b'SOLAR REFLECTIVITY Figure 2 (LEFT): AERL building, southeast side (RCABC).Figure 3 (RIGHT): AERL southeast roof area, looking south. Note repair patches in the area between the two visible drains (RCABC). a narrow upper roof supporting venti- cut test samples and project construc- membrane temperatures were the cause lation hoods for the office spaces below,tion documentation, we wondered if theof blistering and premature membrane a wider lower-level roof at the northwestcurtainwallglazingmightbereflectingfatigue, will the problem be mitigated by side of the building (the roof supportsenough solar heat to grow the blisters andoverlayingthemembranewithpavers nearlyallthemechanicalequipmentdestroy adhesion between the membraneorgravel?Furthermore,willdifferent servicing the building), and a southeastplies. The building orientation suggestedmembrane colours change the outcome roof on the same lower level that doesthat reflected solar radiation (includingtoo?Andfinally,howdowetestour not have equipment and is narrow. AllUVradiation)wasapossibleculprit.suspicions and study possible solutions?threeroofswereconstructedwithaThis led us to initiate a study with UBC, compact 2-ply SBS-modified membraneusing the AERL roof as our subject to roof assembly over a concrete deck. explore our hypothesis that the reflectedThe ProjectThesoutheastroofabutsafull- solar radiation was leading to the blisterToanswerourquestionsandtestour length,double-glazedcurtainwallproblemonthesoutheastroof.Withhypothesis, RCABC engaged the services (clerestory) assembly. Each glazed unitthat came further questions: if reflectedofStructureMonitoringTechnologies is approximately 1200 mm (48) widesolarradiationandconsequentialhigh(SMT)andMorrisonHershfield and is separated from the next by an anodizedaluminummullion.Blisters occurred randomly adjacent the curtain wallassemblyonthelowersoutheastCOMMERCIAL,CANADASroof and extended into the roof field1by as much as 2700 mm (9) from the#glazing. The blistering phenomenon wasINDUSTRIALNational Interior Protection unique to the southeast roof. Cut tests showed debonding of materials inside& NATIONWIDEspecialist for the past 15 yearsand around blisters, but no discernable moisture between plies or in the insula-tion assembly. wheremembraneblistersSERVICES!Strangely, had been repaired over the previous two years, blisters reoccurred. By all appear-ances the roof system seemed unstable. Nothing in the roof installation reports indicated any obvious design or installa-tion issues (Figure 3).The situation was perplexing. After1-877-365-1915 www.interiortarpprotection.caanextensivereviewofphotographs, www.rcabc.org l23'