b'TECHNICAL & RESEARCHmembrane is suggested. When specifying taperedproducts.insulation, elevations should be checked using theCopings can make a big impact on a buildings maximum thickness used in the system.aesthetics, but design professionals must Low-set clerestory windows can provide pleasingremember that they are not waterproof. sightlines, and mechanical, electrical and HVACWaterproofing comes from the roofing membrane engineers may have solid reasons for wanting wallinstalled over the parapet wall. Shop-fabricated penetrations in certain places. These elevations must,copings must be fastened on both the outside and however, also account for the specified thickness of theinside of the wall, and these penetrations of the roofing system. Failure to do so may cause the roofingmembrane are leaks waiting to happen. Instead, system manufacturer to not approve the warranty. Moredesign professionals should protect the integrity of important, it will jeopardize the long-term performance ofthe membrane by specifying standard edge metal the roof and the building. or by choosing snap-lock-style copings.Roof Edge Design When covering exterior fascia, thicker metal should In a list of the most important considerations whenbe used to prevent oil-canning, or a perceived designing a low-slope roof, the roof edge comes inwaviness in the panel. The longer the span, the second, behind only roof slope. thicker the metal must be. That, of course, comes The majority of roof failures are the result of metalwith a higher price tag. A more cost-effective option edge failures in high-wind events. The Roofingfor longer spans is to use a combination of smaller Industry Committee on Weather Issues Inc.s 2007face metals24-gauge steel up to 8 inches longreport on wind-related roof damage caused byand fascia extenders.Hurricane Katrina backed this up, stating ManyConclusionexamples of damage appeared to originate atWhen it comes to delivering a high-performance, failed edge details. The report also offered thedurable and warranty-eligible low-slope roof, solution, saying The main lesson learned appearssuccess does indeed lie in the details. Sufficient to be that roofs designed and detailed accordingdrainage, protective edge metal and properly to current codes and standards will performflashed penetrations are all crucial. Getting those satisfactorily. details right starts during the design process. The Edge design is, therefore, not an area for cuttingtime and thought invested will be well-rewarded in corners or pinching pennies. fewer change orders, a higher-quality and faster Design professionals must not waver in requiringinstallation by the roofing contractor, and a happier that all edge metal products meet ANSI/SPRI/ building owner.FM 4435 ES-1 Wind Test Design Standard forJim Flickinger is the architectural specification Edge Systems Used with Low Slope Roofingtraining manager for low-slope roofing Systems standards, and should specify that all aremanufacturer Mule-Hide Products Co., assisting manufacturer-provided, pre-fabricated products.design professionals with roof specifications Roofing manufacturers system warranties excludeand details. A member of the American Institute edge metal that does not carry the certification.of Architects (AIA), the International Institute of If standard-compliant products are not used,Building Enclosure Consultants (IIBEC) and the the building owner will forgo that edge-to-edgeConstruction Specifications Institute (CSI), his protection, and if a blow-off occurs because thedecades of experience in inspection, training and edge metal fails, the roofing manufacturer willinstallation of multiple commercial roofing products not be responsible for repairing or replacing theallows him to share actual field conditions with membrane. specifiers and contractors.Continuous cleats, or clips, are required on faces with dimensions of 4 inches or greater, and the materials should be at least one standard gauge thicker than the exposed metal. This is the new standard, and all manufacturers offer such www.mrca.orgMidwest Roofer 17'