b'Reprinted with permission from Professional Roofing magazine.N ewly poured and, in some instances, existing structuralOver time, the roofing industry has advanced its knowledge of concrete roof decks present unique moisture migration problems for the roofing industry. This issue is not newWe have you insulated.the industry has been facing it for years, and several authorsmoisture in concrete roof decks and how to best address it. And and I have written numerous articles in Professional Roofing and other publications about it. Over time, the roofing industryWhatever your roofing NRCA has updated its best practice guidelines for successfully has advanced its knowledge of moisture in concrete roof decks and how to best address it. And NRCA has updated its best practice guidelines for successfully dealing with structural con- dealing with structural concrete roof decks moisture.crete roof decks moisture. application or timeline.Concrete BasicsThere are three general types of concrete: normal-weight structural concrete, lightweight structural concrete and light- We have you insulated. weight insulating concrete.Normal-weightstructuralconcreteiswhatmostpeopleWe have you insulated. think of as concrete; it has a density of about 150 pounds perWe have you insulated. cubic foot and, when properly designed, can carry structuralWhatever your roofing We have you insulated. loads.LightweightstructuralconcretehassimilarstructuralWhatever your rWhatever your roofing oofing load-carrying capabilities as normal-weight structural concrete,application or timeline.Whatever your roofing We have you insulated. We have you insulated. but it has a density in the range of about 85 to 120 pcf. application or timeline.application or timeline.Both normal-weight and lightweight structural concrete areWe have you insulated. Whatever your roofing application or timeline.produced by mixing large and small aggregates, Portland ce- Whatever your roofing ment, water and, in some instances, other additives such as flyWhatever your roofing application or timeline.ash and various chemical admixtures. Admixtures can add en- application or timeline.application or timeline.trained air to the concrete, accelerate the concretes curing, re- We have you insulated. tain the concretes excess moisture and/or lengthen concretesWe have you insulated. finishing time. The use of admixtures typically is not visuallyWhatever your roofing identifiable in the field; microscopic analysis usually is neces- Whatever your roofing sary for post-application identification of admixtures. application or timeline.The primary difference in composition of normal-weightapplication or timeline.structural concrete and lightweight structural concrete is the type of large aggregates used. Normal-weight structural concrete contains normal-weight aggregates such as stone or crushed gravel, which are dense and typically absorb no more moisture than about 2% by weight. Lightweight structural concrete uses lightweight, porous aggregates such as expanded shale, which will absorb about 5% to 25% moisture by weight. Lightweight aggregate needs to be saturated with moistureits often sub-merged in ponds during storagebefore concrete batching. As a result, lightweight structural concrete inherently contains much more water than normal-weight structural concrete.Normal-weight structural concrete and lightweight structur- Readily available in Ontario,Using proprietary software, we can provide positive slope to drain for al concrete are used in cast-in-place concrete roof decks with re- Readily available in Ontario,Using pUrosipnrgie ptaroryp srioefttary re, fw arewe caid providiv p ositpiv t osldpra to d in for Readily available in Ontario,waso twe ca,n provn e positee slo eeo ein f orr aPlastiSpan is used as theall types of layouts for new and re-roofing applications. PlastiSpan movable forms; composite roof decks where metal form decksPlastiSpan is used as theall typeasl lo tfy plaeyso uotfs l afoyor untesw f oarn nde rwe -aronodfi rneg-r oapofipnlicga atipopnlsic. aPtilaosntsiS. Ppalans tiSpan PlastiSpan is used as the remain in place; precast and prestressed concrete planks andinsulation component in manyinsulation may be used in either non-combustible or combustible insulation component in many insulation component in manyinsulatiionns umlaatyio bn em uasye db ein u esiethde irnneoitnh-ecro nmobnu-csotibmleb uosrt cibolem obru csotibmleb ustible Readily available in Ontario,Using proprietary software, we can provide positive slope to drain for tees; and as a concrete topping surface overReadily available in Ontario,Using proprietary software, we can provide positiionocompo adra a nomber of ofitswa ve slope to in f r precast concreteroof assemblies. Whether built up,U sntr auctionrylais ns enstee ction and is nent innensinberifsulation component in a number of roof assemblies. Whether built up, construccotn iopropnridetias co as thdinsulae onuatmplisted aumheunReadily available in Ontario,all Ussiinngg p tddlis r ruas th t iins clo tt oroof assemblies. Whether built up,e,,wweeccaannpprroovvidideeppoossititiviveesslope to dlope to drraainin f oforrReadily available in Ontario,roprietary softwarePlastiSpan is used as the types