Metal Roof Edges Part 2 - Reasons to Specify Pre-Manufactured Roof Edges

Metal roof edges are key to the performance of a low-slope roof. In an extreme weather event with high winds, the edge of a low-slope roof is very important. Factory Mutual, a leading building insurance company, attributes 80% or more of all roof failures directly to failure of the roof edge.

Shop-fabricated edge metal has been used in the industry for years, but before the adoption of the ANSI/SPRI ES-1 standard by the International Building Code (IBC) there was no standard testing for wind resistance requirements. The profiles were developed over time as shapes and gauges that worked for various conditions and were generally created locally by the roofing contractor or a sheet metal shop. Quality and consistency can vary from fabricator to fabricator and locality to locality.

Pre-manufactured edge metal, on the other hand, is tested by third-party labs to rate their profiles for wind resistance, and in the factory, to maintain a level of quality and consistency. The products are available nationwide, at the same quality and consistency level.

Shop-fabricated edge metal may have exposed fasteners that can rust, leak, or prohibit thermal movement. Fasteners driven through the roof edge in the field may be spaced improperly and impede thermal movement.

Pre-manufactured edge metal can have snap-on details with no exposed fasteners and offers a clean look without leaks. Pre-punched slotted fastener holes assure proper fastener locations and allow for thermal movement.

Shop-fabricated edge metal has miters, end caps, and accessories which are field-fabricated, often yielding in a cobbled-together appearance. Curved sections are generally formed out of segmented straight lengths, riveted or seamed radius which can give a rough appearance.

Pre-manufactured edge metal manufacturers offer factory-fabricated and finished miters, end caps, and accessories which provide a clean, professional appearance. Radius sections are welded to fit the project's actual conditions providing a smooth, finished look.

Shop-fabricated edge metal offers little or no warranty protection from by the fabrication companies, which have varying and unknown levels of experience. Field-painted edge metal is often not properly prepared to assure good paint adhesion; also, many paints will not hold up to extreme UV exposure, which can result in fading and chalking over time.

Pre-manufactured edge metal includes, as part of the roofing system warranty, coverage up to 30 years and peak gust wind speed coverage up to 120 mph. Factory finishes that incorporate Kynar 500 or Hylar 5000 baked-on architectural paint to provide a finish that is warranted for up to 20 years.

For your next specification, choose the metal roof edge which suits your project, has the profile and accessories you need, and meets your performance needs.

For more information on metal roof edging, check out the Design References on the Carlisle SynTec website here.

Contact Craig Tyler at [email protected] with questions.