High above Calgary’s streets, patches of vibrant greenery continue to replace dull, gray rooftops. Plants sway in the breeze, absorbing rainwater, reducing heat, and providing a habitat for animals. These living rooftops aren’t just visually striking — they are a sustainable solution to some of the city’s environmental challenges.
As more Calgarians embrace green roofs, the benefits are becoming clear. But what exactly makes them so effective, and how do they contribute to a more sustainable future?
Green roofs are made of vegetation layers installed on conventional rooftops and effectively combat urban heat islands, improve air quality, and enhance biodiversity.
Green T Design is helping transform rooftops into thriving green spaces as green roofs become increasingly popular around the city.
Cost-effectiveness
Although they come with higher upfront costs than traditional roofing, their benefits extend beyond aesthetics.
“It costs more to build a green roof than just a conventional roof. But if you evaluate what that green roof is going to return, it’s going to contribute to staff retention because they can access that roof or they can see it from the window, and that gives them a little bit of a nature break in their day. And they’re tackling their stormwater management on-site through the use of that green roof,” said Kelly Ross, founder and principal of Green T Design.
The architectural design company is at the forefront of the green roof movement, working with businesses to incorporate green infrastructure into Calgary.
Calgary’s climate
According to a 2016 study, green roofs are most effective at retaining stormwater in drier climates, with Calgary achieving a 67 per cent retention rate compared to London, Ont. (48 per cent) and Halifax (34 per cent).
Extended dry periods in Calgary increase the capacity for water retention. According to a 2014 study, the city received 220.45 mm of rainfall over 46 events, yet only 16.3 mm drained away, meaning 92.6 percent of the rainfall was retained.
Benefits of green roofs
The study also emphasizes that integrating more green roofs in Calgary could provide multiple benefits, such as reducing urban flooding risks, enhancing building energy efficiency, boosting biodiversity, and improving air quality.
“Green roofs enhance the triple bottom line environmental, social, and economic benefits,” said Ross. “Stormwater management is one of the greatest benefits that they are recognized for, regardless of the size, they absorb rainwater, which will reduce the burden on our stormwater infrastructure systems.”
But those are not the only benefits of green roofs. They also benefit people too.
“Green roofs are beneficial for us people as well. It improves our habitat. They’re shown to improve mental health and well-being. Viewing nearby nature and green space reduces stress and promotes relaxation,” said Ross.
Challenges of green roofs
City officials are exploring policies to mandate green roof installation on new developments, following the example of cities like Toronto, which require green roof coverage for specific buildings.
According to a green roof report from 2014, while Calgary is gradually adopting green roofs, the challenges include a harsh climate, regulatory hurdles, and higher initial costs. Green roofs have also been an option for bonus density and increased floor area ratio (FAR) incentives in the city.
Calgary continues putting in green roofs as climate resilience becomes a top priority.
Green T Design remains committed to transforming rooftops into thriving green spaces.
Green roofs have “multiple benefits. Too often, many of them get overlooked because people look to single solutions,” said Ross.