of layouts for new and re-roofing applications. PlastiSpan planks and tees. single plysingle ply, modified bitumen or , modified bitumen orULC laULCor new and re-roofinglio s n blies.ns. PlastiSpann n PlastiSpan is used as theall types of layouts f ctfor y toraro ualsroma applicatio iicationlss. Plas iS iaforPlastiSpan is used as theU l nd Faa d F aM to lMuotfan eobsse.mapplsilcation ope to tdrapReadily available in Ontario,itygp epsro on rli aytaocuu forw w s r a - e fi a po tive s . PlastiSpan PlastiSpan is used as theale ryt suner nd e rproofivnigdg eppalsl tnypes opfs fyoftr naeew, awedc rf n ooinsulation component in manyayouts LC and Factory Mutual roof assemblies. U e-rOnce placed, normal-weight structural concrete and light- single ply, modified bitumen orton mayo be u ed i on-combustible ustible o bust bus t bleale ninsulation may be used in either non-combustible or combustible standing seam roofing systems, oofing systems,insWith manufacturing facilities in Kitchener and Ajax, and a Winnipeg standing seam r With manufacturing facilities in Kitchener and Ajax, and a Winnipeg insulation component in manymay be used in either n heno -comor comco m ible ipinsulation component in manyintuyl la n ei er r on o sPlastiSpan is used as theateiiosn omf laayybuets u fssoerd n ienwe iatthnd e-rno-ocfionmgb baupsptilbiclea t oiorrn cs. mPlbaustitSibinsulation component in manyinsulationallsu p rnroof assemblies. Whether built up,construction and is listed as the insulation component in a number of r standing seam roofing systems,tion d as With manufacturing facilities in Kitchener and Ajax, and a Winnipeg weight structural concrete cannot easily be differentiated fromwe can meet design and deliveryfacility delivering to Thunder Bay and Northwestern Ontario, we havefwe can meet design and deliveryic facility delivering to Thunder Bay and Northwesterin a number ofu o ible nec n Ontario, we have roof assemblies. Whether built up,construc and is listed as the insulationb c st po or n im a u u ib beroof assemblies. Whether built up,nosnuslattriuocnt imona ya nbdeiuss leisdte idneaisth tehre n inosnu-claotimon commponentot n bnstm ler ooof assemblies. Whether built up,construction and is listethe insulation component in a number of insulation component in many single ply, modified bitumen orULC and Factory Mutual roof assemblies. timelines on pr c ryed.each other in the field. Visual identification is possible using mag- timelines on projects of any scale. ojects of any scale. Ontario coverUoLnCOntario covered.a M uluisttutueaadll rraoosoo ftf h aaess sisneesmmublbalilteiieossn component in a number of roof assemblies. Whether built up,ULCstaarunncddtiFFoancc attoonrdy issingle ply, modified bitumen orMwe can meet design and deliveryfacility delivering to Thunder Bay and Northwestern Ontario, we have single ply, modified bitumen or single ply, modified bitumen orULC and Factory Mutual roof assemblies. standing seam roofing systems,With manufacturing facilities in Kitchener and Ajax, and a Winnipeg nification, typically a microscope used by a trained technician. single ply oofing systems,ULC and Factory Mutual roof assemblies. standing seam r, modified bitumen or oofing systems,With manufacturing facilities in Kitchener and Ajax, and a Winnipeg standing seam r With manufacturing facilities in Kitchener and Ajax, and a Winnipeg roofing pro- timelines on projects of any scale.Ontario covered.we can meet design and deliveryfacility delivering to Thunder Bay and Northwestern Ontario, we have Lightweight insulating concrete, which manystanding seam roofing systems,With manufacturing facilities in Kitchener and Ajax, and a Winnipeg we can meet design and deliveryUstanding seam roofing systems,facility delivering to Thunder Bay and NorthwesterReadily available in Ontario,sing proprietary software, we can provide positiven Ontario, we haven Ontario, we have slope to drain for we can meet design and deliveryWith manufacturing facilities in Kitchener and Ajax, and a Winnipeg facility delivering to Thunder Bay and Northwestertimelines on projects of any scale.Ontario covered.fessionalsarefamiliarwithasaninsulating,we can meet design and deliveryfacility delivering to Thunder Bay and Northwestern Ontario, we have slope-to-drainwe can meet design and deliveryU sn lo.p Pela tsot idSrpan ain for Readily available in Ontario,facility delivering to Thunder Bay and Northwester sstimelines on projects of any scale.alsPlastiSpan is used as thel itnygp epsr oopf rliaeyted.aoruyt ss ofoftrw naerwe,awnedcraen-r oporofivnigd ea pppolicitaivtieon Ontario, we have timelines on projects of any scale.Ontario coverPlasti-Fab helps cr Ontario covered.Plasti-Fab helps create lasting communities by supplying Expanded Polystyreate lasting communities by supplying Expanded Polystyrene (EPS) prene (EPS) products to construction and civil oducts to construction and civil PlastiSpan is used as thea srange of 20timelines on projects of any scale.inll tuylpateiosn o mf laayyed.o buets u fsoerd n ienw e iathnedrrneo-rno-ocfionmgb aupsptilbiclea toiorn cso. mPlbausstitSibplean roof deck topping, typically has a density in thetimelines on projects of any scale.Ontario covered.insulation component in