March 14, 2024
Toronto's green roof bylaw keeps on giving
Back in 2009, Toronto City Council, under the leadership of Mayor David Miller and Deputy Mayor Joe Pantalone, took a major step forward towards sustainable urban development. Toronto became the first major city in North America to adopt a Green Roof Bylaw. The Bylaw mandates green roofs on new buildings, provides an incentive program for existing buildings and creates a standard for the construction of all green roofs. The Bylaw was the result of over a decade of lobbying, research and education by Green Roofs for Healthy Cities, an industry group formed by Steven Peck, GRP, with a mission to develop the industry across North America. Similar policies have since been adopted by cities across North America, including Denver, San Francisco and New York. In Canada, Montreal and Gatineau have implemented a similar set of requirements.
The Green Roof Bylaw addresses environmental concerns associated with urbanization, such as the urban heat island effect, poor air quality, lack of accessible green space and biodiversity loss. The Green Roof Bylaw and the Eco-Roof Incentive Program align with the objectives of the City's climate action strategy, TransformTO, which aims to achieve netzero greenhouse gas emissions by the year 2040. By requiring and providing incentives for green roofs, Toronto sought to create a more sustainable and resilient urban environment. There are few, if any, public policies that can be implemented by local governments which deliver so many benefits for so little investment, and which provide ROI for building owners as well.
The Bylaw applies to new commercial, institutional and multi-unit residential developments with a gross floor area exceeding 2,000 square metres and new additions to existing structures if the gross floor area surpasses 2,000 square metres. The green roof coverage requirement is between 20-60 per cent of the available roof space. All agencies, boards and commissions of the City also have to implement green roofs on their new building projects.
Since 2009, the Toronto Green Roof bylaw and the Eco-Roof Incentive Program has been quietly greening Toronto's roofscape. The incentive program has resulted in the installation of 614 green roofs, contributing to the creation of 1.12 million square metres of green roof space. More than 1,000 green roofs have been constructed thus far, significantly reducing energy consumption by an estimated 2,200 megawatt-hours per year helping to avert 416 tonnes of greenhouse gas emissions annually. The green roofs have also diverted over 18 million litres of stormwater annually. In 2023 alone, 43 projects were successfully completed, resulting in an additional 78,000 square metres of green roof space. There are a tremendous number of benefits associated with the program, not the least of which are the employment opportunities for design professionals, contractors, manufacturers and maintenance personnel.
Many landscape architects, architects, engineers and developers have embraced green roofs not only to comply with regulations, but as a way to enhance the overall quality and value of buildings, such as by providing high quality amenity space for building occupants. Accessible and even only visually accessible green roofs have been shown to improve the real estate and rental value of properties and the health and wellbeing of those who have access to them.
Green roof technology continues to evolve, both in terms of the plants and growing media used to support biodiversity and food production, as well as integration for greater stormwater management benefits as in the case of blue-green roofs which provide additional stormwater retention and detention benefits.
To learn more about evolving green roof and wall technology, you’re invited to the 20th anniversary celebration of CitiesAlive, Nov. 6-9, 2024, in Toronto, Ont. The event will provide a unique opportunity for landscape architects and other designers to learn, connect, engage and leave with tools that will help them use their clients' roofs to future-proof their communities.
To learn more, visit citiesalive.org or greenroofs.org