Building Enclosures of the Future - Building Tomorrow's Buildings Today

Building Enclosures for the Future –
Building Tomorrow’s Buildings Today
GRAHAM FINCH, MASC, P.ENG – RDH BUILDING ENGINEERING LTD.
BUILDEX VANCOUVER, FEBRUARY 25, 2015

Outline
à  Trends and Drivers for Improved Building
Enclosures & Whole Building Energy Efficiency
à  New BCBC & VBBL Building & Energy Code Updates
à  Effective R-values & Insulation Behaviour
à  Highly Insulated Walls – Alternate Assemblies &
New Cladding Attachment Strategies
à  Highly Insulated Low-Slope Roofs – Insulation
Strategies & New Research into Conventional Roofs

What do you See?
COLD

HOT

What do you see?

The Building Enclosure
à  The building enclosure separates
indoors from outdoors by
controlling:
à  Water penetration
à  Condensation
à  Air flow
à  Vapor diffusion (wetting & drying)
à  Heat flow
à  Light and solar radiation
à  Noise, fire, and smoke
à  While at the same time:
à  Transferring structural loads
à  Being durable and maintainable
à  Being economical & constructible
à  Looking good!

Industry Trends in Building Enclosure Designs
à  Trend towards more efficiently insulated
building enclosures due to higher energy
code targets and uptake of passive design
strategies
à  At a point where traditional wall/roof
designs are being replaced with new ones
à  Seeing many new building materials,
enclosure assemblies and construction
techniques
à  Greater attention paid to reducing thermal
bridging & use of effective R-values instead
of nominal insulation R-values
à  Optimization of cladding attachments for
both structural and thermal performance
à  More & more insulation is being used

Highly Insulated Building Enclosure Considerations
à  Highly insulated building enclosures require
more careful design and detailing to ensure
durability
à  More insulation = less heat flow to dry
out incidental moisture
à  Amount, type & placement of insulation
materials matter for air, vapour and
moisture control
à  Art of balancing material, cost, and
detailing considerations
à  Well insulated buildings require balancing
thermal performance of all components &
airtightness
à  No point super-insulating walls or roofs if
you have large thermal bridges - address
the weakest links first

Minimum Building & Energy Codes in BC
à  BC Building Code (BCBC 2012 w/2014
addenda)
à  Part 3 Buildings
›  ASHRAE 90.1-2010 Reference Energy Standard
›  NECB 2011 Reference Energy Code
›  New Part 9.36 Energy Efficiency Measures
à  Vancouver Building Bylaw (VBBL 2014)
›  ASHRAE 90.1-2010 Reference Energy Standard
›  NECB 2011 Reference Energy Code
à  Part 9 Houses
›  New Prescriptive Measures including R-22
effective insulated walls & U-0.25 windows

Sorting through the Confusion of BC Energy Codes
PART
9
RESIDENTIAL
BUILDINGS

3
STOREYS
OR
LESS
PRESCRIPTIVE

PATH
BUILDING
ENVELOPE

TRADE-‐OFF
PERFORMANCE

PATH
ENERGY
COST

BUDGET
METHOD
PRESCRIPTIVE

PATH
BCBC
2012

9.36.
VBBL
2014
9.25.
BUILDING
ENVELOPE

TRADE-‐OFF
VANCOUVER
ASHRAE
90.1-‐2010NECB
2011
ALL OTHER
PART
9
AND
PART

3
RESIDENTIAL
BUILDLINGS
BUILDING TYPE

Not to be Confused by the Climate Zones
ASHRAE 90.1-2010
Exception Vancouver
Climate Zone 5
NECB 2011 & BCBC Part 9.36
Vancouver Remains
Climate Zone 4
AHJs may also
choose/derive
their own
climate data
which may
shift city
climate zones
from BCBC or
ASHRAE

à  All BC Codes now require
consideration of Effective R-values
à  Nominal R-values are the rated
R-values of insulation materials
which do not include impacts of how
they are installed
à  For example 5.5” R-20 batt insulation
or 2” R-10 rigid foam insulation
à  Effective R-values are the actual
R-values of assemblies which
include for the impacts thermal
bridging through the insulation
à  For example nominal R-20 batts
within 2x6 steel studs 16” o.c.
becoming ~R-9 effective, or in wood
studs ~R-15
Code Shift to Effective R-values

