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Building Enclosures – A Systems Approach for Tall and Small Wood pp

Buildings

2015 T W d S l i F i2015 Toronto Wood Solutions Fair

Alex Lukachko, M.Arch.Principal, Building Science SpecialistRDH Building Science Laboratories

Kurt Koch, P.E.VP Engineering and Innovation

Huber Engineered Woods

1buildingsciencelabs.com huber.com

Canadian Wood CouncilG063

Building Enclosures - A Systems-Approach for Tall and Small Wood BuildingsBuildings

Kurt Koch, P. Eng and VP Engineering and Innovation at Huber Engineered Woods LLC Alex Lukachko, Senior Associate, Building Science Consulting Inc.

November 24 2015November 24, 2015

Credit(s) earned on completion of this course will be reported to AIA

This course is registered with AIA CES for continuing professional

CES for AIA members. Certificates of Completion for both AIA members and non-AIA members are available upon

education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by themembers are available upon

request.approval or endorsement by the AIA of any material of construction or any method or manner ofhandling using distributing orhandling, 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.

CourseDescription

We are rapidly changing the way that we build enclosures for wood buildings.  Code requirements for more insulation, for example, are pushing towards continuous exterior insulation.  Performance programs like ENERGY STAR are requiring new approaches to air‐tightness We are also building larger wood buildings with smallerapproaches to air‐tightness.  We are also building larger wood buildings, with smaller units ‐ currently all of the way up to six stories.  

All of these changes also change the way that our wood buildings work from a moisture perspective ‐ both in the control of rain water penetration and the movement of moisture through the wall.  Put together, these changes present some interesting building science challenges for enclosure design and the selection of materials. 

We’ll work through these issues one‐by‐one and outline the development of a whole system approach to be used for both tall and small wood buildings.

LearningObjectives

Key learning points:

• Participants will understand factors affecting the way building enclosures for wood buildings are built and how these factors are catalysts for rapid change in the industry. 

Key learning points:

• Code requirements and performance programs will be reviewed.

• The way that wood buildings work from a moisture perspective ‐ both in the control of rain water penetration and the movement of moisture through the wall will be considered.

• Participants will learn about the building science challenges for enclosure design, work through issues one‐by‐one, and outline the development of a whole system approach that can be used for both tall and small wood buildings.

Building Enclosures – A Systems Approach for Tall and Small Wood

Buildings

1. Changes and Challenges I d Th l l• Increased Thermal control

• Airtightness Requirements• Higher densityg y

2. Solutions and a Systems Approach

1. Case Study: Active House

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#1 – Increased Insulation#1 Increased Insulation

• Code changes areCode changes are– increasing total R-value– changing our R-value calculationg g

• Creates challenges for:– cladding attachment– drainage plane integration– window and door trim– inspections during construction

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Traditional R-value Calculations

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Thermal Resistance TerminologyThermal Resistance Terminology

• Rated R-value– The theoretical R-value of the insulation. Sometimes

called the Nominal or Advertised R-value. E.g., R-13 batt; R-6/inch

Eff i R l • Effective R-value – The functional R-value of the insulation as installed in

the wall assembly, de-rated if necessary due to thermal bridging at framing membersthermal bridging at framing members.

• Total R-value– The actual R-value of the wall assembly including not

only the Effective R value of the insulation but also only the Effective R-value of the insulation but also the R-values for other wall system components such as materials, air spaces, air films, etc.

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Best-case R-values for Stud WallsBest case R values for Stud Walls

10www.BuildingScience.com

Thermal Comfort?

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Reduce Unnecessary Thermal Bridging

12Where 4 is Good

Reduce Unnecessary Thermal Bridging

13Where 5 is Better

Reduce Unnecessary Thermal Bridging

1410 Has to Be Just GREAT!

State of the Art: the “Perfect Wall”State of the Art: the Perfect Wall

• Support structure is anything – structure is anything that works

• Control continuity– Rain control layery

• Perfect barrier• Drained with gap• Storage

– Air control layer• Air barrier

– Thermal control layer• Aka insulation, radiant

barriers– Vapor control layer

• Retarders, barriers, etc

• Finish – interior and exterior

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– interior and exterior

Lstiburek – Various; Straube – “High Performance Enclosures”

Fire Control may be neededSound Control optional

Adding Insulation to Wood‐Frame Walls

Baseline

Exterior Insulation: R‐20 to R‐40+ effective• Constraints: cladding attachment, wall 

2x6 w/ R‐22 batts = ~R‐16effective

thickness• Good durability

Deep or Double Stud: pR‐20 to R‐40+ effective• Constraints wall 

thickness• Fair durability, 

sensitive to air/vapour

Split Insulation: R‐20 to R‐40+ effective• Constraints: cladding 

attachmentattachment• Good durability with proper 

design

17Fieldgate Homes

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#2 – Increased Airtightness#2 Increased Airtightness

• Current home performance standards Current home performance standards require testing to meet target– low-rise – whole building airtightness– mid-rise – suite compartmentalization

