b'Steelroofdecksaremorecommonlyseenoncold-storagefacilitieswhereinduction-weldedthermoplastic single-plymembranesarepopularandhaveperformed well. However, beware of in-seam mechanically fastened systems. As presented in Condensation Risk of Mechani-callyAttachedRoofSystemsinCold-ClimateZonesPhoto 4: A view of a worker removing the release paper from a butyl strip on the from the 28th RCI (now International Institute of Build- exterior face of an insulated metal panel wall. This is the primary air seal. After the membrane is flopped over the wall, a heavy-gauge metal cleat will be fastened through this ing Enclosure Consultants) International Convention andbutyl strip. This will provide a compression seal as well as the cleat for the edge metal. Also visible is Trade Show proceedings, in-seam systems have a high pro- a white butyl-based sealant that was applied to the gap in the galvanized insulated metal panel wall cap.pensity to induce air movement that causes condensation issues. Therefore, in-seam mechanically fastened single-ply membrane roof systems are not a recommended choice on cold-storage facilities.Historically, ballasted roof systems have been a popular choice for cold-storage facilities. Currently, ballasted roof systems often are restricted by wind provisions in build-ing codes. Although a ballasted roof system still is a pos-sibility for cold-storage facilities, caution is advised as the loose-laid insulation in a ballasted roof system can lead to large gaps from long-term movement of the unrestrained insulation. As previously discussed, large gaps generally are problematic for air movement.Reroofing and RemediationWorking on the roof of a nested building envelope typ-ically is not a major issue as the cold environment and its special envelope are inside the building. Reroofing, modi-fying and repairing the roof system are possible without additional precautions.However, when reroofing or making an in-depth reme-diation of a roof system over a cold roof deck, condensa-tion problems can occur.If the cold-storage facility is still active, an exposed roof deck will quickly condensate and/or frost. Unless you operate in northern climates and are working during wintertime, the interior temperature most likely is at or well below the dew point or even freezing point. Work should be delayed until the outdoor temperatures are suitable enough for the metal deck to be above the dew point of outside air conditions. The materials available and speed at which the roofing crew can work are limited at these temperatures. But if the interior cool-ing system will not be turned off, these are the reroofing and remediation conditions in which a roofing contractor needs to work.Given these difficulties in reroofing or even repairing a roof over a cold-storage building, the owners of these facilities need to be well-versed in the conditions of their roof systems and the timelines for reroofing when the roof is part of a cold-storage envelope.Dont Get Caught in the ColdDesigning, selecting and installing materials for roof sys-temsoncold-storagefacilitiescanbesuccessfullyaccom-plished with proper research, detailing and quality control. Air flow within the building envelope of cold-storage facilities is critical and must be controlled at roof penetrations, tempera-ture change boundaries and exterior walls. Following these rec-ommendations can dramatically improve the performance of cold-storage facility roof systems. Matt Dupuis, PhD, P.E., is a principal with SRI Consultants, `Middleton, Wis.Reprinted with permission from Professional Roofing magazine.ORN THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ONTARIO ROOFING NEWSISSUE 4 2019/202013'