A couple of times per month, Julie Barnes climbs on top of her detached garage to check on her green roof.
Barnes and her husband installed it after they finished building their Saskatoon home in 2014.
“That’s when I started seeing green roofs on TV shows and in magazines,” Barnes said.
“We kind of wanted to offset the fact that we had added a lot of impermeable surfaces — we really wanted to minimize the runoff.”
After an online search, Barnes hired Higher Groundwork Horticulture owner and green roof consultant Michael Molaro and started planning.
It took five people three hours to manually plant more than 700 plants — all drought-resistant.
“The first year — just to get it established — we had to put a sprinkler up there and water it from time to time if there wasn’t much rain,” Barnes explained.
Besides that, she said the maintenance on the roughly 550 square-foot garden is minimal.
On top of aesthetic appeal, Molaro said there are a number of environmental and economic benefits.
“Green roofs will capture — depending on their design — at least 50 per cent of all the rainfall that falls on them over a season,” Molaro said.
“The vegetated roof cools the building in the heat and helps insulate it in the winter.”
He says green roof projects like Barnes’ can extend the life-cycle of the roof itself — from 15 or 20 years to almost 50.
“We have a proven track record now,” he said.
Like a green roof, the rooftop garden at the University of Saskatchewan (U of S) serves a similar function. Rain is intercepted using above-ground containers, but there’s the added value of food production.
“Utilizing land that wasn’t being utilized before,” said Grant Wood, an assistant professor in the U of S department of plant sciences.
“This was a bare, vacant piece of concrete and now it’s just teeming with food.”
He said the idea of growing things on a rooftop is a non-traditional practice and Saskatchewan is “catching up to the rest of the world in using this.”
The garden on campus is going on year five. Wood said using the space reduces “food miles” — the distance food travels from production to consumption.
“Ours isn’t food miles — ours is food feet,” Wood explained. “Less than 2,000 feet from production to consumption.”
However, you need to do your homework. When it comes to residential projects a vegetated roof can be more difficult to implement after the home has been built.
For Barnes, the initial investment was pricey despite doing a lot of the work themselves, and the project needs an engineer’s approval in order to get a permit.
Prairie weather is also a big factor.
“The challenges in the Prairies are the ‘plant pallet’ we call it — it’s very restricted to our weather conditions,” Molaro said.
“You want something that will survive our winters in a very shallow soil substrate.”
To Molaro’s knowledge, there are only about a dozen green roof projects in Saskatchewan. He cites a lack of awareness and experience with the industry as reasons for the slow uptake but is optimistic the numbers will grow.
“I’ve got high hopes to see it take off,” he said. He noted he’s been talking with the City of Saskatoon about its green infrastructure plan.
“We’ll be pursuing some pilot projects,” he added.
As for Barnes, she’s noticed much less runoff since installing the green roof and dozens of bees like to hang out up there. She hopes more pop up in Saskatoon.
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