San Francisco requires that certain new buildings be built with a green roof, the law require between 15 to 30 percent of roof space on most new construction projects to incorporate solar, green roofs, or a blend of both. Some of the city’s developers have supported the new green roof law, saying they are glad it offers an additional alternative to meet eco-friendly requirements.
The EPA estimates green roofs start at about $10 per square foot for simple projects, or up to $25 per square foot for more ambitious designs.
Green roof legislation is being passed around the world. Cordoba became the first city in Argentina to require green roofs in July. France’s new legislation mandates at least partial coverage of green roof or solar technology on all new construction and goes into effect next March. In 2009, Toronto mandated green roofs on industrial and residential buildings. Germany’s green roof industry has been legislated and supported by the government in various ways since the 1970s.
The Benefits of Green Roofs
Green roofs reduce stormwater runoff, improve air quality, and help mitigate the urban heat island effect. For building tenants and owners, green roofs reduce the need for heating and cooling. They also can provide food and a recreational area for residents.
Combining solar panels and green roofs can actually make each component work better. Solar panels can provide shade for plants and grasses, reducing the need for watering, while the panels work best when they are cool (green roofs can help lower temperatures compared to conventional ones).
More than ever, green roofs and green infrastructure is becoming an imperative. As climate change makes regions hotter and urban areas grow, cities with green roofs will get an array of benefits that will improve quality of life for their citizens. “The cities that invest in green infrastructure will be cities that thrive next century”.