Issue link: http://digital.canadawide.com/i/124234
photos: Monika Mistry Growing Up and Coming of Age Green roofs are a practical part of an efficient building envelope by Godfrey Budd he popularity of green, vegetative roofs has been getting a boost lately as their benefits – like longer lasting membranes and stormwater control – have grown increasingly important to owners, designers and other construction sector stakeholders. A report last fall from Lux Research projected that the global market for what it termed building-integrated-vegetation, a category which includes green roofs and walls, would grow to $7.7 billion by 2017. It said that the lion's share of this, a whopping $7 billion, will be accounted for by green roofs alone. Although mature markets for green roofs in countries like Germany and Switzerland should expect slowing demand, North America and Asia will likely provide growth opportunities, said the Lux report. "The whole industry is expanding rapidly," says Matt Barmore, product manager for system enhancements at Firestone Building Products. "North America spent $300 million on green roofs in 2012." Unfortunately, the extra upfront costs could remain a barrier to green roof installations, despite the long-term benefits, according to Lux. But the report, as well as green roof specialists in Canada and the U.S., see environmental awareness in major cities as a driving factor behind growth. In one respect, Canada is playing a pivotal role in the world's green roof sector. As Barmore points out, Green Roofs for Healthy Cities is the sector's biggest industry association, globally, and is based in Toronto. The city promulgated a green roof program a few years ago, which is becoming something of a template for other cities. "Washington, D.C., is rewriting its code, based on Toronto," Barmore says. The Lux report says that cities across the developed world have announced mandates or incentives for green roofs. "In Montreal some boroughs are mandating a certain amount of greenery on new buildings," says Jean-Jacques Laplace, Quebec distributor for XeroFlor Canada Inc. XeroFlor's standard system, the XF 301, weighs just 12 pounds per square foot and can be used on roofs with up to a 30-degree pitch. Many new condo developments in Toronto have green roofs incorporated within their design, says Sasha Aguilera, operations manager at XeroFlor Canada Inc. She points to design standards as one of the areas of concern around green roofs. Wind resistance, potential fire hazards and the risk of root penetration are some of the others. The good news is that some systems – like XeroFlor's XF 301 – do, in fact, provide a certificate with installation. This tells the owner how much wind it can take and how high up it can go. " Green Roofs for Healthy Cities and the Single Ply Roofing Industry (SPRI), which represents sheet membrane and related component suppliers in the commercial T 13-03-06 3:37 PM Green Roofs p22-25GreenRoof.indd 23 roofing sector, have worked together on developing standards on wind, fire and root penetration. These standards have been approved by the American National Standards Institute (ANSI) and are expected to be adopted by the U.S. building code, Aguilera says. She adds that, "The National Research Council in Ottawa is doing some research on this." In the meantime, a good resource on standards and best practices is available in the Roofing Practices Manual (RPM) at the Roofing Contractors Association of British Columbia (RCABC) website. "Anyone can access this and request that everything is done to our standards. Following [the standards] provides a lot of protection for the roof membrane," says Rob Harris, the technical manager at RCABC . RPM methods and standards, he says, must be followed when a client has requested the RCABC Guarantee Program. Also, the RPM "is quite often specified as a standard to be referred to even if the contractor is not a member of the RCABC, just as a roof done to Factory Mutual standards is accepted throughout the insurance industry," he says. Harris warns that maintenance is also important. "The first two years of plant maintenance should be part of the installation contract. After two years, the plants are 90 per cent established. Pre-grown mats, or trays, are ways to reduce the problem, as with these mats or trays you have established plants [prior to installation]," adds Stephen Toronto-Dominion Centre's green roof by Flynn Canada Ltd., Toronto, ON. Teal, a green roof specialist with the Calgary office of Flynn Canada Ltd. The use of vegetative mats or trays, and hardy, low-maintenance plants like sedums, are popular ways to keep green roofs relatively simple to maintain, says Jasmine Vesque, communications and marketing manager at Nedlaw Living Roofs Ltd. This plant versatility is resulting in a new trend in the green roof market called "urban agriculture." The intent is that roofs are used to grow fruit and vegetables, explains Jelle Vonk, account manager at ZinCo Canada Inc. The new ZinCo Urban Rooftop Farming system encourages this growth by providing a soil that is compound-rich with minerals and other nutrients. "It won't be long before growers will be enjoying the fruits of their labour – literally in the city," says Vonk. Flynn Canada has recently done major green roof projects in Toronto, Edmonton and Calgary. The Calgary and Edmonton projects involved new, green roofs for existing buildings – respectively, a city hall and a federal building. But perhaps the biggest such project on the continent is the new green roof for april 2013 /23 13-04-05 1:58 PM