots of Options
including buck-outs
with Varying Levels
of Complexity!
Key detail – drain
outboard of the
insulation

27. 33
City of Vancouver – R-22 Wall & Window Details

28. 34
Industry Trends Impacting Walls & Windows
 Shift away from mechanically attached sheathing membranes/WRBs
like building paper & even synthetic membranes for more air-tight
and taller buildings
Building
Paper
RIP 2016

29. 35
Trend Towards Combined Exterior Air Barrier (AB)
Water Resistive Barrier (WRB) Approaches
Mechanically attached
AB/WRB
Self-adhered vapour
permeable sheet AB/WRB
Fluid applied vapour
permeable sheet AB/WRB

30. 36
Trend Towards Combined Exterior Air Barrier (AB)
Water Resistive Barrier (WRB) Approaches
Sealed sheathing AB (adhesive tapes or
sealants) with additional overlay WRB
Sealed coated
sheathing
AB/WRB
Sealed rigid foam insulation
AB/WRB (special tapes)

31. 38
Desire for More Vapour Permeable Materials?

32. 39
New Good and Some Not-So-Good Vapour Permeable
AB/WRB Membranes

33. 40
Ongoing Research – Use of Vapour Permeable Liquid
Flashings on Wood-frame Window Sills?
Can or should horizontal flashing membranes be
vapour permeable like the jambs & head?

34. 41
Assessing the Risk of Vapour Permeable Flashings on
Window Rough Opening
 Devised a test which looks at the uptake of moisture ponding on a horizontal window
sill flashing into the framing lumber & sheathing over time
 Compare results with control membranes that are known to fail or work well

35. 42
0
5
10
15
20
25
30
35
40
45
0 Days 7 Days 14 Days 21 Days 28 Days 35 Days 42 Days
MoistureContent(%)
Plywood Edge - At Center
Are Vapour Permeable Liquids Safe for Use on Wood-
frame Window Sills?
Safe MC <20%
not safe with these liquids or
permeable SAM
safe with this liquid &
impermeable SAM
maybe okay with
these liquids?
Moisture Content of Edge of Plywood at Window Sill

36. 43
Impact of the Wrong Liquid Applied Vapour Permeable
Flashing on a Wood Window Sill
Mould after 30 days due to absorption into OSB sheathing below a relatively absorptive &
permeable liquid applied window sill flashing

37. 44
Definitely Not the Right Product for This Application

38. 45
Oops! Someone Missed the Memo

39. 46
Tapes as “Flashing” on a Horizontal Window Sill?

40. 47
High Performance Buildings & Passive House
 Voluntary ultra-low energy construction standard
 Rapidly gaining interest & acceptance in North America
 Some codes targeting PH levels in next decade
 >R-38

41. 49
Some of BC’s First Passive Houses

42. 50
Passive House Window Considerations
 Every single Watt (Btu/hr) of
heat loss matters within a
Passive House
 It is a fine balance of a
building’s passive solar &
internal gains compared to
all of the conductive &
convective losses
 Heat loss through windows
and installation details
around perimeter becomes
very important and often
becomes a focal point for
improvement (especially
during construction!)

43. 51
Standard Window Installation Details Aren’t Often
Good Enough for PH Projects
Key considerations:
• Avoid metal flashings that bypass framing
or insulation
• Reduce wood framing around window
• Over-insulate the window frames where
feasible
• Air tight (and properly water managed)
Too much
insulation
displaced & too
large of metal
flashing
Too much
wood
Too much
wood

44. 52
PH Details May Look more Like This!

45. 53
PH Details May Look more Like This!

46. 54
Some Frames Are Made to Hide With Insulation

47. 55
Perimeter Heat Loss from Window Installations
aka Linear Transmittance, psi-value - 𝝋
 Window placement within the rough opening and the detailing
around the frame directly impacts the window perimeter heat loss &
installed U-value/R-value
 This factor is referred to as a linear transmittance, psi-value
 Bad psi-values 𝜑 = >0.040 W/m∙K
 Better psi-values 𝜑 = <0.020 W/m∙K
 Excellent psi-values 𝜑 = <0.010 W/m∙K
 The psi-value is multiplied by the perimeter length of the window and
energy added to the uninstalled window U-value to get an installed
window U-value (i.e. it always worsens it)
 Impact on whole house with lots of windows can be significant,
especially when trying to meet stringent PH targets
 Typically modeled/calculated for specific details with some baseline
values provided by PH window suppliers