à  Thermal Bridging occurs when a
conductive material (e.g. aluminum, steel,
concrete, wood etc.) provides a path for
heat to bypass or short-circuit the installed
insulation – reducing overall effectiveness
of the entire system
à  Heat flow finds the path of least resistance
à  A disproportionate amount of heat flow
occurs through thermal bridges even if
small in area
à  Often adding more/thicker insulation to
assemblies doesn’t help much as a result
à  Effective R-values account for the
additional heat loss due to thermal bridges
and represent actual heat flow through
enclosure assemblies and details
Understanding Thermal Bridging

à  Examples of Thermal Bridges in Buildings:
à  Wood framing or steel framing (studs, plates)
in insulated wall
à  Conductive cladding attachments through
insulation (metal girts, clips, anchors, screws
etc.)
à  Concrete slab edge (balcony, exposed slab
edge) through a wall
à  Windows & installation details through
insulated walls
à  Energy code compliance has historically
focused on assembly R-values – however
more importance is now being placed on
details and interfaces & included thermal
bridges
Understanding Thermal Bridging

New Things to Consider: Varying R-values
à  Recent industry research has re-highlighted the fact that
the R-value of insulation is not always constant (or as
published)
à  Renewed understanding of Aged R-values (Long-term
Thermal Resistance) & Temperature Dependant R-values
à  Dimensional stability of rigid insulations another issue

Varying Insulation R-value with Temperature
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
-20 -10 0 10 20 30 40 50 60
R-valueperInchofInsulation
Mean Temperature of Insulation (°C)
Long-Term R-value per Inch for Various Samples of Insulation vs. Mean Temperature
XPS
EPS
Mineral/Glass Fiber
Batt Low
Mineral/Glass Fiber
Batt High
Mineral Fiber Rigid
Board
Cellulose
1/2 pcf ocSPF
2 pcf ccSPF
Polyiso
Typical R-value as would be
Published @ 24°C/75°F
Published data adapated
from BSL - Thermal
Metric Project & Other
Recent Research by BSL
& RDH - data may not
representative of all
insulation types

Minimum Effective R-values – Part 3 Buildings
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
&
COV
18.6
25.0
0.42

NECB2011
ASHRAE90.1-2010–
ResidentialBuilding
Climate

Zone

Wall
(Mass,

Wood,
Steel):

Min.
R-‐value
(IP)

Roof
(AZc,

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
&
COV
12.5,
19.6,
15.6
37.0,
20.8
0.55,
0.35

4
11.1,
15.6,
15.6
37.0,
20.8
0.55,
0.40

*7A/7B
combined in
ASHRAE 90.1
COV in ASHRAE
Zone 5, NECB
Zone 4

Minimum Effective R-values – Part 9 Buildings
Climate

Zone

Wall
-‐
Above

Grade:

Minimum

R-‐value
(IP)

Roof
–
Flat

or
Cathedral:

Minimum
R-‐
value
(IP)

Roof
–
AZc:

Minimum
R-‐
value
(IP)

Window:

Max.
U-‐
value
(IP)

7A
17.5
28.5
59.2
0.28

6
17.5
26.5
49.2
0.28

5
17.5
26.5
49.2
0.32

4
15.8
26.5
39.2
0.32

WithoutaHRVWithaHRV
Climate

Zone

Wall
-‐
Above

Grade:

Minimum

R-‐value
(IP)

Roof
–
Flat

or
Cathedral:

Minimum
R-‐
value
(IP)

Roof
–
AZc:

Minimum
R-‐
value
(IP)

Window:

Max.
U-‐
value
(IP)

7A
16.9
28.5
49.2
0.28

6
16.9
26.5
49.2
0.28

5
16.9
26.5
39.2
0.32

4
15.8
26.5
39.2
0.32

COV

21.9
28
nominal
50
nominal
0.25

Resources to Help With New Part 9 Requirements
COV – Guide to R-22+ Effective
Walls in Wood-Frame Construction
BCBC – Illustrated Guides to New Part
9.36 Requirements (Climate Zones 4-8)

Resources to Help With New Part 3 Requirements
Guide to Design of Energy-Efficient
Building Enclosures
Building Enclosure Design Guide –
Currently Being Updated
New HPO Builder Insights –
ASHRAE/NECB – Available Soon!

