Building Enclosures For the Future - Building Tomorrows 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

Trends and Drivers for Improved Building Enclosures &

Whole Building Energy Efficiency

New BCBC & VBBL Building & Energy Code Updates

Effective R-values & Insulation Behaviour

Highly Insulated Walls – Alternate Assemblies & New

Cladding Attachment Strategies

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

The building enclosure separates

indoors from outdoors by controlling:

Water penetration

Condensation

Air flow

Vapor diffusion (wetting & drying)

Heat flow

Light and solar radiation

Noise, fire, and smoke

While at the same time:

Transferring structural loads

Being durable and maintainable

Being economical & constructible

Looking good!

Industry Trends in Building Enclosure Designs

Trend towards more efficiently insulated

building enclosures due to higher energy code

targets and uptake of passive design strategies

At a point where traditional wall/roof designs are

being replaced with new ones

Seeing many new building materials, enclosure

assemblies and construction techniques

Greater attention paid to reducing thermal

bridging & use of effective R-values instead of

nominal insulation R-values

Optimization of cladding attachments for both

structural and thermal performance

More & more insulation is being used

Highly Insulated Building Enclosure Considerations

Highly insulated building enclosures require more

careful design and detailing to ensure durability

More insulation = less heat flow to dry out

incidental moisture

Amount, type & placement of insulation

materials matter for air, vapour and moisture

control

Art of balancing material, cost, and detailing

considerations

Well insulated buildings require balancing thermal

performance of all components & airtightness

No point super-insulating walls or roofs if you

have large thermal bridges - address the

weakest links first

Minimum Building & Energy Codes in BC

BC Building Code (BCBC 2012 w/2014 addenda)

Part 3 Buildings

› ASHRAE 90.1-2010 Reference Energy Standard

› NECB 2011 Reference Energy Code

Part 9 Buildings

› New Part 9.36 Energy Efficiency Measures

Vancouver Building Bylaw (VBBL 2014)

Part 3 Buildings

› ASHRAE 90.1-2010 Reference Energy Standard

› NECB 2011 Reference Energy Code

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 20149.25.

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

All BC Codes now require consideration

of Effective R-values

Nominal R-values are the rated

R-values of insulation materials which

do not include impacts of how they are

installed

For example 5.5” R-20 batt insulation or

2” R-10 rigid foam insulation

Effective R-values are the actual

R-values of assemblies which include

for the impacts thermal bridging through

the insulation

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

http://www.google.ca/url?sa=i&rct=j&q=R-22+fiberglass+insulation&source=images&cd=&cad=rja&docid=ZXkG-DrJKsdyjM&tbnid=7Ut83MIf7LG-OM:&ved=0CAUQjRw&url=http://www.rona.ca/en/r20-fiberglass-insulation-pack&ei=rWFjUZCcFKXxigKDhoGADQ&bvm=bv.44990110,d.cGE&psig=AFQjCNG4BQZJGI6oVbv13ocInTSKxkqE4A&ust=1365553959864653

http://www.google.ca/url?sa=i&rct=j&q=R-22+fiberglass+insulation&source=images&cd=&cad=rja&docid=ZXkG-DrJKsdyjM&tbnid=7Ut83MIf7LG-OM:&ved=0CAUQjRw&url=http://www.rona.ca/en/r20-fiberglass-insulation-pack&ei=rWFjUZCcFKXxigKDhoGADQ&bvm=bv.44990110,d.cGE&psig=AFQjCNG4BQZJGI6oVbv13ocInTSKxkqE4A&ust=1365553959864653

http://www.homedepot.ca/webapp/wcs/stores/servlet/ProductImagesView?D=995375&catalogId=10051&langId=-15&storeId=10051

http://www.homedepot.ca/webapp/wcs/stores/servlet/ProductImagesView?D=995375&catalogId=10051&langId=-15&storeId=10051

http://www.google.ca/url?sa=i&rct=j&q=fiberglass+insulation+studs&source=images&cd=&cad=rja&docid=aE3GrHzZIMjz8M&tbnid=6EXM-SNXiuiMAM:&ved=0CAUQjRw&url=http://www.basementsystems.ca/basement/insulation/insulated-basement-wall.html&ei=rtFkUcnIGLGvigLDmIGwCA&bvm=bv.44990110,d.cGE&psig=AFQjCNEgMaymbU03S1v-ixqyyvm9KDtkiw&ust=1365648154374040

http://www.google.ca/url?sa=i&rct=j&q=fiberglass+insulation+studs&source=images&cd=&cad=rja&docid=aE3GrHzZIMjz8M&tbnid=6EXM-SNXiuiMAM:&ved=0CAUQjRw&url=http://www.basementsystems.ca/basement/insulation/insulated-basement-wall.html&ei=rtFkUcnIGLGvigLDmIGwCA&bvm=bv.44990110,d.cGE&psig=AFQjCNEgMaymbU03S1v-ixqyyvm9KDtkiw&ust=1365648154374040