manyOntario coverinfrastructurinfrastructure projects. As the only vertically-integrated EPS company in North America, we are projects. As the only vertically-integrated EPS company in North America, we are leading the industry with e leading the industry with insulation component in manyinosnuslatrtuiocnti omna ayn bde i su sliesdte idnaesit htheerninosnu-lcaotiomnb cuostmibpleo noer ncto imn ab unsutmiblbee to 40 pcf. Lightweight insulating concrete is further differen- roof assemblies. Whether built up,c r of solutions that ar e healthy for people, communities, and the planet.solutions that are healthy for people, communities, and the planet.tiated from structural concrete in that lightweight insulatingroof assemblies. Whether built up,UoLnCs tarundct iFoanc atonrdyiMs ulistuteadlraoso ft haes sinesmublaliteiosn.component in a number of single ply, modified bitumen orcPlasti-Fab helps create lasting communities by supplying Expanded Polystyrene (EPS) products to construction and civil Plasti-Fab helps create lasting communities by supplying Expanded Polystyrene (EPS) products to construction and civil eate lasting communities by supplying Expanded Polystyrene (EPS) products to construction and civil Plasti-Fab helps cr ULC and Factory Mutual roof assemblies. Plasti-Fab helps create lasting communities by supplying Expanded Polystyrene (EPS) products to construction and civil concrete is nonstructural, meaning it has limited structuralsingle ply, modified bitumen or oofing systems,With manufacturing facilities in Kitchener and Ajax, and a Winnipeg standing seam r e leading the industry with infrastructure projects. As the only vertically-integrated EPS company in North America, we ar e leading the industry with infrastructure projects. As the only vertically-integrated EPS company in North America, we arPlasti-Fab helps create lasting communities by supplying Expanded Polystyrene (EPS) products to construction and civil e leading the industry with infrastructure projects. As the only vertically-integrated EPS company in North America, we arPlasti-Fab helps cr standing seam roofing systems,facility delivering to Thunder Bay and Northwester TMplastifab.com HelpiHnegl pcirnega tcer elastingate lasting communities. communities. load-carrying capabilities. Lightweight insulating concrete typi- we can meet design and deliveryWith manufacturing facilities in Kitchener and Ajax, and a WinnipegTM e leading the industry with plastifab.com n Ontario, we have infrastructure projects. As the only vertically-integrated EPS company in North America, we areate lasting communities by supplying Expanded Polystyrene (EPS) products to construction and civil solutions that are healthy for people, communities, and the planet.solutions that are projects. As the only vertically-integrated EPS company in North America, we are leading the industry with e healthy for people, communities, and the planet.infrastructursolutions that are healthy for people, communities, and the planet.infrastructur we can meet design and deliveryOntario covered. e leading the industry with cally is placed over a form deck or other structural roof decktimelines on projects of any scale.facility delivering to Thunder Bay and Northwestern Ontario, we have e projects. As the only vertically-integrated EPS company in North America, we arsolutions that are healthy for people, communities, and the planet.solutions that are healthy for people, communities, and the planet.timelines on projects of any scale.Ontario covered.type for support. solutions that are healthy for people, communities, and the planet.It is important to note lightweight insulating concrete roofplastifab.com Helping create lastingcommunities. TMplastifab.com He p ng create lasting communities. TMplastifab.com Hellpiing createlasting communities. TM decks are not experiencing the same moisture migration prob- plastifab.com Helping create lasting communities. TMPlasti-Fab helps create lasting communities by supplying Expanded Polystyrene (EPS) products to construction and civil lems as structural concrete roof decks. The roofing industry hasinfrastructure projects. As the only vertically-integrated EPS company in North America, we are leading the industry with plastifab.com plastifab.com Helping create lasting communities. TMPlasti-Fab helps create lasting communities by supplying Expanded Polystyrene (EPS) products to construction and civil long understood and addresses moisture release in lightweightHelping create lasting communities. TMinfrastructure projects. As the only vertically-integrated EPS company in North America, we are leading the industry with solutions that are healthy for people, communities, and the planet.insulatingconcreteroofdeckswithbottom-and/ortop-sidesolutions that are healthy for people, communities, and the planet.venting. Based on this, the following information should not be considered applicable to lightweight insulating concrete; it isplastifab.com Helping create lasting communities. TMintended to only apply to normal-weight and lightweight struc- plastifab.com Helping create lasting communities. TMtural concrete.ORN THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ONTARIO ROOFING NEWSISSUE 1 202211'