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AUGUST 2016 | 25 Metal Roofing/Cladding PHOTOGRAPHY COURTESY AL13; ENGINEERED ASSEMBLIES INC. Innovation is driving the metal roofing and cladding sector by GODFREY BUDD S ome of the advantages of metal roofing and cladding systems – lightness, recyclability, esthetic versatility, fire resistance and durability – have been generally recognized for decades. However, the stars could be lining up to not only favour the sector as a whole, but also perhaps to give an especially keen boost to the appeal of metal roofing systems. For one thing, climate change and the increased incidence of extreme weather align with a growing emphasis on environmental performance and durability to favour roofing systems that are robust and long-lasting. "The expected roof life of a metal roof is 40 years, considerably longer than the 23-year expectancy of asphalt and 20 years of a single-ply roof," according to a document by the Building Owners and Managers Association (BOMA) International. In fact, since this report was released, most metal roofing products now come with a 50-year product warranty. Also, the range of textures, colours and finishes has expanded rapidly in recent years. "It's making standing seam a more universal product. Now, with more wide- spread manufacturing capacity and better shipping logistics, this kind of product is becoming more readily available. It's typically based on either sheet or coil steel and aluminum. Removing the former barriers to availability helps, but the improve- ments in underlayments and finishes are also helping to drive growth," says Richard Ruppert, architectural services manager for Firestone Building Products. For many years, rosin paper was used for underlayment, but today, engineered woven or composite fabrics with specialized coatings are being selected for better moisture and air resistance. For the exterior surfaces of roofs, polyvinylidene fluoride (PVDF) technology and advances in the understanding of the chemistry of finishes are enabling man- ufacturers to provide more durable and stable colours. "PVDF technology makes finishes extremely stable and almost indestructible. Instead of 10 years, we can expect today's finishes to last 20, 30, and maybe 40 years or more. They've greatly improved in the last decade," Ruppert says. Other improvements also add to the allure – and convenience – of metal roofing. The traditional look of standing seam is now being combined with highly engineered, precision manufactured components. "The roof section becomes weathertight as a panel is snapped into place in combination with an applied strip of sealant between each panel. Firestone's UNA-CLAD UC-4 system achieves a traditional standing seam appearance with the simplicity of a pre-engineered, site-delivered solution and up to a 30-year warranty," Ruppert says. A range of pre-engineered shapes, including concave, convex and "S" curves, tapering and long panels are part of the package with systems like the Series 300 from Imetco. Also, an advantage of a single-sourced whole metal roof system is that warranty issues involving various suppliers are avoided, says Blair Davies, VP of Engineered Assemblies Inc. The system includes a one-piece concealed clip made of 16-gauge stainless or gal- vanized steel, which is designed to provide maximum structural integrity. It also elevates the panel three-eighths of an inch off the substrate to allow for air move- ment. The one-piece clip, isolated seam sealant, customized trim, flashing and sys- tem details are designed to work together to accommodate the natural expansion and contraction of metal that occurs when it is exposed to varying temperatures. Out On Top ACM architectural panel system from AL13. Series 300 metal roof system from Imetco available through Engineered Assemblies Inc.

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