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

Heat flow finds the path of least resistance

A disproportionate amount of heat flow occurs

through thermal bridges even if small in area

Often adding more/thicker insulation to

assemblies doesn’t help much as a result

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

Examples of Thermal Bridges in Buildings:

Wood framing or steel framing (studs, plates) in

insulated wall

Conductive cladding attachments through

insulation (metal girts, clips, anchors, screws etc.)

Concrete slab edge (balcony, exposed slab edge)

through a wall

Windows & installation details through insulated

walls

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

Recent industry research has re-highlighted the fact that the

R-value of insulation is not always constant (or as published)

Renewed understanding of Aged R-values (Long-term Thermal

Resistance) & Temperature Dependant R-values

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-v

alu

e p

er

Inch

of

Insu

lati

on

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

f r om BSL - Ther mal

Metr ic Pr oject & Other

Recent Resear ch by BSL

& RDH - data may not

r epr esentat ive of all

insulat ion types

Minimum Effective R-values – Part 3 Buildings

ClimateZone

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

NE

CB

2011

AS

HR

AE

90.1

-2010 –

Res

iden

tial B

uil

din

g ClimateZone

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 & 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

ClimateZone

Wall - Above Grade: Minimum R-value (IP)

Roof – Flat or Cathedral: Minimum R-value (IP)

Roof – Attic: Minimum R-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

Wit

ho

ut

a H

RV

Wit

h a

HR

V

ClimateZone

Wall - Above Grade: Minimum R-value (IP)

Roof – Flat or Cathedral: Minimum R-value (IP)

Roof – Attic: Minimum R-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

In BC, minimum effective R-value targets in

energy codes are in range of:

R-15 to R-30 effective for walls

R-25 to R-50 effective for roofs

R-2 to R-4 for windows

Green or more energy efficient building

programs (i.e. Passive House), have more

aggressive R-value targets in range of:

R-25 to R-50+ effective for walls

R-40 to R-80+ effective for roofs

R-5 to R-6+ for windows

Plus other drivers – air-tight, thermal comfort,

passive design, mould-free

Super Insulated Walls

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 detailsIssues: cladding attachment, material selection

Design Considerations for Super Insulated Walls

Durability

Material & Labour Cost

Ease of Construction

Wood vs Steel vs Concrete Backup

Pre-fabrication vs Site-Built

Thickness & Floor Area

Air Barrier System & Detailing

Insulation type(s)

Water & Vapour control

Environmental aspects/materials

Cladding Attachment

Combustibility

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

WallDouble 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

Exterior insulation is only as good as the

cladding attachment strategy

What attachment systems work best?

What is and how to achieve true

continuous insulation (ci) performance?

What type of insulation?

Exterior Insulation & Cladding Attachment Considerations

Cladding weight & gravity loads

Wind loads

Seismic loads

Back-up wall construction (wood, concrete, steel)

Attachment from clip/girt back into structure (studs, sheathing, or slab

edge)

Exterior insulation thickness

Rigid vs semi-rigid insulation

R-value target, tolerable thermal loss?

Ease of attachment of cladding – returns, corners

Combustibility requirements

Many Cladding Attachment Options & Counting

Vertical Z-girts Horizontal Z-girts Crossing Z-girts Galvanized/Stainless

Clip & Rail

Thermally Improved

Clip & RailAluminum 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: 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: Steel Clip & Rail

Cladding Attachment: Aluminum Clip & Rail

~15-30% loss in R-value (spacing dependant)

Cladding Attachment: Clip & Rail, Isolated Galvanized

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

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 steelShelf 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

Effective R

-Valu

e o

f W

hole

Wall

Assem

bly

(f

t2·

F·h

r/B

TU

)

Nominal R-Value of Exterior Insulation (ft2· F·hr/BTU)

NO PENETRATIONS

NO PENETRATIONS

NO PENETRATIONS

Nominal R-Value of Exterior Insulation (ft2·°F·hr/BTU)