48. 56
Certified Passive House Window Report Information
Window
U-values
Frame
U-values
Psi-values &
Installed U-
values

49. 60
Window Installation Linear Transmittance Thermal
Modeling
Window installation heat loss is the additional heat flow through the
interface/gap/framing/flashings between the wall and window

50. 62
Psi-Value Case Study: What Matters & How Much?
 Window:
 Euroline 4700 ThermoPlus inswing
tilt & turn with high performance triple
glazing (U-0.75 W/m2∙K, R-7.6 IP)
 Walls:
 Split insulated 2x6 wood frame filled with
fiberglass batt and 6” exterior mineral wool
with long screws through insulation to
support cladding
(R-40 effective)
 Windows installed at inner, middle and
exterior of wall with and without additional
insulation over the frames
 Additional data for deep stud 2x10 w/
interior 2x4 service wall (R-40) also
provided in handouts (no time today!)

51. 63
Split Insulated Wall – Standard Install, No Insulation
Over Frames
This means that the
window U-value gets
16% worse just by
installing it
Seems small but it
does matter when
talking about the
performance of
Windows

52. 64
Split Insulated Wall – Impact of Over Insulating Frames
16% loss in window
U-value for no over
insulation vs 8% with
No impact to worst
case modeled
window surface
temperature, <1°C at
jamb/head
Watch temperatures if
insulating on inside!
If over-insulatingat sill
watch drainage!

53. 65
Split Insulated Wall – Impact of Placement in R.O.
Based on window size of 1.2 x 1.5 m. Cladding not modeled for conservative estimate
Window towards
the exterior is
better thermally,
small impact on
interior surface
temperatures

54. 66
Split Insulated Wall – Impact of Placement in R.O. with
Over Insulating Frames
Based on window size of 1.2 x 1.5 m. Cladding not modeled for conservative estimate
Over insulation
drops psi-value by
about half
Placement impact
is similar, middle is
slightly better

55. 71
Window Size Matters!
0
2
4
6
8
10
0 2 4 6 8 10
R-Value(IP)
Length and Width of Frame (ft)
Thermal Performance of Euroline 4700 Frame - Center of Glass vs
Window vs Final Installed By Size of Frame
Center of Glass Window Installed
What
really
matters

56. 72
Rigid Foam Below & Supporting Window Frames?
 Thought by some PH designers or modelers
that it may be worth replacing one of the
wood sill plates (200 to 900 psi compressive
strength) with XPS insulation (30 psi
compressive strength @ 10% compression)
 Weight on setting block shims for a typical
triple glazed passive house window (several
hundred pounds) will be in the order of 100 to
200 pounds
 well over 30psi unless large distributed shims
or over more wood?
 Most shims are only a few square inches in
area – therefore foam compresses initially or
over time damaging installation, seals and
potentially window

57. 73
Possible Benefit of XPS Below Window Sill –
If Bearing Capacity Can Be Addressed
Can see why it might
be suggested but for a
2% difference I would
look for other
improvements unless
bearing issues are
addressed

58. 76
Bella Bella Passive House Case Study
 Design Build project for Vancouver
Coastal Health for a 6-plex staff housing
to replace housing that had burned down
 Target of passive house certification and
delivery in 6 months
 First modular Passive House in Canada
 First Passive House in a First Nations
Community

59. 77
The Window Details!
2x6 wood frame wall with 6”
exterior insulation

60. 78
Split Insulated Passive House Window Installation

61. 79
Split Insulated Passive House Window Installation

62. 80
Split Insulated Passive House Window Installation

63. 81
Split Insulated Passive House Window Installation

64. 82
Split Insulated Passive House Window Installation

65. 83
Modular Passive House Construction

66. 84
Modular Shipping

67. 85
Site Assembly & Completion

68. 86
Key Conclusions
 Long history of iterative progress in the
installation of windows in British
Columbia – many past failures and
successes
 Evolution is continuing with higher
performance windows (imported and
locally made in more highly insulated
wall assemblies
 Be careful with the selection of new
membranes, flashings, tapes, sealants
and foams – ensure durability and
moisture control while balancing thermal
needs
 Always look at continually improving the
thermal performance of your window
installation details!

69. 87
Discussion + Questions
CONTACT ME AT:
gfinch@rdh.com
604-873-1181