BEC 20140509 Straube Roof

High&Performance&Roofs:&Durable,&Ecient,&Reliable&

Dr&John&Straube,&P.Eng.&University&of&Waterloo&

Dept&of&Civil&Engineering&&&School&of&Architecture&BuildingScienceLabs.com&

!buildingsciencelabs buildingscienceconsultinginc

High&Performance&

What&are&high&performance&roof&enclosures?&They&dont&leak&Enable&buildings&with&low&opera5onal&energy&&Provide&comfort&&&safety&Ensure&good&Indoor&Air&Quality&Last&a&long&5me&

How&to&achieve&

Dont&leak&No&holes.&&&

Insula5on&Easy.&&ASHRAE&90.1&+,&say&R30&or&more&

Air5ghtness&Provide&an&air&barrier&

Durability&Material&selec5on&and&system&design&

Building&Science&2008&&

&&Joseph&Ls5burek&&Roofs&5&

Roof!Enclosures!!They!put!up!with!a!lot.!

The&classic&Perfect&Enclosure&

Building&Science.com& 6&

1.&

2.&

3.&

4.&

Building&Science& &&&&&Enclosures&&&&No.&8&/&

The&Perfect&Roof?:&Protected&Membrane&Roof&

Some&owners&insist&on&it.&&Eg.&GSA&

Building&ScienceLabs&.com&&

&&Roofs&9&

Inverted&Roof&

Pros:& Preferred&approach& Exterior&insula5on&eliminates&thermal&bridges&

Protects&membrane& Cons:&

Added&weight&of&ballast& Can&only&use&XPS&

Building&Science&Labs& &&&&&Enclosures&&&&No.&10&/&&

Exposed&membranes& Most&common&solu5on& Pros:&

Lightest&weight& Wide&variety&of&insula5on&and&membranes&

Cons:& Exposed&membrane!&

Building&Science&Labs& &&&&&Enclosures&&&&No.&11&/&&

Building&Science& &&Roofs&12&

Its&a&roof,&not&a&pool&


Money&spent&on&roof&slope&is&one&of&the&best&bargains&in&the&construc5on&business&Wayne&Tobiasson,&CRRL&&


Its&a&roof,&not&a&ice&rink&


This&is&not&a&soluOon&

Slope& &&

2%&is&a&good&design&value&for&membrane& Account&for&roof&sags:&long&span&steel&ohen&sags&more&than&slope&

Be&careful&of&roof&drains&at&columns&

Building&ScienceLabs&.com&&

&&Roofs&16&

From:&Straube,&J.F.&High(Performance0Enclosures,&2012.&

Vapor&Control:&What&is&the&permeance&of&the&insula5on?&Self$Drying&roof?&Construc5on&Moisture?&

Exposed&Membrane&

Single$ply&vs&Mul5$ply?& Factory&made&or&site&made?& Durability&of&materials&

Polymer&Mineral&Metals&

Durability&of&polymers.&

Best&UV&Protec5on:&rocks&

But,&you&need&to&hold&down&to&resist&wind&

Building&Science&.com&&

&&Roofs&19&

A&tradiOonal&roof&



Super!durable!membrane!.!

Building&Science.com&&

&&&Roofs&21&

White&roofs&

Lower&heat&gain:&great!& Reduce&stress&on&exposed&roof&membranes& But:&Reduces&drying&out&of&roof& Thus:&Require&bemer&moisture&control!&

Air&barrier&Construc5on&moisture&

Building&Science.com& &Roofs&22&


White&roofs:&the&coming&storm&

Where!is!the!air!barrier?!

White&Membrane&stay&cold&

&&

Black&Membrane&

White&Membrane&

Building&Science&.com&

&&Roofs&27&


Low$level&air&barriers&

Roof&membranes&can&be&air&barriers& In&prac5se,&a&deck&level&air&barrier&is&more&reliable,&easier&to&control&Other&benets&include&secondary&roof&during&construc5on&and&re$roong&

Building&Science&.com&& Roofs&28&

&&&No&deck&Air&Barrier&&&+&No&fully$adhered&membrane&+&White&Roof&=&accumula5on&of&moisture&&&failure&

Building&Science&&

&&Roofs&29&

High$performance,&air&and&vapor&barrier&&

Deck&Cover&Board& Seal&the&joints,&or&cover&the&whole&surface& Gypsum&is&vapor&permeable&

Air&Barriers&

Stone&wool&hybrid&roofs& Use&the&deck$level&polyiso&as&vapor&control& Seal&joints&to&form&an&air&barrier&

Building&Science&

A&cheap&air&barrier&

Courtesy:&Andy&Shapito&

Special&Applica5ons&

Swimming&pools&Esp&in&cold&climates&

Freezer&buildings&Esp&in&hot&humid&climates&

Badly&(normally)&operated&hospitals& MUST&have&a&deck&level&air&barrier&

Sealed&at&all&edges,&penetra5ons!&


&&Roofs&34&

Details& Penetra5ons&&and&edge&&of&roof&

AIR&


&&Roofs&36&

Air&sealing&details&

May&need&plas5c&pipe&sec5on&to&reduce&thermal&bridge&


&&&Roofs&37&


Parapets&


&&

Building&Science.com& &Roofs&39&From:&Straube,&J.F.&High(Performance0Enclosures,&2012.&

Vapor&Control?&

&&

Vapor&Control?&





Condensa?on!can!s?ll!occur.!

Drying&cold&parapets&

&&

Vapor&permeable&peel$s5ck&diusion&ohen&most&prac5cal&&


&&


Conclusions&/&Summary&

Cool&roofs&are&cooler& Condensa5on&risks&increase& Now&need&a&deck$level&air&barriers& Fully$adhered&membranes& Vapor&Control,&not&Vapor&Barriers&

At&BuildingScience.com&

High Performance Enclosures

DESIGN GUIDE

JOHNSTRAUBE

FORINSTITUTIONALCOMMERCIALAND INDUSTRIALBUILDINGSINCOLD CLIMATES

FRONT PHOTO: ALEX LUKACHKOBACK PHOTO: BUILDING SCIENCE CORPORATION

The first part of the Design Guide provides the building science theory that underpins the designer's work to control water, heat, air and vapor movement across the skin. Specific details, such as parapets, grade-level connections, window installation, and curtainwall system integra-tion, are provided for different types of high performance enclosure systems in the second part of the book. A generous amount of additional supporting information on energy and building science issues is provided in the appendices.

High Performance Enclosures: Design Guide for Institutional, Commercial and Industrial Buildings in Cold Climates provides guidance for architects and building enclosure engineers working to meet the growing need for buildings that have significantly lower operational energy consumption. John Straube addresses a range of practical questions about low energy building enclo-sures that save energy while simultaneously improving durability, comfort, and rain control: How much of an impact can the enclosure, massing, and orientation have? How much glazing is appropriate and what options are available? How much does thermal bridging matter and how can it be minimized at difficult structural details? How does one detail thick layers of continuous insulation outside of steel stud walls? Can layers of insulating sheathing reduce the risk of moisture damage?

High Performance Enclosures

ABOUT THE BOOK

JOHNSTRAUBE

High P

erformance E

nclosures STR

AU

BE

9(5,)

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BEC 20140509 Straube Roof