From Code Minimum to Super Insulation
à  In BC, minimum effective R-value targets in
energy codes are in range of:
à  R-15 to R-30 effective for walls
à  R-25 to R-50 effective for roofs
à  R-2 to R-4 for windows
à  Green or more energy efficient building
programs (i.e. Passive House), have more
aggressive R-value targets in range of:
à  R-25 to R-50+ effective for walls
à  R-40 to R-80+ effective for roofs
à  R-5 to R-6+ for windows
à  Plus other drivers – air-tight, thermal
comfort, passive design, mould-free

Where to Add More Insulation in Walls?
Stuff It?
Wrap It?

Getting to Super Insulation Levels in Walls
Base 2x6
Framed
Wall <R-16
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+
Issues: cladding attachment, thickness
Issues: thermal bridging, thickness, durability
Issues: thickness, durability, interior details
Issues: cladding attachment, material selection

Design Considerations for Super Insulated Walls
à  Durability
à  Material & Labour Cost
à  Ease of Construction
à  Wood vs Steel vs Concrete Backup
à  Pre-fabrication vs Site-Built
à  Thickness & Floor Area
à  Air Barrier System & Detailing
à  Insulation type(s)
à  Water & Vapour control
à  Environmental aspects/materials
à  Cladding Attachment
à  Combustibility
à  and Others…

Deep Stud & Double Stud Wall Considerations
Double Stud TJI Stud
2x8 to 2x12 Deep
Stud w/ Interior
Service Wall
Double Stud w/
Interior Service
Wall
Double Stud w/ or w/o
interior service wall
Key design
considerations:
air barrier details,
vapour control,
overall thickness,
reducing
potential for
wetting

Interior Insulated Wall Considerations
2x6 w/ x-strapped 2x4s on
interior and filled with fibrous
or sprayfoam insulation
2x6 w/ interior
rigid foam insulation
2x6 wall w/ 2x4 X-framing
or rigid insulation at interior
Key design
considerations:
air & vapour
barrier selection,
interior services
details

Structurally Insulated Panels (SIPs) Considerations
SIPs Panel w/
EPS insulation
SIPs wall panel
SIPs wall panel w/
interior service wall
Key design
considerations:
detailing &
sealing of joints
& interfaces,
protection of
panels from
wetting

Exterior Insulated Wall Considerations
Fully exterior insulated 2x4
wall with rigid insulation
CLT wall panel with semi-
rigid exterior Insulation
2x4 frame wall with rigid
exterior insulation
Key design
considerations:
attachment of
cladding through
exterior
insulation, air
barrier/WRB
details

Split Insulated Wall Considerations
Semi-rigid or sprayfoam insulation
with intermittent thermally
improved cladding attachments
Larsen truss
over 2x4 wall
12” EPS over
2x4 wall
Key design
considerations:
type of exterior
insulation,
cladding
attachment
through exterior
insulation, air/
vapour barrier
placement
Split insulated 2x4 wall with rigid or
semi-rigid insulation

Cladding Attachment & Exterior Insulation
à  Exterior insulation is only as good as
the cladding attachment strategy
à  What attachment systems work best?
à  What is and how to achieve true
continuous insulation (ci)
performance?
à  What type of insulation?

Exterior Insulation & Cladding Attachment
Considerations
à  Cladding weight & gravity loads
à  Wind loads
à  Seismic loads
à  Back-up wall construction (wood, concrete, steel)
à  Attachment from clip/girt back into structure (studs, sheathing,
or slab edge)
à  Exterior insulation thickness
à  Rigid vs semi-rigid insulation
à  R-value target, tolerable thermal loss?
à  Ease of attachment of cladding – returns, corners
à  Combustibility requirements

Many Cladding Attachment Options & Counting
Vertical Z-girts Horizontal Z-girts Crossing Z-girts Galvanized/Stainless
Clip & Rail
Thermally Improved
Clip & Rail
Aluminum Clip & Rail Non-Conductive
Clip & Rail
Long Screws through
Insulation

