Small components, big effects

Edge-metal systems are small—but important—parts of successful roof systems

Although various new products and installation methods constantly are being introduced to the roofing industry, one important theme has been consistent during the years—how products and components are assembled and installed are key to their performances. Edge-metal systems are particularly important to roof system performance, and it is crucial you know how to properly install edge metal at two of the most common locations in low-slope roofing: parapets and perimeter edges.

Mitigating failures

Roofing professionals know small components of a roof system can cause big problems during the system's life cycle if not properly addressed during design and installation. Although edge-metal systems are small parts of roof systems in overall proportion, they are a roof system's first line of defense against wind. If a roof edge comes off, the integrity and watertightness of the roofing and insulation materials may be compromised.

The Roofing Industry Committee on Weather Issues (RICOWI) noted in its September 2007 report about Hurricane Katrina that nearly 95 percent of roof system failures resulting from the storm were caused by poor workmanship or substituted materials. (Editor's note: NRCA does not necessarily agree with RICOWI's findings. For more information about NRCA's findings, see "Hurricane Katrina: observations from the field," December 2005 issue, page 22.)