• Code may change to require testing

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What the Code Says Now (SB-12)What the Code Says Now (SB 12)

2.1.1 – Prescriptive Compliance PackagesH d fi d f h P kHard to find - part of the Package

2.1.2 – Performance Compliance(5) Except as provided in Sentence (6), for the purpose of Clauses (3)(a) ( ) p p ( ), p p ( )( )and (3)(b), the air leakage rate of a dwelling unit may be assumed to be:(a) 2.5 air changes per hour at an air pressure differential of 50 Pa for

detached homes, and(b) 3.0 air changes per hour at an air pressure differential of 50 Pa for

h d h attached homes. (6) For the purpose of Clause (3)(a), values less than Sentence (5) may be used provided that the values are verified with air leakage tests as conducted in accordance with the requirements of Clause 12.2.1.2.(3)(a) of Division B in the Building Code of Division B in the Building Code.

2.1.3 – Other (means Energy Star)

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What the Code Says Now (SB-10)What the Code Says Now (SB 10)

5.4.3 Air Leakage 5.4.3 Air Leakage 5.4.3.1 Building Envelope Sealing. The following areas of the building envelope shall be sealed, caulked, gasketed, or weather-stripped to minimize air leakage:(a) joints around fenestration and door frames,(b) junctions between walls and foundations, between walls at building

corners, between walls and structural floors or roofs, and between walls and roof or wall panelsand roof or wall panels,

(c) openings at penetrations of utility services through roofs, walls,andfloors,

(d) site-built fenestration and doors,( ) ,(e) building assemblies used as ducts or plenums,(f) joints, seams, and penetrations of vapor retarders,(g) all other openings in the building envelope.

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Air Barriers RequirementsAir Barriers Requirements

• Requirements for an Air Barrier SystemRequirements for an Air Barrier System– Continuous (most important)

– Strongg

– Stiff

– Durable

– Air Impermeable (least important)

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Continuity is KeyContinuity is Key

Interior Air Barrier Approach Exterior Air Barrier Approach

Interior connection to airbarrier at ceiling/attic floor

Complex transition at floors and interior walls

Transition from outside to insideat vented attic; Low-slope roofall exterior connection

No interruption at floors and interior walls

Connection to below-gradeair barrier components Connection to below-grade

air barrier components

23

Stiffness is ImportantStiffness is Important

negative pressure gust positve pressure gust

housewrap balloons outwards

air flows from interior into stud space

housewrap pressed tight to sheathing

air flows out of stud space to interiorp p

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Air moves more vapour than diffusion!Air moves more vapour than diffusion!

Vapor diffusion onlyLow (Class III) vapour control

Air leakage onlyHigh (Class I) vapour controlLow (Class III) vapour control High (Class I) vapour control

0.5 L / month 22 L / month

25Calculations for a single stud bay, 8 ft tall, 16” wide

0 5 / /

26Insulation and Air Barrier / Vapour Barrier – Must be Perfect

Condensation & Dryingy g

27

#3 – Increasing Housing Density#3 Increasing Housing Density

• Challenges for all enclosuresChallenges for all enclosures– acoustic separation within units– acoustic performance of enclosure (urban noise)p– fire rating for exterior wall assemblies

• Challenges for taller construction– fire protection during construction– small, slow urban brownfield sites– wood shrinkage– increased rain and wind loads

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* 10:40 – Track 1 – Tall Wood Enclosures Lessons Learned – Graham Finch

Increasing Housing DensityIncreasing Housing Density

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Challenges to AddressChallenges to Address

• increasing thermal control requirementsg q– cladding attachment– drainage plane integration

d d d– window and door trim– inspections during construction

• increased airtightness requirements• increased airtightness requirements– quality control– moisture (drying and condensation control)y g

• higher housing density– increase construction speed

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– acoustic performance

SOLUTIONS – A SYSTEMS SOLUTIONS A SYSTEMS APPROACH

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Path to a Systems SolutionPath to a Systems Solution

1. Move insulation towards the exterior– lower moisture risk, allows further increase

2. Reduce framing factor – higher Effective R-value, more insulationhigher Effective R value, more insulation

3. Air barrier to exterior– construction speed and quality

4 Allow drying to both sides4. Allow drying to both sides

Remaining choices:g- cladding attachment- air barrier material/system options

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Cladding Attachment Choices

Longer cladding Fasteners directly through rigid insulation (up to L h h insulation (up to 2” for light claddings)

Long screws through vertical strapping and rigid insulation creates truss (8”+) – short l ddi f i

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cladding fasteners into vertical strapping Rigid shear block type

connection through insulation, cladding to vertical strapping

Air Barrier Choices

Air Barrier System Options:– Sealed Polyethyleney y

– Airtight Drywall

– Spray Polyurethane Foam

d h ll h d– Taped Mechanically AttachedSheathing Membrane

– Self-Adhered or LiquidApplied Sheathing Membrane

– Sealed Sheathing

34

Wood-frame Exterior Air Barrier Trends

• Trend towards exterior air barrier approaches (at sheathing plane) relying on rigidity of wood/gypsum sheathingo g d ty o ood/gypsu s eat g

