Issue link: http://digital.canadawide.com/i/292860
rolling green roofs that fit in with the surrounding landscape," says Alena Dawson, green infrastructure manager. Native perennials were used as much as possible to increase bio- diversity and attract pollinators. "The installation of the green roof was very challenging with many obstacles to over- come," says Dawson. "We had an unprecedented heat wave, difficult access to the roof and some very shaded areas, so plant selection was very important. The neighbour was so impressed by the new green roofs that we have since installed one on her roof as well." One benefit of a green roof is the absorption of water, which assists in the city's stormwater management. The Roofing Contractors Association of British Columbia ( RCABC) has seen market demand for green roofing increase as an option and in some areas, being mandated by municipalities making these roof styles a requirement. "Green Roofing Systems are not going to go away and this is something we support," says Ivan van Spronsen, executive VP. "It can be an excellent choice, but specifiers need to be aware at some point that they are creating something that can be at war with the roofing system. There are plants and root sys- tems that, if not managed correctly, can be invasive." He adds that it is important to have correct designs and thoughtful processes. Using proven technologies is the most prudent course of action. Green roofs tend to attract a lot of novel solutions to systems that may or may not have survived the test of time, or have a long track record of performance, says van Spronsen. "They may look good in another weather environment scenario, or perhaps in a lab, but does it have the actual experience to survive the climate in which it is subjected to? We are cautious in our embracing of the technologies because we want to make sure that they do indeed perform. There is potential to have difficulties that can be very challenging to retrofit after-the-fact." The BC Construction Association wrote a detailed report on green buildings and echoed the concerns of using unproven technology in the province's climate, adds van Spronsen. Stepping away from the vegetative green roof model, Tech-Crete Processors Limited from Salmon Arm, B.C., offers SRI panels that have been installed on institutional buildings, refineries and other large facili- ties. "All of our products fit into the green roof story in that their longevity has been proven," says Ryan Hunniford, operations manager. "We have been in the market for over 30 years and had panels on roofs for the same amount of time. In case studies, people have taken a roof that is 25 to 28 years old, had mem- brane failure, pulled the panels up, put a new membrane down and reused 80 per cent of the old panels." Hunniford says the panels qualify for LEED credits, especially for high-albedo roofs. "Being all white, they reflect the light producing lower heating and cooling costs. Aside from the solar reflectance, it's a PMR [Protected Membrane Roofing] system. This means all the insulation is above the membrane, which 3D rendering of the XF301 Xeroflor Sedum Standard system. This system is very versatile and components can be mixed and matched to achieve a variety of objectives, both esthetic and environmental. pushes the dew point up and away from the roof mak- ing it more durable resulting in a longer life. Our SRI [Solar Reflective Insulated] roof panels are rated by the Cool Roof Rating Council [CRRC]." Whether the choice for green roofs are natural or panel, the end result will be a beautiful city, wherever that may be. n 38/ april 2014 Green roof Systems p36-39Green Roof.indd 38 14-04-02 4:53 PM