Award

16 | A PR IL 2019 Green Roofs & Walls PHOTOGRAPHY BY GREG VAN RIEL/COURTESY NEXT LEVEL STORMWATER MANAGEMENT "The product is highly versatile, can be combined with other sustainable technologies, and used on conventional or protected membrane roof assemblies," explains Cristina Senjug at Next Level Stormwater Management. The company has been working on some very exciting projects of late, including the award-winning Two Old Mill in Toronto, Ontario. The lush and varied green roof on the condo's amenity deck is a beautiful mix of extensive and intensive vegetated roof systems. The lightweight and soilless system is 30-millimetres thick and is comprised of loose-laid base layers and a pre-vegetated mat. The vegetated mat includes eight to 10 species of sedum and arrives mature with 85 percent foliar coverage. In addition, the intensive green spaces have up to 1,200-millimetres of engineered growing medium that supports various species of grasses, shrubs, deciduous evergreens, perennials, and vines. "Over 50 percent of the species selected for the project are native to the area," explains Senjug. The project meets Toronto Green Development Standard Tier II and was recognized with an Award of Excellence in 2018 due to its its varied land- scape and vibrant palette. The rooftops contain a balance of spaces for relaxation, entertaining, and cooking, all situated within a lush and varied green roof. Another noteworthy project for Next Level Stormwater Management is the award- winning Broadway Tech Centre in Vancouver, B.C. The LEED Platinum-certified campus features eight low-rise buildings, four of which are covered with a total of 10,000 square metres of lightweight soilless vegetated roof systems. "They have a combined water storage capacity of 460,000 litres, and every year the four green roofs absorb 10-million litres of rainfall that feeds the plants and evaporates back to the atmosphere – diverting it from our stormwater infrastructure," says Senjug. James Klassen, technical advisor for the Roofing Contractors Association of British Columbia (RCABC), says he has seen a number of changes over the past 12 months, the biggest in B.C. being the initiative taken by the City of Vancouver to make living roofs mandatory on most commercial and multi-family buildings. "Policy is forthcoming, and we anticipate its release by autumn, but what is driving this initiative is a rising problem with rainfall runoff, and overburdened storm sewers that will have to be dug up and replaced unless the load can be eased another way," says Klassen. "Green roofs provide one answer, perhaps among many, to the question of how to handle rainfall runoff." RCABC has been involved, albeit in a small way, with the City of Vancouver and policy development, but Klassen says what is more exciting is the work the Association is doing with industry partners to write and implement a comprehen- sive green roofing construction standard and parallel QA/QC program. "While still in its infancy, we want to develop a standard that combines the roof or water- proofing and the vegetated systems. We've begun conversations with various stakeholders who study, design, supply, or construct green roofs, in order to write the best possible set of standards, and we are confident we can bring something to the B.C. construction industry that will be unprecedented in Canada. We aim to raise the bar on excellence," he says. That's not to say that the sector doesn't still face great challenges. "From a design standpoint, green roofing needs to be given the respect it's due. It needs its own section within Division 07 of the specification, so that it is tied to roofing [water- proofing]. When it is bundled together with grade-level landscaping in Division 32 [Exterior Improvements], builders end up with landscapers on the roof who don't appreciate the finer points and vulnerability of the waterproofing system that is there to protect the entire building. A roof, regardless of how robust it may seem, is not a place for garden forks, shovels, or inexperienced labourers," he says. Two Old Mill, Toronto, ON.

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