4” – R-16.8 8” – R-33.6 12” – R-50.4

20

30

40

50

60

70

16.8

33.6

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"


Intermittent SS Z-Girt - 16" 48"

Intermittent SS Z-Girt - 16" x 24"

Fiberglass Clip - 16" x 48"


Galvanized Screws - 16" x 16"


SS Screws - 16" x 16"


20

30

40

50

60

70

16.8

33.6

50.4

















20

30

40

50

60

70

16.8

33.6

50.4

















Effective R-Value of 2x6 Wall (R-20 batt) + Exterior Insulation as Indicated

0%

20%

40%

60%

80%

16.8 33.6 50.4

Perc

ent T

herm

al D

egre

da

tion

of E

xte

rior

Insula

tio

n

Nominal R-Value of Exterior Insulation (ft2· F·hr/BTU)

Cladding Attachment R-values – It Matters!

20

30

40

50

60

70

16.8

33.6

50.4

















20

30

40

50

60

70

16.8

33.6

50.4

















20

30

40

50

60

70

16.8

33.6

50.4

















Percent Thermal Degradation of Exterior Insulation

Nominal R-Value of Exterior Insulation (ft2·°F·hr/BTU)

4” – R-16.8 8” – R-33.6 12” – R-50.4

Super Insulated Roofs

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

Ongoing field monitoring study being

performed in Lower Mainland over past

2.5 years to:

Quantify performance of different roof

membrane colors (reflective white, neutral

grey, & black) in combination with different

insulation strategies (polyiso, stone wool,

& hybrid)

Better understand impacts of insulation

movement, membrane soiling and

moisture movement within conventional

roofs

Why We Did It?

To resolve the great debate as to

selection of a dark vs a light

coloured roof membrane in

Lower Mainland of BC

To understand how reasonably

long light coloured roofs stay

white

To better understand insulation

movement & how it impacts

roofing durability

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

9 unique roof test areas, each 40’ x 40’ and each behaving

independently

Similar indoor conditions (room temperature) and building use

(warehouse storage)

Figure 1 Study Building and Layout of Roof Membrane Cap Sheet Color and Insulation Strategy

Polyiso

Hybrid

Stone wool

120’ 120’

Grey

White

Black

Polyiso

Hybrid

Stonewool

How We Have Been Monitoring

Temperature

Heat Flux

Relative Humidity

Moisture Detection

Displacement

Solar Radiation

Heat Flux Relative Humidity &

Moisture DetectionDisplacement

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

Tem

pe

ratu

re [

°F]

Tem

pe

ratu

re [

°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

Increased temperatures affect:

Membrane degradation/durability

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

Effe

ctiv

e A

ssem

bly

R-v

alu

e -

IP U

nit

s

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

Ro

of

Mem

bra

ne

Me

tal

Deck

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

He

at F

lux

[W/m

²]

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

De

gre

e D

ays

[°C

·day

s]

Dai

ly E

ne

rgy

Tran

sfe

r [W

·hr/

m²

pe

r d

ay]

Monthly Average Daily Energy Transfer by Insulation Arrangement

ISO ISO-SW SW Heating Degree Days (18°C)

Ou

twar

dH

eat

Flo

wIn

war

dH

eat

Flo

w

Ou

tward

Heat

Flo

w

Inw

ard

Heat

Flo

w

Energy Consumption and Membrane/

Insulation Design

Energy modeling performed for a

commercial retail building (ASHRAE

building prototype template) to compare

roof membrane colour & insulation strategy

Included more realistic thermal performance of

insulation into energy models

Stone wool: Lower R-value/inch

Higher heat capacity and mass

Polyiso: Higher R-value/inch

(varies with temperature a lot)

Lower heat capacity

Lower mass

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

An

nu

al H

eat

ing

Ene

rgy,

kW

h/m

2

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

An

nu

al C

oo

ling

Ene

rgy,

kW

h/m

2

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

Rated R-values of insulation do not tell the whole story

about actual heat flow through roofs (and walls)

Surface colour (solar absorptivity, long-wave

emissivity), insulation type, thermal mass, latent

energy transfer all impact this

Durability & whole building energy consumption

impacts

Monitoring of long term movement, aged R-values,

membrane degradation, moisture movement and more

ongoing

rdh.com

Discussion & Questions

Graham Finch – [email protected] – 604.802.5205

Building Enclosures For the Future - Building Tomorrows Buildings Today

Engineering