According to the Institute for Business and Home Safety (IBHS),roof cover damage continues to be the largest, most frequentsource of non-surge related failures related to hurricanes¹.In response, roof covering manufacturers have provided a multitudeof products that have demonstrated through independent testing tobe able to withstand design event forces. However, it is apparentin the wake of recent windstorm events that much is lost in translation between theidealized laboratory setting and an actual constructed roof. Thisarticle will provide a brief review of the current codes, design,and selection process. It will also present a number of commonconstruction-related defects that result in the loss of millions ofdollars annually.

The selection of the roof covering in a hurricane-prone regionwould likely start with the locally adopted building code. For mostof the U.S., the building code is likely a recent version of the InternationalBuilding Code² with local- and regionallyspecific, amendments. Some jurisdictions—Florida, for example—havespecific codes that apply. The purpose of the code is to set aminimum standard of construction and design for the purpose of lifesafety. It typically does not purport to address other aspects ofthe functionality of the roof that might include resistance towater infiltration, service life expectations, hail resistance, andother functions that the facility owner may also require. Anotherdistinction to make is that codes, especially those related tocommercial buildings, have become less prescriptive and moreperformance-based in the last few decades. The code dictates thedesign criteria but not the number of fasteners per squarefoot.

Performance-Based Guidelines
Once the basic life-safety design criteria is established, localmunicipalities and insurance requirements take the design processfurther, by requiring the selection of assembly that has shownthrough independent laboratory testing to have a particularresistance to applied wind loads. It is the manufacturer of thespecific assembly that undertakes to have it rated by third-partytesting. The tested and rated assembly is specific with respect tothe materials, attachment, and configuration. Any variation in,say, the type of fastener used, would constitute a differentassembly that would require its own rating. Therefore, uponselection of an assembly that is meant to meet building code, localmunicipality, and, in some cases, insurability requirements, itbecomes imperative to closely follow the manufacturer’srecommendations for the installation of the assembly.