Cladding Attachment: Continuous Wood Framing
~15-30% loss in R-value

Cladding Attachment: Vertical Steel Z-Girts
~65-75%+ loss in R-value

Cladding Attachment: Horizontal Steel Z-Girts

Cladding Attachment: Crossing Steel Z-Girts

Cladding Attachment: Clip & Rail, Steel
~30-50% loss in R-value for galvanized, 20-30% for stainless

Cladding Attachment: Clip & Rail, Steel

Cladding Attachment: Clip & Rail, Stainless Steel

Cladding Attachment: Clips w/ Diagonal Z-Girts

Cladding Attachment: Metal Panel Clips (Steel)

Cladding Attachment: Metal Panel Clips (Aluminum)

Cladding Attachment: Steel Clip & Rail

Cladding Attachment: Aluminum Clip & Rail
~15-30% loss in R-value (spacing dependant)

Cladding Attachment: Clip & Rail, Isolated Galvanized
à  Isolate the metal, improve
the performance
~10-25% loss in R-value (spacing dependant)

Cladding Attachment: Clip & Rail, Isolated Galvanized

Cladding Attachment: Clip & Rail, Non-Conductive
à  Remove the metal –
maximize the
performance
~5-25% loss in R-value (spacing & fastener type dependant)

Cladding Attachment: Clip & Rail, Non Conductive

Cladding Attachment: Improved Metal Panel

Cladding Attachment: Other Discrete Engineered
12’
10’

Cladding Attachment: Screws through Insulation
Longer cladding
Fasteners directly
through rigid
insulation (up to
2” for light
claddings)
Long screws through
vertical strapping and
rigid insulation creates
truss – short cladding
fasteners into vertical
strapping Rigid shear block type connection
through insulation, short cladding
fasteners into vertical strapping

Cladding Attachment: Screws Through Insulation

Cladding Attachment: Screws through Insulation

Really Thick Insulation = Really Long Screws
10” Exterior Insulation

In Other Areas of the World: Adhered EIFS
12” EPS insulation
boards (blocks?) R-54

Cladding Attachment: Masonry Ties & Shelf Angles
Continuous shelf angles
~50% R-value loss
Brick ties – 10-30% loss for
galvanized ties, 5-10% loss
for stainless steel
Shelf angle on stand-offs
only ~15% R-value loss

Cladding Attachment: Masonry Ties & Shelf Angles

Insulation Attachment Fasteners

Cladding Attachment Matters – Effective R-values
20
30
40
50
60
70
80
16.8 33.6 50.4
EffectiveR-ValueofWholeWallAssembly
(ft2·°F·hr/BTU)
Nominal R-Value of Exterior Insulation (ft2·°F·hr/BTU)
NO PENETRATIONS
NO PENETRATIONS
NO PENETRATIONS
4” – R-16.8 8” – R-33.6 12” – R-50.4
Continuous Vertical Z-Girt - 16" OC
Continuous Horizontal Z-Girt - 24" OC
Aluminium T-Clip - 16" x 48"
Intermittent Galvanized Z-Girt - 16" x 48"
Intermittent Galvanized Z-Girt - 16"x 24"
Isolated Galvanized Clip - 16" x 48"
20
30
40
50
60
70
1
6
.
3
3
.
5
0
.
Intermittent SS Z-Girt - 16" 48"
Intermittent SS Z-Girt - 16" x 24"
Fiberglass Clip - 16" x 48"
Galvanized Screws - 16" x 16"
20
30
40
50
60
70
1
6
.
8
3
3
.
6
5
0
.
4
Intermittent Galvanized Z-Girt - 16" x
Intermittent Galvanized Z-Girt - 16"x
SS Screws - 16" x 16"
Effective R-Value of 2x6 Wall (R-20 batt) + Exterior Insulation as Indicated

0%
20%
40%
60%
80%
16.8 33.6 50.4
PercentThermalDegredationofExteriorInsulation
Cladding Attachment R-values – It Matters!
20
30
40
50
60
70
1
6
.
3
3
.
5
0
.
20
30
40
50
60
70
1
6
.
8
3
3
.
6
5
0
.
4
Continuous Horizontal Z-Girt - 24" O
Intermittent Galvanized Z-Girt - 16" x
Intermittent Galvanized Z-Girt - 16"x
Percent Thermal Degradation of Exterior Insulation
4” – R-16.8 8” – R-33.6 12” – R-50.4

