b'Photo 2: A view of field-installed spray foam at a roof perimeter. The worker is using a long non-serrated blade in the reciprocating saw to trim the foam flusha laborious but necessary step.wall, use the butyl strip in the sameInsulation any of these insulation types willmost buildings is to mechanicallyboardjoints.Ideally,aperfect location to make a redundant com- Using larger-than-normal amountsperform satisfactorily. fasten the first layer of insulationinstallation would have no gaps pression seal. of roof system insulation in coldThere are two things to keepand adhere the remaining layersanywhere. Although this is ideal, Inadditiontotheairsealatinteriorenvironmentfacilitiesinmindwithinsulationonof insulation. it is not the reality of roof system membranelevel,usesprayfoamshould be expected. The decades- cold-storagefacilities.ThefirstThe second issue involves in- installation. A gap is not terminal in the metal deck flutes at exteriorold fight of R-value per inch of in- isdesign.Whendesigningforstallingtheinsulationandtheforacold-storageinteriorenvi-walls.Further,thegapbetweensulation against cost is not in de- energy usage and HVAC equip- inevitable gaps in the insulationronment facility, but an installer anyboardinsulationandcoverbate here. All forms of insulationment sizing, metal fasteners that boards at the outside wall shouldincludingpolyisocyanurate,pass through insulation can lead be foamed solid. Photos 2, 3 andextrudedpolystyrene,expandedtoenergylossasaddressedin 4showthefoamingandsealingpolystyrene and mineral wool ASTMInternationalsRoofing thatneedstohappenatoutsidehavebeenusedoncold-storageResearchandStandardsDevelop-walls. Figure 2 shows a CAD cross- facilities.Whenmanufactured,ment: 8th Volume and other stud-section of this air-stop detail. designedandinstalledcorrectly,ies. One way to minimize this inIdeally, a perfect installation would have no gaps anywhere. Although this is ideal, it is not the reality of roof system installation. A gap is not terminal for a cold-storage interior environment facility, but an installer needs to be mindful of these gaps.ORN THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ONTARIO ROOFING NEWSISSUE 4 2019/202011'