Green-roof bylaw earns mixed reviews

Toronto’s new green-roof by-law has earned praise from environmentalists but concern from local developers who worry about the impact of the by-law on their bottom line.

The green-roof by-law, approved by Toronto City Council in May 2009 , has won kudos from environmental groups who claim green roofs are both economically and environmentally viable. Stephen Peck, president of Green Roofs for Healthy Cities, said he appreciates Toronto’s recognition of this eco-business.

“This industry has the potential to really deliver a lot of sustainable development benefits … and make use of the generally wasted space we have in our city,” Peck said.

The new by-law affects all new residential, institutional and commercial building permit applications after Jan. 31, 2010 and January, 2011 for all new industrial development. The by-law has also become compulsory on all new developments above 2,000-m of gross floor area.

A green roof, a system of vegetated area becoming an integral part of the building’s roof, consists of a medium to grow the vegetation, a drainage system, a root resistant layer and a waterproof membrane to prevent leaks into the building.

In 2004, Ryerson University conducted a study that showed a temperature reduction of 2 degrees Celsius during the summer if only eight per cent of Toronto’s city roofs were converted to green roofs.

“It’s like air-conditioning for the outdoors,” Peck said.

According to the Ryerson study, green roofs also assist with storm water reduction. During a rainstorm, water streams across surfaces such as parking lots, sidewalks and driveways and then directly into Toronto’s overloaded storm-water system that feeds directly into local rivers and streams. In the process, the runoff picks up pollutants which contaminate the water.

“We’re using our natural water bodies essentially as an open sewer… and that is a multi-billion dollar problem,” Peck said.

Green roofs control storm water runoff by using materials on the roof that retain water. The study indicates other additional benefits include reduction in energy consumption and better quality of local water. As well, by having vegetation on the roof of building, more green spaces are created.

The study also that green roofs enhance air quality by removing carbon dioxide and monoxide from the air, resulting in estimated savings of $2.5 million for this city.

But since last year, many developers expressed hesitation about the extent of the by-law. Steven Daniels, a senior planner at Tridel, a residential development company, views the new by-law as costly and that the green roof by-law will cause repercussions with Toronto development.

“It will limit the number of new industrial buildings starts in the city of Toronto. The added costs will drive industrial investors [and] businesses to the 905 where it is cheaper to build and property tax is less,” Daniels said.

Daniels also expressed that Tridel faces some difficulty in attempting to meet the new requirements of the by-law.

“It will be challenging to implement these roofs, but we will be able to meet those challenges,” Daniels said.

However, Peck disagrees with Daniels’ assessment of Toronto development. He thinks that because the by-law applies to all developments in Toronto, it will not hinder developers who want to build in the city.

“It is [green roof by-law] applied equally to all new developments in the city. There are no competitive disadvantages associated with the requirement of green roofs,” Peck said.