b'Concrete DecksOPTION VAPOUR RETARDER/ROOFING SYSTEM CONSTRUCTION CRITICAL CONSIDERATIONSAROOF MEMBRANE COVER BOARDADHESIVE ADHESIVETHERMAL INSULATIONMechanically fastened venting base sheet, attached using pre-ADHESIVE drilled stainless-steel fasteners Over this base sheet, install an adhered vapour retarder (e.g., The long-term durability of the fasteners into a wet deckheat-welded SBS membrane or a two-ply, hot-moppedThe maximum uplift resistance of the roofing system is vapour retarder) limited by the use of a base sheetTHERMAL INSULATIONADHESIVEInsulation and roofing membrane adhered over theADHERED VAPOR RETARDER (HEAT-WELDED SBSMEMBRANE OR 2-PLY HOT-MOPPED VAPOR RETARDER) vapour retarderVENTING BASE SHEETPRE-DRILLED STAINLESS STEEL FASTENERSCONCRETE DECKBOPTION AROOF MEMBRANE COVER BOARDADHESIVE ADHESIVETHERMAL INSULATIONADHESIVE6-mil polyethylene sheet vapour retarderThe long-term durability of the fasteners into a wet deck Mechanically fastened venting base sheet, attached using pre-The maximum uplift resistance of the roofing system is drilled stainless-steel fasteners limited by the use of a base sheetTHERMAL INSULATIONInsulation and roofing membrane adhered over the base sheetThis configuration results in approximately one fastener ADHESIVE through the vapour retarder every square footPRE-DRILLED STAINLESS STEEL FASTENERSVENTING BASE SHEET6-MIL POLYETHYLENE SHEET VAPOR RETARDERCONCRETE DECKOPTION BCROOF MEMBRANE COVER BOARDADHESIVE ADHESIVETHERMAL INSULATION6-mil polyethylene sheet vapour retarder The long-term durability of the fasteners into a wet deckADHESIVE Insulation attached through the vapour retarder into the The uplift resistance of the roofing system is dependent on concrete deck using stainless steel fasteners or spikes the attachment of the first layer of insulation Over the first layer of insulation, adhere additional insulation The attachment of the insulation is through theTHERMAL INSULATION (if/as required) and then the roofing membrane vapour retarderSTAINLESS STEEL FASTENERS OR SPIKES6-MIL POLYETHYLENE SHEET VAPOR RETARDERCONCRETE DECKVapour retarder/roofing system constructions and critical considerations.OPTION C Table 3: (Continued on page 11.) mance. Perhaps this may be lessexhaustive; for example, the use ofconcrete deckparticularly when ofaconcernwherethevapouralightweightinsulatingconcretesaidconcreteisinstalledovera drive is less, such as Atlanta as op- fill may be a solution that providesnon-venting substrate. posed to Minneapolis. a substrate that is more amenable There are several options avail- to mechanical attachment.Footnotes Commercial and Residential Roofing ablethatmaybeacceptableandWhentakenintoconsider- i Mark S. Graham. Moisture in Trinity Roofing Ltd. specializes in a variety of roofing applications and meet the needs for a roofing system.ation with the cost of failure, weConcrete Roof Decks. Professional waterproofing for residential, commercial and institutional buildings. For clarity, Table 3 identifies thesesuggest that professionals utilizeRoofing. September 2017. options, in no particular order. industry practices that are beyondii SPRIIndustryInformation Phone: 416-630-9213URL: www.trinitycanada.comtherecommendationsgenerallyBulletin No. 2-13, Moisture Con-Fax: 416-630-1722 Email: info@trinitycanada.comDiscussion offeredandtakeintoaccountcerns in Roofing Systems Applied Consideringthequestionsan environment that may not beOver Lightweight Structural Con-raised about the performance ofconducivetoamoretradition- crete Roof Decks. August 2013.vapour retarders installed over aally installed vapour retarder oniii Colin Murphy, RRC, FRCI. aconcretedeck.Untilfurther concretedeckthatcontainsanunderstanding and knowledge areWetConcreteDecks:Problems unacceptableamountofmois- developedthroughresearchandandPracticalSolutions.Interface. ture, it is prudent for roofing pro- in-situ experience, roofing systemAugust 2006; Joe Schwetz. Risks fessionals to take care in their de- designersshouldconsidertheirof Roofing Over Concrete Decks. cisions. Each of these options hasresponsibility for the building en- Interface.July2014;GregoryR. its own limitations that must beclosures performance and incor- Doelp, PE and Philip S. Moser, PE, consideredandweighedagainstporate the potential for moistureLEED AP. Reducing the Risks of the specific project requirements.into their designs when specifyingMoisture Problems From Concrete In addition, the above list is nota roofing system installed over aRoof Decks. Interface. April 2014.10ONTARIO ROOFING NEWSISSUE 2 2020 THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ORN'