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AUGUST 2017 | 23 Metal Roofing/Cladding PHOTOGRAPHY COURTESY MARINE ROOFING GROUP OF COMPANIES Metal roofing and cladding are becoming increasingly popular with architects across Canada by ROBIN BRUNET I t has been calculated that metal roofs and cladding can save up to 40 percent in building cooling energy costs and are an excellent base to support systems such as photovoltaic installations, due to their durability. These and many other benefits make them ideal for commercial, industrial and institutional projects. In fact, the use of metal roofs has grown to a point where they are now employed in almost 50 percent of new construction in these types of projects. When it comes to roofs in particular, metal can be a double-edged sword: on the one hand, more architects are using it for its ability to convey design ideas; on the other, failure to meet regional building codes or improper installation easily miti- gates the material's proven performance attributes. And as any experienced roofer will attest, commercial and industrial roofs are generally low slope systems (the slope being equal to or less that 3:12, or 25 percent) that require extreme care and skill during installation in order to be trouble-free. Hamish Matheson, RoofStar technical advisor for the Roofing Contractors Association of British Columbia (RCABC), says, "The devil's in the details, and the main difference with institutional and commercial buildings with metal roofs com- pared to residential is obviously the scale of things. Longer panel lengths require expansion and contraction calculations to be done. Certain materials have limita- tions, and on larger projects this is very important. Certain standing seam profiles and clip designs are not well suited for long run panels, for expansion and contrac- tion reasons. "Institutional and commercial metal roofs often play a heavy architectural fea- ture of the building and often very low slopes on these roofs are specified, which poses many challenges as metal roofs rely on a water shedding [hydrokinetic] principle rather than a waterproofing [hydrostatic] principle like low slope mem- brane roofs. Also, moisture control beneath the panel must also be considered such as condensation forming under the panels." Matheson goes on to note, "We as an association are dedicated to helping edu- cate and update the skills of installers wherever possible, and we recently took the opportunity to do so." The RCABC recently formed a subcommittee of industry experts and solicited input from engineers in New Zealand (where 70 percent of all roofs are metal, com- pared to only 30 percent in North America); the resulting flow of information is being used to overhaul the association's architectural sheet metal standards, which were first made available 16 years ago. "It's an elaborate process that requires an in-depth analysis of standards that work and those that don't, but we expect the entire overhaul – both written and detailed drawings – to be completed by early 2018," says Matheson. Meanwhile, the RCABC continues to be involved in projects that advance the popularity of metal roofs. Case in point: the University of British Columbia's new 6,500-square-foot Indian Residential School History and Dialogue Centre, built by Bird Construction during the particularly harsh fall and winter of 2016. The copper roof will age to a natural greenish hue with time and was designed with a simple, low slope in both directions that falls off to a waterfall feature on one side. "It has been a challenging project with copper being non-ferrous and posing significant expansion and contraction issues, but our collaboration with the Marine Roofing Group of Companies, which was responsible for the installation, has been a big suc- cess," says Matheson. Forms Of Expression Indian Residential School History and Dialogue Centre, UBC, Vancouver, B.C.

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