Issue link: http://digital.canadawide.com/i/1274063
J U LY 2 0 2 0 | 23 Green Roofs & Walls P H OTO G R A P H Y CO U RT E SY N E X T L E V EL S TO R M WAT ER M A N AG EM EN T T he popularity of green roofs and walls continues to gain traction around the globe, albeit a little more slowly here in Canada. One major advancement in the Great White North, however, is that while the market remains immature, more and more people are realizing the benefits of green roofs and walls that include significant social, economic, and environmental benefits, particularly in cities. In B.C., and in particular the City of Vancouver, uptake of green roofs is admittedly still slow-going compared with many other parts of the province and the country. James Klassen, technical advisor for the Roofing Contractors Association of British Columbia (RCABC), says the issue is more complex than just implement- ing a new policy: "Vancouver likes to think of itself as green, but we really aren't as green as other cities. The City of Vancouver is still working on developing policy in response to the motion that was passed by city council in 2018. The original motion was that it should fall under the Rain City Strategy, which is an integrated strategy to manage stormwater, but there are many different depart- ments who have a stake in this and they have to consider green roof limitations and the metrics they need to work with." To help advance the sector and build trust in green roofs, RCABC is in the process of developing a design and construction standard to support a green roof guarantee. "It would be a performance-based guarantee, just like our RoofStar guarantee. The idea is in the concept stage, and we're collaborating with Green Roofs for Healthy Cities to see how we can further the concept, but it is intended to respond to a disconnect between what I call 'intent' and 'results' that occurs. While there are numerous cities that have established green roofing policy or bylaws, there is no jurisdiction in North America that seems to have established a way to verify that the green roofs are designed and constructed in concert with those recommendations and guidelines, or a way to verify green roofs have been either been maintained by owners or will continue to perform." Dr Karen Liu, product manager for Bonar Xeroflor GmbH and partner with Next Level Stormwater Management team, says she is extremely excited about the cur- rent focus here in Canada on the stormwater management benefits of green roofs. Green roofs and walls provide an answer to some of our biggest urban challenges by NATALIE BRUCKNER Breathing New Life Into Buildings "People often talk about low impact development and source control, which is where the discussion of green roofs start as they can store and hold back the water at roof level making them a source control mechanism, preventing and delaying runoff from entering the stormwater infrastructure. Also, because cit- ies have limited space at ground level, green roofs are a great option as you don't have to dig up the ground." The Xeroflor green roof systems specialise in flexible pre-vegetated mats that can be easily transported, unrolled, and fitted, which is especially useful where landscape designs involve complicated shapes and contours. These thin lightweight mats are ideal for retrofits, or on older buildings unable to take heavy loads. This year, and looking ahead, Liu is excited that systems like Xeroflor are gaining more traction in North America, but says the green roof is still in its infancy here. "There's more urgency when it comes to green roofs in Europe and Asia because there is less space and they treasure the green space more. Here in North America we have a lot of green space, especially in Vancouver, so people don't yet see it as critical." Liu refers to Washington D.C., home to the most green roofs in North America, and adds "Washington is exemplary and even has a Stormwater Retention Credit Trading Program, where you generate and sell Stormwater Retention Credits to earn revenue for projects that reduce harmful stormwater runoff by installing green infrastructure or by removing impervious surfaces." Kees Govers, sales and marketing at LiveRoof Ontario, agrees with the other experts in the industry and says the two trends he is seeing when it comes to green roofs are stormwater management and biodiversity. "We are finally getting to a point where we are going beyond sedum," explains Govers. "While environmental awareness is indeed driving biodi- versity, an increasing number of developers are starting to see green roofs as a visual asset and looking at them as a way to make their buildings stand out." LiveRoof, which services a significant portion of the green roof market in Ontario with its innovative and horticulturally sound green roof systems, continues to be busy in all sectors with new and exciting projects. One of those projects is the Kipling GO bus station stormwater management roof project, which, once complete, will be more than one acre in size. "This is the largest project of its kind in Toronto. The entire green roof is raised 3.5 inches and has controlled flow drains that can cope with even the most severe storms," explains Govers. Other LiveRoof projects of note include: Algonguin College's 3,400-square- foot shaded biodiverse green roof; 80 Atlantic, the first new timber frame commercial building in Toronto; and Metrolinx's Eglinton LRT Maintenance The Xeroflor green roof system from Bonar Xeroflor GmbH.