Green roofs

City of Toronto

City Council approved a Green Roofs strategy [PDF] promoting the use of city rooftops to grow gardens and other vegetation. The strategy includes a commitment to install green roofs on new and existing buildings owned by the City whenever practical. Council also endorsed initiatives to provide financial incentives for the creation of green roofs. Follow the Green Roof strategy's progression from consultation to adoption.

Benefits of a green roof - Study Findings

• reducing stormwater runoff that affects water for drinking and swimming, as well as habitat in local rivers and lakes
• reducing energy consumption
• reduces the urban heat island effect by lowering the City's temperature and reduce cooling costs
• beautifying the City
• creating more natural green spaces in urban areas
• providing more opportunity for food production
• Reduction in stormwater flow of 12 million m3 per year
• Infrastructure savings worth $79 million
• Erosion control measures savings worth $25 million
• Pollution control cost avoidance worth $13 million
• 3 additional "beach open" days per year worth $700,000
• Citywide (Toronto) savings from reduced energy for cooling is $22 million, equivalent to 4.15KWh/m2 per year
• Cost avoided due to reduced demand at peak times is $68 million
• Widespread greening of Toronto's roof would reduce local ambient temperature from 0.5 to 2 degrees Celsius
• Citywide savings from reduced energy for cooling of $12 million, equivalent to 2.37 kWh/m2 per year
• Cost avoided due to reduced demand at peak times of $80 million
• Reduction in levels of CO, NO2, O3, PM10, SO2
• Reduction in CO2emissions
• Potential for local food production
• Habitat for birds and invertebrates
• Energy savings from better solar reflectivity, evapotranspiration and insulation
• Green roofs last up to twice as long as regular roofs
• Green roofs can beautify and add value to Toronto's buildings by providing scenic views and recreational areas in dense urban areas