The Green Roof Requirement of the City of Toronto
Few environmental achievements are as dramatic yet so elusive in Toronto like the city of adoption of green roofs. Although Victoria Park station’s green roof is just visible from nearby high-rise apartment buildings, many commuters are able at least to catch a glimpse of Eglinton West subway a huge elevated rooftop garden on their way to work. Yet these so-called green roofs are not the same as traditional roofing materials. What exactly makes Toronto’s roofs green?
The term “green roof” generally refers to roofs that have long-term retention of moisture. This moisture absorption occurs through a membrane, such as slate or tile. The membrane allows rain water to flow down the roof, collecting and re-sieving into the ground water supply. By using these roofs during periods when the weather is dry, architects can decrease the amount of rain water collected in the roofing system and therefore reduce the potential for damage to the roof itself. By using a combination of materials that have long retention of moisture, a sustainable living roof can be built that conserves resources while reducing maintenance and installation costs.
The second example of a sustainable living roof is the air-conditioning and heating systems in the building. These roofs may incorporate active insulation, such as fiberglass batten roofs, or non-active materials, such as asphalt shingles. However, an important distinction between these two types of roofs is the role of the sewers and the pipes. Since the sewer system is responsible for collecting storm water runoff and transporting it throughout the city, storm water is a significant source of pollution. By installing a water-efficient heating and air-conditioning system on top of a green roof, water pollution can be reduced considerably. This saves the city money on energy costs and the negative impact on the environment of runoff from the roof.
Other examples include concrete roofs and the urban heat island effect. Concrete roofs are expensive to install because of the specialized knowledge and labor required. This means they are usually used in buildings that already have the plumbing and wiring in place. By incorporating a more efficient and sustainable structure on top of an existing roof, the building occupants benefit not only from the increased energy efficiency but also from the reduction of the greenhouse gases caused by the increased fuel consumption.
Roofs constructed with a green roof, on the other hand, allow the natural climate to continue its cycle of warming and cooling, resulting in comfortable living conditions year-round. A number of cities in New York City for example have seen phenomenal success in turning ordinary buildings into green offices, shops, and residential spaces. These buildings feature roofs that are constructed of recyclable materials and reduce the amount of solid waste that ends up in the landfill. In addition, the city has made it a policy to purchase and recycle anything used in the construction of its buildings.
Another significant advantage to incorporating roofs into the design of an urban space is their ability to enhance energy savings. When compared to traditional housing, the building owner stands to save a great deal on utilities bills through the use of green roofs and high-efficiency windows and doors. Some New York apartments and buildings have undergone upgrades that have allowed them to double their energy savings from just ten years ago. In addition to energy savings, green space adds visual appeal to the property.
Toronto’s Eco-roof incentive program encourages developers to use roofs constructed with recyclable materials and which incorporate storm water design features. The program offers substantial financial incentives to developers who employ these and other environmentally responsible design elements in building projects. This initiative, which has helped to increase the development of eco-friendly and sustainable structures in Toronto, is part of the City of Toronto’s broader strategy to become a world leader in sustainable city building. The inclusion of eco-roof facilities in new developments has helped to ensure that the City of Toronto remains a leader in green design and environmental initiatives.
The design of roofs in Toronto has changed dramatically over the past couple of decades. The increase in the number of residential and commercial properties in the city has led to the increased use of numerous design styles and materials. A notable exception to this was the original development of the Gardiner Square neighbourhood in Toronto, which architect Frederick Law Olmsted sought to design a structure that combined the traditional look of English townhouses with the sloping roof of an earlier style of roof known as the townhouse. The result was an incredible development that incorporated the best aspects of both and yet provided an unusual configuration that made the most of the natural topography of the area. As well as the innovative use of roofs for energy conservation and as a green roof requirement, the innovative use of the gable was also a contributing factor to the success of this unique development.
