France recently joined the trend of requiring all new commercial buildings to install at least a partial "green roof" covered with vegetation, solar panels or a combination of both. These green roofs, and green walls, offer a variety of environmental and recreational benefits that have the potential to significantly improve a community's landscape.
"There are a wide range of different types of green roofs," Steven Peck, founder and president of Green Roofs for Healthy Cities, said. "There are ones with parks, trees and shrubs, some that grow food, some that are designed specifically for biodiversity and some that are designed mainly for aesthetic purposes."
According to Peck, there is a long list of both public and private benefits that green roofs and green walls can offer to anyone that chooses to install them. Some of the public benefits include acting as a system of storm water management by retaining rainwater, as well as acting as an air filtration system by absorbing possible pollutants.
A major benefit of green roofs and walls that has been receiving a lot of international attention is their potential to provide increased energy-efficiency in heating and cooling. Energy management is a growing concern, and green roofs may be part of the solution.
According to a recent study, green roofs with high vegetation densities can be up to 60 percent more energy efficient than non-green roofs. This is because vegetation acts as insulation, so heat can be stored more efficiently in the winter, and cool air more efficiently in the summer. Also, shade provides a way to naturally cool air before it is pushed into a building, so less air conditioning is required.
Some other benefits of green roofs include providing stress relief during the work day, serving as a source of employment and local recreational activities and providing the option to grow local, sustainable food.
"There are a lot of public benefits to green roofs, so that is why we are seeing more and more jurisdictions invest in them," Peck said.
According to Peck, the places in North America that have been doing the most investing in green roof technology have been Washington, D.C., and Chicago in the United States, and Toronto in Canada. "Last year, D.C. was the number one jurisdiction for green roof installation in North America," Peck said. In Toronto there have recently been 241 installations of green roofs, for a total of over two million square feet.