Issue link: http://digital.canadawide.com/i/124234
the Jacob K. Javits Convention Center in New York. The 292,000 square-foot green roof will likely be one of the five biggest on the continent and is being done by XeroFlor America. This is a maturing sector that is here to stay. "Our expertise in waterproofing fits in well with a green roof system," says Carl De Leon, national sales manager with the roofing business unit at Sika Sarnafil Canada. For all its green roofing projects, the company uses Electric Field Vector Mapping (EFVM). "The system can pinpoint a leak location within inches and can be incorporated within a green roof at a fairly nominal cost," De Leon says. Sika Sarnafil, and some other green roofing providers, like Hydrotech Membranes Corp., provide complete systems with all components – a distinct advantage when it comes to warranties. "We provide a single source warranty for the whole system, and all components," says Denis Gingras, sales manager at Hydrotech. In Montreal, the company has just completed a green roof for a planetarium, set to open this spring. Hydrotech systems have been installed recently on federal government buildings in Ottawa and at an office complex in downtown Calgary. Some would say perennial green roof issues like extra cost, standards and warranties are dwarfed by the growing menace of extreme weather events and the related stormwater abatement potential of green roofs. Older cities, inside or even just on the fringe of the hurricane belt, can face enormous costs – in the billions for some – on the necessary upgrades to their water management infrastructure in order to deal with the greater incidence of extreme weather events. Cities with built-up density and aging infrastructure can't easily install and integrate a wide-diameter collector pipe within their systems. Instead, green roofs, and, on the ground, more extensive areas of permeable paving, are effective, lessexpensive stormwater abatement measures, most experts agree. Philadelphia, an older city that has been hit by severe storms lately, is a case in point. In recent years, it has moved aggressively to deal with stormwater runoff via green roofs and other measures. "Green roofs in 2011 did exceed 2010 by quite a bit. My guess is that 2012 will improve on 2011, when all the numbers are in. A lot of indicators point to more green roofs. Growth has been strong in Alberta and Saskatchewan," says Carole Dobson, green roof adviser for Western Canada at Soprema Canada Inc. Manitoba is also seeing more green roof projects, but costs can be higher because of a lack of local suppliers and the distance that the soil has to be shipped. The key to green roofs' role in reducing stormwater management costs stems from their water-retention capabilities. "Green roofs can act like a sponge. Some can retain up to 98 per cent of the water, then release it slowly. Green roofs sidestep, or delay, the need for more infrastructure," says Dobson, an agronomist by education and training. Prairie weather patterns could also be spurring demand in the West, she suggests. "Green roofs can result in less energy needed to heat buildings. A green roof can reduce heating costs by up to 25 per cent. In warm climates, the benefits of their cooling effects can be even greater." Dobson sees the benefits of green roofs as existing on two levels. Firstly, in energy savings, better real estate values, better esthetics and quality of life for owners and residents. Secondly, is at the societal level and through stormwater management. But, she adds, "The benefits in some areas are less tangible, but no less real. The sight of a green roof can relax people, according to studies." Zinco Canada has a new Summer Meadow system that provides an efficient irrigaton unit that is integrated into the water retention drainage board. "With specifically designed wicking mat we can bring the retained water to the plants more quickly. We can grow lawn and wildflowers with less growing medium depth and use less water for irrigation," says Jelle Vonk, account manager for ZinCo Canada. The versatility of modern green roof systems and products is likely another factor that is driving demand. Firestone's SkyScape green roof system, Barmore notes, is very flexible and offers plenty of options and technologies to accommodate a wide range of requirements. In the case of Above: ZUNI Condos + Lofts' green roof, Nuns' Island, Montreal, QC. Photo courtesy Hydrotech Membrane Corporation. Below: Grand River Conservation Authority (GRCA) – Laurel Creek Nature Centre, Waterloo, ON. Photo courtesy Nedlaw Living Roofs. a SkyScape multi-layer system, for instance, the growing media can range in depth from two to more than 10 inches. On one project, where a 20,000square-foot green roof was being installed atop a four-storey library in Surrey, a network of interlocking trays was first installed empty, without the usual complement of growing media, let alone plants. "This way, it's easier to install the trays," says Enzo Saponaro, a representative for DIV7 Building Systems. In a unique innovation for the project, the growing medium was blown up onto the roof using a bark mulch blower truck. The range of products that can be used as adjuncts to green roofs no doubt assists with their allure by improving their setting. Although the insulated roof panels from Tech-Crete Processors Ltd. were not designed with green roofs in mind, they can be used as a surround for a green roof. Research is also being done today that, it is hoped, will help fine-tune tomorrow's green roof systems. Noting that stormwater control is emerging in some regions as the most compellingly practical basis for green roofs, Kees Govers, technical sales representative for LiveRoof Ontario Inc., points to research that is being done at the University of Western Ontario. Three test sites – Halifax, Calgary and London, Ontario – are being used to determine the optimal composition for green roofs. "This research will be used to generate computer models that will show what mix of plants, depth and growing media should be used for a particular building in a particular location," he says. This type of research makes a lot of sense in a world where a green roof, as Flynn Canada's business development specialist, Terry McGlade, says, "is a practical part of a sustainable, efficient building envelope." n Green Roofs p22-25GreenRoof.indd 25 13-04-05 1:58 PM