Issue link: http://digital.canadawide.com/i/178290
Hastings Park Child Care Centre, Vancouver, B.C. Garden roof assembly: Detec Membrane Integrity Testing. Architect: PJ Lovick Architect Ltd. Photos: John Riley, InterCoast Building Solutions Inc. government, commercial and institutional projects, including one in Edmonton on the Williams Engineering Building. "The typical green roof would not survive well in Edmonton or Calgary. We developed a model using moisture retentive growing media and native plants that have survived. The system holds water and cools in summer," says Buist. Last summer, the irm completed work on the new Canadian Museum for Human Rights in Winnipeg. Living Architectural Systems, says Buist, has done some pioneering work on water retention. One of the irm's projects was a green roof for the Canadian War Museum in Ottawa. It has very high water retention and can handle 100-year rain events, he says. When modern green roofs were irst developed in Europe about 30 years, the focus was mostly on getting the plants to survive rooftop conditions, and not so much on issues like stormwater or cooling. Technologies and systems for green Green Roof Systems p.34-39Greenroofs.indd 37 roofs have evolved since then, and says Buist, clients should feel free to specify for performance. "Some actual specs are for more than one gallon [of water retention] per square foot," says Buist. He adds that parameters should also be set for percolation as well as retention. Performance standards might not be too far off. Buist says that several organizations are currently working on developing them. Clearly, costs related to stormwater management are an issue for cities across the continent – anywhere, perhaps, that the occasional downpour is an inconvenient fact of life. Spurred by heavy rainfall events like last August's Hurricane Irene and projected costs for stormwater upgrades running into the billions of dollars, several U.S. cities look set to deploy a range of solutions to mitigate stormwater run-off, according to a staff blog on the Natural Resources Defense Council's website. Philadelphia is a case in point. Last summer, the city's water department APRIL 2012 /37 3/26/12 2:22:54 PM