Why green roofs haven't taken root in Saskatchewan

Nearly 7,000 square feet of succulents and native grasses sheath the College of Law building roof at the University of Saskatchewan. The drought-tolerant, low-maintenance species were selected for their ability to survive harsh prairie winters.

Planted in 2007, the green roof was seen as an improvement that would help the building achieve Leadership in Energy and Environmental Design (LEED) gold certification. It would also help insulate the roof, make it last longer, and reduce stormwater runoff.

Despite these benefits on top of being an effective tool overall to mitigate the impacts of climate change green roofs haven't caught on in Saskatchewan.

Michael Molaro is an accredited Green Roof Professional, who was involved in the College of Law roof and has one on his own home north of Saskatoon. He estimates there are only about 20 green roofs in the province. He attributes that low number to a few factors, including lack of awareness.

"Green roofs, for the most part, aren't accessible. People aren't able to experience them."

He adds that green roof professionals often aren't involved early enough in the building design process the extra load of a green roof needs to be planned.

Municipal governments also haven't prioritized green roofs through mandates or incentives, says Molaro. None of Saskatchewan's three biggest cities have green roof mandates or rebates in place.

Providing incentives

In 2009, Toronto became the first city in North America to pass a bylaw requiring the construction of green roofs on new buildings with a footprint over 2,000 square metres. The city's incentive program offers $100 per square metre of vegetation for residential and commercial buildings.

To put this incentive into perspective, if Molaro's home was built in Toronto, he'd be eligible for about $11,000 in rebates, which is about half the cost of his roof.

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High above Torontos busy city streets, green roofs are providing space and food, while helping to reduce flooding.

Today, Toronto has over 10 million square feet of green roofs, says Steven Peck, president and founder of Green Roofs for Healthy Cities.

"This isn't pilot project stuff at this point," he says. "Cities are putting in millions of square feet of green roofs every year to fight climate change impacts."

He adds that cities like Chicago and Portland use mandates and financial incentives "because they know that green roofs are going to deliver public benefits over the course of 15 to 25 years and beyond."

Those benefits, in many cases, can be measured quantitatively, like stormwater management.

"It's like a mini stormwater retention system, on someone else's property," says Peck.

That's something Saskatoon could benefit from in particular. On June 20, 2022, some parts of the city were inundated by upwards of 60 millimetres of rain in under two hours. Several neighbourhoods flooded.

Our cities have a lot of impervious surfaces, including roofs. When it rains, "the water is diverted quickly into the storm drains, and if they exceed capacity, you get potential overflow into the sewer system, which can cause a lot of problems," says Markus Brinkmann, director of the University of Saskatchewan's Toxicology Centre.

Non-irrigated green roofs have the ability to retain an average of 70 per cent of rainfall, according to a 2017 study by the University of Toronto.

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They also reduce the urban heat island effect, says Peck, which happens in cities laden with asphalt and concrete. In the summer, cities can experience temperatures 12 degrees warmer than the surrounding countryside, "and that's a problem," says Peck, "because now we're being hit with these heatwaves and heat domes that we never had before."

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When traditional roofs are replaced with vegetation, Peck says, "those plants and the growing medium will cool the building itself, saving energy, but also the surrounding area. It's like an outdoor air conditioning unit."

Green roofs also provide a higher level of insulation than a typical roof, meaning you'll use less energy and money on cooling and heating. A National Research Council of Canada study demonstrated that green roofs can reduce heat flow through a roof by more than 75 per cent in the spring and summer.

They also offer an opportunity for urban agriculture, says Molaro, and are a boon for pollinators. The U of S College of Agriculture, for instance, grows veggies on its roof.

A chicken-and-egg scenario

Green roofs' low uptake in some jurisdictions is a bit of a chicken-and-egg scenario. Costs for green roofs are high because there are a lack of local suppliers for soil substrate, plants and other roofing materials.

But it's hard to attract local suppliers if there's no market for green roofs. As Green Roofs for Healthy Cities explained in their 2023 policy guide: "Incentives encourage markets, but regulations establish markets, and provide predictable demand so that private sector suppliers can ramp up their activities."

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In 2013, Saskatoon's environmental advisory committee recommended a green roof pilot project. One of the main reasons was to help to reduce the impact of heavy rainfalls.

The committee said if the pilot worked out, the city could institute a bylaw that would require green roofs on all commercial buildings over a certain size.

The pilot never went ahead, and no one from the City of Saskatoon could explain why. The city now provides a stormwater credit for commercial buildings with green roofs.

In the city's June 2022 Pathways for an Integrated Green Network 10-year implementation plan, green roofs are one element that will be reviewed between 2028 and 2029, and are then slated for development in 2030-2031.

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Aside from rebates, cities can incentivize green roofs through zoning bylaws. Seattle and Chicago offer density bonuses, which allow developers to add extra floor space or additional storeys if a green roof is installed. Port Coquitlam, B.C., will fast-track development applications from builders who install a green roof.

'Just at our fingertips'

When Saskatoon resident Molly Seaton-Fast was planning a new garage last year, she reached out to Molaro to discuss adding a green roof. She and her partner were also considering solar panels and incorporating a garage suite.

"Ideally, we'd be able to do it all," she says. "They'd all be quite complementary and have their own benefits."

Solar panels are covered under the federally-funded Canada Greener Homes Grant; green roofs are not. So, the latter is off the table for now. She and her partner are still weighing their options.

Seaton-Fast would love to see any level of government take the initiative to offer green roof incentives.

"More local expertise would be nice," she says industry professionals with "more of a mind to what the future holds and how we should be building for it."

"There are so many creative ideas. I feel like they're just at our fingertips but also so far away for a number of reasons."