Getting to Super Insulation Levels in Low-Slope Roofs
Code Minimum
Insulated Roofs
Exterior Insulated+
(conventional or
inverted/PMR)
•  Best durability but
most expensive
•  Some challenges with
more layers of
insulation & detailing
•  Simple design
Deeper Joist/Truss –
(vented or unvented)
Least durable but least
expensive
•  Simple design
•  Standard details with
deeper structure
Split Insulated
(unvented)
•  Decent durability
•  Moderate cost
•  More complex
design
Conventional
Inverted/PMR
Vented

Considerations for Vented/Unvented Roofs
To vent or not to vent? That
is the question…

Considerations for Inverted/PMR Roofs
How to keep
insulation from
becoming
saturated below
pavers, ballast
or soil/green
roofs

Considerations for Conventional Insulated Roofs
-4” stone wool
-4” polyiso
-2-8” EPS
(R-50+)
8” of polyiso (R-44)
Unique drain connections/details
How much more insulation
can be added, what type(s)?

Conventional Roofing Research Study
à  Ongoing field monitoring study being
performed in Lower Mainland over
past 2.5 years to:
à  Quantify performance of different roof
membrane colors (reflective white,
neutral grey, & black) in combination
with different insulation strategies
(polyiso, stone wool, & hybrid)
à  Better understand impacts of
insulation movement, membrane
soiling and moisture movement within
conventional roofs

Why We Did It?
à  To resolve the great debate as
to selection of a dark vs a
light coloured roof membrane
in Lower Mainland of BC
à  To understand how
reasonably long light coloured
roofs stay white
à  To better understand
insulation movement & how it
impacts roofing durability
à  To monitor the performance
of hybrid insulation
approaches & alternate
protection boards
Confused owner?
New 5 Years Old

What We Have Been Monitoring
Stone wool - R-21.4
(2.5” + 3.25”, adhered)
Weight: 26.7 kg/m2
Heat Capacity: 22.7 kJ/K/m2
Polyiso - R-21.5
(2.0” + 1.5”, adhered)
Weight: 4.6 kg/m2
Heat Capacity: 6.8 kJ/K/m2
Hybrid - R-21.3
(2.5” Stone wool over 2.0” Polyiso, adhered)
Weight 14.3 kg/m2, Heat Capacity – 13.7 kJ/K/m2
Design target: Each Assembly the same ~R-21.5 nominal

Where We Have Been Monitoring
à  9 unique roof test areas, each 40’ x 40’ and each behaving
independently
à  Similar indoor conditions (room temperature) and building
use (warehouse storage)
Polyiso

Hybrid

Stone
wool

120’

120’

Grey
White
Black
Polyiso
Hybrid
Stonewool

How We Have Been Monitoring
à  Temperature
à  Heat Flux
à  Relative Humidity
à  Moisture Detection
à  Displacement
à  Solar Radiation
Heat Flux Relative Humidity &
Moisture Detection
Displacement
Temperature Solar Radiation

Study Findings: What is the
Impact of Membrane Colour?

32
50
68
86
104
122
140
158
176
194
0
10
20
30
40
50
60
70
80
90
May Jun Jul Aug Sept Oct Nov Dec Jan Feb Mar Apr
Temperature
[°F]
Temperature
[°C]
Monthly
Average
of
Daily
Maximum
Membrane
Temperatures
and
Maximum
Membrane

Temperature
for
Each
Month
by
Membrane
Colour
White Grey Black White
-‐
Maximum Grey
-‐
Maximum Black
-‐
Maximum
* *
*W-‐ISO-‐SW had
significant
data
loss
in
August
and
September
and
is
removed
from
the
average
for
those
months.
Colour – Impact on Surface Temperatures
à  Increased temperatures affect:
à  Membrane degradation/durability
à  Heat/Energy Flow through assembly

Study Findings: What is the
impact of the insulation strategy?

