Toronto mandates green roofs

Toronto now requires up to 50% green roof coverage on multi-unit residential dwellings over six stories, schools, nonprofit  housing, and commercial and industrial buildings.

The city of Toronto late last month passed a new green roof by-law that consists of a green roof construction standard and a mandatory requirement for green roofs on all classes of new buildings. The by-law requires up to 50% green roof coverage on multi-unit residential dwellings over six stories, schools, nonprofit housing, and commercial and industrial buildings. Larger residential projects require greater green roof coverage, ranging anywhere from 20–50% of the roof area.

"The City of Toronto's leadership on all things green took another major step by making it obligatory to have green roofs for all types of new buildings," said Deputy Mayor Joe Pantalone, the primary champion of the new by-law. "This by-law is a major part of the solution to climate change, the creation of green jobs, and it represents a whole new mindset on how our cities approach the 20% or so of surface area that are roofs."

Chicago has the greatest number of installed green roofs, according to the Green Roofs for Healthy Cities' Annual Green Roof Industry Survey released last month. The mandatory by-law in Toronto may change that, resulting in approximately 50 to 75 new projects annually, according to GRHC president Steven W. Peck.

Toronto already requires green roofs on city-owned properties, has established a financial incentive of up to $5 per square foot for existing buildings, and is currently building a publicly accessible green roof on its city hall.

For more on the green roof by-law, visit: www.toronto.ca/building.