The Ottawa courthouse on Elgin Street will add grass and tundra plants to its roof next year as part of an initiative by the province to design more environmentally sustainable construction projects.
The courthouse, a prominent civic building in the downtown core, and the roof designed by the Ontario government will bring more than 6,782 square metres of green roof to Ottawa’s cityscape.
“Ottawa is one of the least progressive cities in the country,” says Dana Silk, general manager of Envirocentre, an organization that provides advice and services to Ottawa homes and businesses about energy efficiency.
“The green roof at the courthouse is a great idea. I think the province should be commended.”
The courthouse, built in the mid-1980s, has a conventional flat roof. The switch to a green roof began in 2009 when Infrastructure Ontario brought in an architect to design a custom-tailored roofing solution. The project is expected to be completed in 2012.
“Both the building’s roof and the exterior grounds were scheduled for repair and replacement,” says Jeff Giffen, communications advisor at Infrastructure Ontario.
“This presented a perfect opportunity to consider a unique and environmentally conscious roof replacement option,” he says.
Ottawa was ranked as the worst of Canada’s five largest cities for green infrastructure in a survey conducted last winter by magazine Corporate Knights.
The courthouse is an ideal location. The flat roof can support considerable weight, says Silk. Green roofs are heavy; they consist of several layers of soil and waterproofing material, and vegetation planted on top.
Tundra plants are usually chosen for their ability to survive Canada’s extreme temperatures.
The new roof will do more than just beautify the courthouse. Green roofs reduce air conditioning needs, as they insulate their buildings. Most urban roofs reflect heat back into the atmosphere to create a heat island effect, but the plants on a green roof absorb radiation, cooling down and cleansing the air.
The roof will also absorb rainwater that usually flows off roofs into sewers. The sewers can then overflow into the river and kill aquatic life, says Silk. This makes a green roof a much more cost-effective alternative to the pricey underground storage tanks the city bought to hold this water, says Silk.
These roofs are just one small step and not many other green initiatives are in place, says Silk. While the new roof will hopefully inspire change for other flat-roofed buildings in Ottawa, it would have been nice to see similar efforts made during the construction of city hall or the new convention centre, he adds.