Varying R-value of Field Study Roofs
14
15
16
17
18
19
20
21
22
23
24
10 20 30 40 50 60 70 80 90 100 110 120 130 140
Effective
Assembly
R-‐value
-‐IP
Units
Outdoor
Membrane
Surface
Temperature
(Indoor,
72°F)
Effective
Roof
Insulation
R-‐value
-‐ Based
on
Roof
Membrane
Temperature
Stone
Wool
(Initial
or
Aged)
Hybrid
(Initial
Average)
Hybrid
(Aged)
Polyiso
(Initial
Average)
Polyiso
(Aged)
Based on laboratory measurements of actual insulation samples removed from site (and 4 year old aged polyiso
from prior research study)

Insulation Impact on Peak & Lagging
Membrane & Metal Deck Temperatures
RoofMembraneMetalDeck

Heat Flow – Variation with Insulation Strategy
SENSOR CODING:
SW - stone wool, ISO – polyiso, ISO-SW - hybrid
-‐25
-‐20
-‐15
-‐10
-‐5
0
5
10
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Heat
Flux
[W/m²]
Heat
Flux
Sensors

G-‐ISO
HF

G-‐ISO-‐SW
HF

G-‐SW
HF

Net Annual Impact of Insulation Strategy
0
100
200
300
400
500
600
-‐150
-‐100
-‐50
0
50
100
May Jun Jul Aug Sept Oct Nov Dec Jan Feb Mar Apr Annual
Degree
Days
[°C·∙days]
Daily
Energy
Transfer
[W·∙hr/m²
per
day]
Monthly
Average
Daily
Energy
Transfer
by
Insulation
Arrangement
ISO ISO-‐SW SW Heating
Degree
Days
(18°C)
OutwardHeat
FlowInwardHeat
Flow
Outward
HeatFlow
Inward
HeatFlow

Energy Consumption and Membrane/
Insulation Design
à  Energy modeling performed for a
commercial retail building (ASHRAE
building prototype template) to compare
roof membrane colour & insulation strategy
à  Included more realistic thermal performance of
insulation into energy models
à  Stone wool: Lower R-value/inch
Higher heat capacity and mass
à  Polyiso: Higher R-value/inch
(varies with temperature a lot)
Lower heat capacity
Lower mass
à  Hybrid: Stone wool on top moderates
temperature extremes of polyiso –
makes polyiso perform better

Most Energy Efficient Roofing Combination?
0
20
40
60
80
100
120
1
-‐
Miami 2
-‐
Houston 3
-‐
San
Francisco 4
-‐
Baltimore 5
-‐
Vancouver 6
-‐
Burlington
VT 7
-‐
Duluth 8
-‐
Fairbanks
Annual
Heating
Energy,
kWh/m2
Climate
Zone
Black
-‐
Aged
Polyiso
Black
-‐
Stonewool
Black
-‐
Aged
Hybrid
White
-‐
Aged
Polyiso
White
-‐
Stonewool
White
-‐
Aged
Hybrid
0
20
40
60
80
100
120
1
-‐
Miami 2
-‐
Houston 3
-‐
San
Francisco 4
-‐
Baltimore 5
-‐
Vancouver 6
-‐
Burlington
VT 7
-‐
Duluth 8
-‐
Fairbanks
Annual
Cooling
Energy,
kWh/m2
Climate
Zone
Black
-‐
Aged
Polyiso
Black
-‐
Stonewool
Black
-‐
Aged
Hybrid
White
-‐
Aged
Polyiso
White
-‐
Stonewool
White
-‐
Aged
Hybrid
Commercial Retail Building Heating Energy – kWh/m2/yr
Commercial Retail Building Cooling Energy – kWh/m2/yr

Most Energy Efficient Roofing Combination?
Lighter membrane, stone
wool or hybrid is better for
same design R-value
Darker membrane, stone
wool or hybrid is better
for same design R-value

Conclusions & Ongoing Research
à  Rated R-values of insulation do not tell the whole
story about actual heat flow through roofs (and
walls)
à  Surface colour (solar absorptivity, long-wave
emissivity), insulation type, thermal mass, latent
energy transfer all impact this
à  Durability & whole building energy consumption
impacts
à  Monitoring of long term movement, aged R-values,
membrane degradation, moisture movement and
more ongoing

à  rdh.com
Discussion & Questions
Graham Finch – gfinch@rdh.com – 604.802.5205

Building Enclosures of the Future - Building Tomorrow's Buildings Today

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