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?

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 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

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

-20 -10 0 10 20 30 40 50 60

Mean Temperature of Insulation (°C)

Long-Term R-value per Inch for Various Samples of Insulation vs. Mean Temperature

Mineral/Glass FiberBatt Low

Mineral/Glass FiberBatt High

Mineral Fiber RigidBoard

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

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)

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

Climate Zone

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

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

Roof – AZc: 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

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

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 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

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

16.8 33.6 50.4

(ft2 ·

°F·h

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

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"

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"

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

16.8 33.6 50.4

Cladding Attachment R-values – It Matters!

Percent Thermal Degradation of Exterior Insulation

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

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)

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

Polyiso

Hybrid

Stone wool

120’ 120’

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?

May Jun Jul Aug Sept Oct Nov Dec Jan Feb Mar Apr

rature [°F]

rature [°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

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

Heat Flow – Variation with Insulation Strategy

SENSOR CODING: SW - stone wool, ISO – polyiso, ISO-SW - hybrid

-‐25

-‐20

-‐15

-‐10

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Heat Flux [W

Heat Flux Sensors

G-‐ISO HF

G-‐ISO-‐SW HF

G-‐SW HF

Net Annual Impact of Insulation Strategy

-‐150

-‐100

-‐50

May Jun Jul Aug Sept Oct Nov Dec Jan Feb Mar Apr Annual

Degree

Days [°C·∙da

Daily Ene

rgy Tran

sfer [W

·∙hr/m² p

er day]

Monthly Average Daily Energy Transfer by Insulation Arrangement

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

OutwardHe

at Flow

InwardHe

at Flow

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?

1 -‐ Miami 2 -‐ Houston 3 -‐ San Francisco 4 -‐ Baltimore 5 -‐ Vancouver 6 -‐ Burlington VT 7 -‐ Duluth 8 -‐ Fairbanks

al Heatin

ergy, kWh/m

Climate Zone

Black -‐ Aged Polyiso

Black -‐ Stonewool

Black -‐ Aged Hybrid

White -‐ Aged Polyiso

White -‐ Stonewool

White -‐ Aged Hybrid

1 -‐ Miami 2 -‐ Houston 3 -‐ San Francisco 4 -‐ Baltimore 5 -‐ Vancouver 6 -‐ Burlington VT 7 -‐ Duluth 8 -‐ Fairbanks

al Coo

ling En

ergy, kWh/m

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

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