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www.buildingsciencelabs.com

Material Selection Matters

Dr John Straube, P.Eng. Principal, RDH Building Science

Professor, School of Architecture University of Waterloo

Outline • Materials• Structural Systems• Enclosures

• Concrete• Steel• Wood

• Trends, Research and Field Experience

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Presentation copyright RDH Building Science Inc. 2016

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SOME MATERIAL SCIENCE

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Materials – Basic Review • Agents of material deterioration

– Water + Oxygen– UV– High heat / very cold– Fire

• Three primary material categories– Metallic

• Corrosion=oxidation– Polymer/organic

• UV, oxidation, high heat, cold, moisture (natural polymers)– Mineral/Ceramic

• Freeze-thaw, salt– Composite: made up of others

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Polymers: Carbon bonds

Asphalt– a modified natural polymer

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e.g. Minerals used to protect polymer from UV

Wood: a natural polymer

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Clay Brick: an BmeCtested mineralCbased product

Salt (+water)

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Stone: being dissolved slowly

THE CHANGING WORLD

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New Challenges / Trends • Faster construction & design cycles

– All weather construction• Congested sites

– i.e., urban & additions• More high-rise & multi-use• Better energy performance

– More on this later…• Climate change & resiliency• Design for maintenance & renewal

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Building Energy Use

• Growing demand from codes and somecustomers for lower energy use

• Actual measured performance beginning to playa role- game changer– Models vs reality– Code compliance vs performance

• Energy use is a SYSTEM and DESIGN issue nota material issue– Continuous insulation, air barrier are critical!

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Aside: Thermal Mass & Energy

Savings 2% 9%

RDH Study of Vancouver MURB

• Thermal mass can improve comfort, resiliency,and save energy

• Mass in exposed ceilingsis most valuable

• Exterior walls alsohelpful- but keepit inside

Aside: Embodied Energy • Operation / use comprises 80-90% of life-cycle

energy of common buildings• Material choice is a

small overall factor• Energy-efficiency &

design-efficiency are90-95%

• Durable buildings arelower GHG

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MATERIALS AND STRUCTURAL SYSTEMS

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Different Occupancies / Different Needs

• Residential– Compartments: fire, sound, odour– Many good internal partitions

• Concrete / CMU vs framed hollow• Office

– Wide open flexible spaces, lots of services– Concrete or steel with concrete topping

• Retail– Very few partitions

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Past: the last 50+ yrs

• Wood– Low-rise, single-family– Some three+ storey multi’s

• Masonry– Low- & mid-rise institutional/commercial

• Concrete Frame– Mid- & high-rise institutional/commercial/resid.

• Steel Frame– Low- to high-rise commercial (some instit.)

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Why?

• Why were those choice made?• Usually because the different choices were

deemed best for different needs• High-rise is more expensive than low-rise

– Higher loads, higher fire resistance, moredurability expectations

• None of the material properties has changed– Why are choices changing?– Labour, energy, performance expectations

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Future material selection

• Building designers need to change to meet– More labor efficient (price)

• Prefab

– Higher density means...• Taller buildings, people next to each other• Fire and sound more important!

– More energy efficient• More insulation, more airtightness, less thermal

bridges– Building in any weather, fast

• Prefabrication, less moisture sensitive 24

In the old days … Labour & Bme expensive

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Wood single-family housing

• Low-cost• Easy to escape in fire• Sufficient load capacity (if connected)• Separation for fire/noise by air gap or CMU

Hot-rolled Steel Frame

• Low weather sensitivity• Fast erection• Requires significant additional fire protection

esp. for taller buildings• Requires enclosure system (like all frames)• Requires partition system (like all frames)

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LowCrise spec. office buildingAddiBonal finish, fire protecBonand sound isolaBon needed

Site-cast Concrete Frame

• Integral Fire-proofing• Shear walls / floor can be excellent fire/sound

separating partitions• Cold-weather sensitive• Need to have repetition in formwork to be

economical

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InsBtuBonal buildingStrong, durable, fire/soundresistantFlexible floor planCold weather heaBng…

Concrete Masonry Mid-rise InvestorCowned buildingStrong, durable, fire/sound resistantFixed compartmentsMasonry= labour expensive, weather

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Insulated Concrete Forms

Emerging technologyIncludes enclosure thermal/airLess weather/formwork sensiBveFoam needs fire protecBon/finish

