b'RESILIENCYNRC research is validating the use ofplatformtowhichpanelclipscanbebut if a conventionally insulated system underlaymentsasanecessarycompo- securely fastened. Also, pay attention tois your choice or best option, consider nent for resisting wind (the Building Coderidges and hips, widen valleys to managecoveringitwithavegetatedsystem does not require them but only imposes require- ahighersnowvolume,andconsiderorconcretepavers.Whilepaversand ments when they are specified). It is becomingspecifyinganddetailingwiderflashingvegetationwillprovideimpactprotec-clear that, insofar as wind resistance isfor broader coverage, paying attention totion and shield the membrane from the concerned,howtheunderlaymentisthe potential for snow drift. Finally, care- deleterious effects of reflected light and secured can have a significant impact onfullythinkthroughpenetrationflash- heat, a vegetated system will also shield its performance. For enhanced surviv- ingskeeping penetrations nearer thethe membrane from temperature swings, abilityinwindyconditions,stapleshighest point of the roof, or clusteringand it may coincidentally keep the entire should be avoided, and so should stan- them in a curb, can avoid damage frombuilding cooler in the warm seasons and dard shingle nails. Specify only big topsliding snow. warmer in the cool seasons.nails,andusenailswithametalcap, Sometimes,despitethedesign-not plastic. 10 BRACE FOR IMPACT ersbesteffortstoimplementprotec-Shingles themselves require positiveThere is an aphorism circulating in sometion strategies, the primary covering is tabbing to be effective in windy condi- social media circles that if you plan forcompromisedduringastorm(think tions. Dusty site conditions or compro- failure, youre failing to plan. Its catchy,falling tree branches). A resilient design mised packaging can contribute to thebutitonlyworksinaworldwherewillcontemplatethispossibility.It contamination of adhesive strips on thethere are no variables and everything isneed not be complicated. For example, bottom face of shingles. Some of this iscontrolled. In the rest of the world, vari- water-shedding roofs may be designed beyond the control of the installer, butables are abundant, and weather happenswithawell-secured,heavierunderlay-not all of it. When installation occursto be perhaps the most dynamic of themment;insomecases,afullyadhered duringseasonaltemperaturesoflessall. No one who designs a building canunderlayment may be desirable and will than 10 C, or the sealing strips will notcontrolwhathappenstoitonceitisoffersuperiorprotectionfromwater. readily bond to shingles below, specifybuilt, but it is possible to design a roof toWheremembraneroofsareconcerns, hand tabbing at a minimum until NRCreduce the chances of damage inflictedsmaller,self-containedroofareasmay research sheds more light on this issue. byextremeweatherandtolimittheservetolimitbuildingexposureto Slopeisasignificantconsiderationconsequences if damage occurs. water ingress or may simply reduce the foranywater-sheddingroof,butitFirst,rememberthatroofingmate- extenttowhichsystemmaterialsare becomesmoreimportantinextremerials are generally vulnerable to impact.compromised. A robust air barrier in a winter conditions. A resilient design willUnfortunately, there is little that can bemembrane roof system may also provide decidedlyincorporatesteeperslopes.donetoprotectwater-sheddingroofgreatsecondaryprotectionfortheAlso,considerheavier-gaugesteelforcoverings. You have more options whenbuildings interior.architectural metal panel roofs designeddesigningamembraneroofsystem.Aside from damage, any roof is espe-for locations with known heavy snow- Considerselectingmembraneswithacially vulnerable at the details. Few roof falls, and if the roof is insulated abovehigherpublishedpunctureresistanceleaks occur in the fieldmost happen thedeck,considershiftingthedesignvalue, or better yet, consider protectingwheretherearepenetrations,curbs, towardacoldroofdesignthiswilltheroofmembrane.Amembraneissleepers or where the roof intersects a keeptheinsulationassemblyseparatefully protected when the roof is prop- wall. A resilient roof design will incor-from the panels and utilize a sturdy, soliderly designed as a protected roof system,poratedetailsthatareproperlysepa-28 lROOFINGBClSPRING 2023'