Green Roof Bylaw

view of CN Tower from a greenroof

Toronto is the first City in North America to have a bylaw to require and govern the construction of green roofs on new development. It was adopted by Toronto City Council in May 2009, under the authority of Section 108 of the City of Toronto Act.

The Bylaw applies to new building permit applications for residential, commercial and institutional development made after January 31, 2010 and will apply to new industrial development as of April 30, 2012.





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Am I required to build a green roof?
The Bylaw requires green roofs on new commercial, institutional and residential development with a minimum Gross Floor Area of 2,000m2 as of January 31, 2010. Starting April 30, 2012, the Bylaw will require compliance with the Bylaw for new industrial development. Use the green roof screening form as a tool to determine quickly whether you will be required to build a green roof. Details of the requirements are provided below. The green roof coverage requirement is graduated, depending on the size of the building. The table below shows how the requirement ranges from 20-60 per cent of Available Roof Space for commercial, institutional and residential development. Available Roof Space is defined as the total roof area minus areas designated for renewable energy, private terraces and residential outdoor amenity space (to a maximum of 2m2/unit). A tower roof on a building with a floor plate less than 750m2 is also excluded from available roof space.

Gross Floor Area *
(Size of Building)
Coverage of Available Roof Space
(Size of Green Roof)
2,000 - 4,999 m2 20%
5,000-9,999 m2 30%
10,000-14,999 m2 40%
15,000-19,999 m2 50%
20,000 m2 or greater 60%

* Note: Residential buildings less than 6 storeys or 20m in height are exempt from being required to have a green roof.

What is the requirement for an Industrial building?
The Green Roof Bylaw applies to new building permit applications for industrial buildings or additions to industrial buildings where the Gross Floor area is 2,000 m2 or greater and the application was made on or after April 30, 2012. Under the Green Roof Bylaw, Industrial buildings are required to provide one of the following:

  1. a Green Roof covering the lesser of 10 per cent of Available Roof Space or 2,000 m2; or
  2. a roof that uses Cool Roofing Materials for 100% of the Available Roof Space and complies with the stormwater management performance measures required through the Site Plan Approval process. Where the Site Plan Approval is not required, the first 5 mm from each rainfall or 50% of annual rainfall volume falling on the roof is retained or collected for re-use at least through systems that incorporate roof surfaces.


Can I get an exemption?
For all development where a green roof is required under the Bylaw, the applicant may apply for a Variance or an Exemption where the requirement is not met. A Variance allows a smaller amount of green roof than is required under the Bylaw, provided that a cash-in-lieu payment of $200/m2 is made for the reduced green roof area, and the application is approved by the Chief Planner. An Exemption from the green roof requirement is necessary when a green roof is not proposed for a development. An Exemption requires the approval of the Chief Planner and a cash-in-lieu payment of $200/m2 if the application is approved. Contact the Community Planner assigned to your application for further details on the Green Roof Bylaw Variance or Exemption process.

I am required to build a green roof. What do I need to know?
To determine quickly whether you will be required to build a green roof and the size of green roof that must be provided, use the Green Roof Screening Form as a tool.

For new development requiring Site Plan Approval, green roof statistics should be provided with the Site Plan application to facilitate compliance with the Green Roof Bylaw at the time of Building Permit Application. Complete the template for the Green Roof Statistics and copy it onto the Roof Plan submitted as part of any Site Plan Control application or Building Permit application. For associated Building Permit Applications, complete the Green Roof Declaration Form.

For new development requiring a Building Permit only complete the required Green Roof Declaration Form for submission at the time of Building Permit Application.

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