Teresa Madaleno

Green roofs are not a new concept and it isn’t as if we haven’t mentioned the idea in previous blogs, but what is new is developing green roof laws.

According to newspaper reports, San Francisco is now the first U.S. city to require that certain new buildings be constructed with a green design technique that sows plants above the roofline. The new law goes into effect in January and stipulates that 15 to 30 percent of the roof space has to include green roofs, incorporate solar or involve a combination of the two.

San Francisco is taking this strong stance as green roofs take root in more communities around the world. City officials have said that the move is a good way to build on an earlier environmental bill passed by the city’s Board of Supervisors last spring. It called for new residential and commercial buildings 10 stories or shorter to install solar panels or a solar heating system, covering at least 15 percent of the roof.

Places like Syracuse, Port Coquitlam in British Columbia and Washington D.C. support green roofs. Some estimate there are over 20 cities around the world that are aggressively promoting green roofs.

As described in National Geographic articles, green roofs can help improve air quality, reduce storm water runoff, and can mitigate the urban heat island. An urban heat island is a city that is significantly warmer than its surrounding rural areas due to human activities.

Some environmental experts insist that combining solar panels and green roofs work much better. The solar panels provide shade for many plants and grasses, reducing the need for the use of water. The solar panels work well when they are cool, which can happen easily since green roofs can lower temperatures.

Back in 2013 the city of San Francisco felt it was lagging behind other cities in terms of green building initiatives so they put together a task force that conducted research on green roofing, developed green roof policy, produced a cost-benefit analysis and then created an implementation manual, complete with how to install and maintain green roofs in San Francisco’s particular climate.

It might be interesting to find out how city officials in your area feel about green roofs.