• Sealed sheathing membrane approach – Self-adhered Membrane, $$$

Liquid/Fluid Applied $$$– Liquid/Fluid Applied, $$$

– Mechanically Attached (Taped & Sealed), $

• Sealed sheathing approach ( l d/OSB/ )(plywood/OSB/gypsum)– Sealed joints (good sealant or tapes), $$

• Use of interior approaches not common– Sealed poly not appropriate for exposure

– Airtight drywall not widely used

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CASE STUDY – ACTIVE CASE STUDY ACTIVE HOUSE PROTOTYPE

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Active House – Etobicoke

37 of 4A Case Study

Active House – A New Building Standard

• Buildings that give more than they takeBuildings that give more than they take• Active House is a vision of buildings that create healthier and more comfortable livescreate healthier and more comfortable lives for their occupants without impacting negatively on the climate moving us towardsnegatively on the climate – moving us towards a cleaner, healthier and safer world.

New Buildings– New Buildings– Renovated Buildings

Active House – Performance Criteria

• Occupant’s Indoor Comfort – creates h lthi d f t bl i dhealthier and more comfortable indoor conditions  for the occupants, ensuring a generous supply of daylight and fresh air. 

• Energy Consumption Minimized – energyEnergy Consumption Minimized  energy needed is supplied by renewable energy sources integrated in the building or from the nearby collective energy system and l t i it idelectricity grid.

• Environmental Conservation is Considered – has a positive impact on the environment through a focused use ofenvironment through a focused use of resources, and its overall environmental impact throughout its life cycle.

Active House – EtobicokeGeneral InformationGeneral Information

• Wood‐framed construction• 2‐framed floors above a reinforced concrete foundation 

• Shingle roof• Walls clad with brick, metal panels and EIFS 

• Solar Thermal panels

Roof Framing SectionRoof Framing Section

• Prefabricated wood trusses (14” raised heels)

• 14” blown‐in insulation (R 50)(R‐50)

• Insulated exterior wall sheathing with integrated g gWRB

• Vapor retarder on inside f f llface of walls

Floor Framing SectionFloor Framing Section

• 14” I‐joistsj• Rockwool insulation at rim• Insulated exterior wall 

sheathing with integrated WRB

• Vapor retarder continuousVapor retarder continuous through floor cavity

Footing/Foundation DetailFooting/Foundation Detail

• 2” XPS underslab, 1” rigid at slab edge10” R i f d• 10” Reinforced concrete foundation wall

• R‐20 blanket insulationR 20 blanket insulation on interior with continuous interior vapor retardervapor retarder

• Drainage mat and waterproofing on the p goutside

Wall Framing SectionWall Framing Section

• 2x6 at 16” o c studs• 2x6 at 16  o.c studs• R‐24 Batt• Insulated exteriorInsulated exterior 

wall sheathing with integrated WRB

• Vapor retarder along inside face of the walls

Active House – Etobicoke Details

Component DetailsWindows Triple glazeWindows Triple glaze 

North, East and South U= 0.2, SHGC = 0.42West  U=0.17, SHGC = 0.24

Furnace 98% furnace w/ heat pump, Nat gas backup

Ventilation HRV

AC Heat Pump 16 SEER

Hot Water .96 EF Tankless

Power‐Pipe Hot water heat recovery from drain water

Smart House Automation

Controls blinds, windows and skylights

Electrical 100% LED or CFLElectrical 100% LED or CFLAll appliances are ES

ACH 2.4 ACH 50

EnerGuide 90

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Front Elevation

Rear ElevationRear Elevation

North Side Elevation

South Side Elevation

Thank youThank you

This concludes The American Institute of Architects Continuing Education Systems Course

Canadian Wood CouncilWood WORKS! Ontario

www.cwc.cawww.wood-works.ca

Contact us at:

[email protected]@buildingsciencelabs.com

Download the presentation in .pdf format from:

buildingsciencelabs.com/presentations

Huber Engineered Woods LLC (HEW) creates innovative specialty products—AdvanTech®flooring and ZIP System® roof and wall sheathing—that provide residential and commercialbuilders with improved performance, easy installation and greater strength. Therecognized leader in specialty engineered woods in the United States HEW brings together

RDH Building Engineering Ltd. and Building Science Consulting and Labs Inc. have merged.Effective November 1, 2015, we are operating as one integrated firm. The merger brings

recognized leader in specialty engineered woods in the United States, HEW brings togethera team of professionals with experience in research and development, technical servicesand manufacturing to create products that solve specific problems.

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, , p g g g gtwo of the leading building science firms in North America together to provide acombination of cutting-edge research with leading design and implementation capabilities.The result is a unique offering for our clients–an ability to explore new and innovative ideasbased on science and our practical knowledge of what can be built. We are excited aboutthe possibilities as we launch the new firm.