Energy Manager

Toronto Green Roof By-Law passes

Toronto, ON — Toronto Council passed the City's mandatory Green Roof By-Law yesterday, May 26th, by a vote of 36-2. Savings in electricity consumption and greenhouse gases can be significant with a green roof, but at what cost?

May 27, 2009  By Robert Colman

The Green Roof By-Law applies to new construction. One of the purposes of the use of green roofs is to counter the urban heat island effect. The law would come into effect for new construction residential buildings over 2,000 square metres (and 20 metres high) on January 31, 2010. Industrial buildings will be subject to the by-law a year later and will require 10 per cent of the roof or 2,000 square metres, whichever is less, for sod and other eco-materials.

A provision has been provided that cash in-lieu of a green roof required under the Green Roof By-law can be directed to an Eco-Roof Incentive Program to be used to green roofs on existing buildings.

Toronto is now the only city in North America with a by-law that both requires green roofs and establishes the construction standards for them.

While this by-law can be seen as an opportunity, it also appears to be a narrow focus for a complicated issue. White roofs are an alternative that can also effectively offset heat gain in buildings. The additional costs of such construction may be a constraint on development as well.


That said, I hope this creates change in the built environment in the city. It’s a great opportunity to catch up to cities like Chicago, and perhaps become a leader in the area. But compared to the need for better infrastructure in the city and increasing the energy efficiency of existing building stock, it’s a minor issue.

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