R"20 to R"40

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ICF • High rise practical – manage window widths

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Total Precast (MURB)

Waterloo, ABA Architects

Investor ownedFast erecBon, excellent fire sound separaBonLiZle weather sensiBvity

Sandwich Panel

R"20 or so

Fast erecBon, excellent firesound separaBonLiZle weather sensiBvityPefab w/windows in factory

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Tall Wood Buildings • Much closer framing

– Not practical much beyond 6 stories• Cross-Laminated Timber

– Can be used for tall building• Post-and-Beam

– Can easily be 10 storeys with big enoughwood

• Wood-frame infill– Any height structurally…

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Four+

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SixCStorey MidCRise Wood Buildings (Framed)

6 storeys is very different . . .

• Price rockets as the amount of wood doublesand triples

• Connections!

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Complexity

• Fire and soundseparation morechallenging withframedassemblies

Challenges with Mechanically Attached Air Barriers & Wind During Construction

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CLT- new kind on the block

• New: solid wood strips, cross laminated• Much stronger, heavier, more fire resistant• Much more costly

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Solid Wood:CLT

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High-rise Around the World

We can … • … but should we?

• Significant complexity to manage– Many layers, trades, details

• New challenges to overcome– Construction moisture– Shrinkage/movement– Fire

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Construction Moisture

• Taller buildingsexposed to morerain and snow

• More concernsre. waterstorage/damage

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Moisture Trapped in Wood

•

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•

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Finland

Prince George BC

Shrinkage • Cross-grain

woodshrinks

Site Protection

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Differential Shrinkage Out of the Comfort Zone

• Wood frame and masonry orconcrete walls (fire walls, stairwells,elevator core)

• Masonry cladding• Floor and roof penetrations

(plumbing, sprinkler pipes, tops ofmasonry walls)

• Different support structure (balconieswith exterior columns)

Windowsill Sliding Flashing to Accommodate Shrinkage

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Fire During Construction

• Can you get insurance?

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SOME ENCLOSURE ASPECTS

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Many ways to enclose …

Contractors perspecBve– PCL Constructors

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Ensure conBnuouswater & air barrier,insulaBon

Highly moisturetolerant and fireresistant system

Detailing penetraBonsconBnues to be a focusForgiving system

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Steel Stud Infill

• Significanton-site &on-wallwork

• Most insulationneeds to be onexterior

Steel Stud Infill

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Curtainwall

60around RC3 to RC4 including spandrels and have lots of hidden sealantPrefabricated/UniBzed but, modern curtainwalls, window walls are

Architectural Precast

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e

Federal ReserveMinneapolis MNHOK Architects

FBI HQBuffalo, NY

Commercial/RetailCalgary, AB

R"10to R"

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Modern ApproachHigh thermalExcellent air / waterDurable

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 Do n’t dothis!AvoidAir Gap!!ProvideconWnuous“convecWon”barrier inside(e.g., sealedgypsum, tapedboard foam,taped foil%face

Old, problemaWcdesign approachPoor thermalPoor air control

Wide Range of Aesthetics

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Waterloo Region CourthouseNORR Architects

R"10 to R25

Complete prefab highCperformance enclosure

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Fort McMurray, AB Integrally Insulated Wall Panels Windows Cast-in at Precast Plant

oh Straube

UBC / Sandwich panelArchitects KPMB & HCMA

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ICF & Cladding • Many

options• Drained

is bestbut EIFSis practical

• Beware:all openingsmust bedrained!

Window / Balcony Detailsare CriBcal! Drain opening.

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  This is apenetraWontoo!Beware “sBck

and peels”

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Wood Enclosure Options

RC20to R

C30+

Exterior

air barrie

r

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Challenges with Mechanically Attached Water Control Layer & Wind

FullyCadhered air & waterbarriers preferred for higherexposure

Poor/Limited Choices

772x8 stud wall

LowR"v

alue

Higher M

oisture

Risk

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Conclusions

• Different materials have different properties• Different projects have different needs• We can usually use all materials for all projects,

but …the best materials will depend on the project!

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Contact me at:

live@buildingsciencelabs.com

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RDH is committed to expanding building science knowledge through research, education, and collaboration among building science professionals. By promoting sound principles established through research, while working with on-the-ground industry partners, RDH aims to have a lasting impact on the quality and energy efficiency of the built environment.

Presentation copyright RDH Building Science Inc. 2016