Green roofs have a layer of plant material that absorbs water like a sponge. They capture water when it rains, slowly releasing it through evaporation and plant use. Green roofs can significantly reduce the amount of rain water that would otherwise run off an impervious roof surface. Green roofs can also help reduce building energy usage and noise levels while increasing the durability and lifespan of the roof compared to conventional roofs.
Green roofs are being increasingly used in urban areas where space constraints limit the use of other stormwater management practices.
Note: Structures must be able to support the loading of green roof materials under fully saturated conditions.
Information About Green Roofs
How Green Roofs Reduce Urban Heat Islands, U.S. EPA
Information and links on how green roofs can help reduce urban heat islands
The Benefits and Challenges of Green Roofs on Public and Commercial Buildings, A Report of the United States General Services Administration, 2011 (PDF) (152 pp, 9.5 MB, About PDF)
This report includes a literature review of 200 research studies, in-depth analysis of green roof benefits, an original cost-benefit analysis, discussion of challenges and best practices, and assessment of further research needs.
Green Roofs, Technical Preservation Services, National Park Service, US Department of the Interior EXIT
Historic buildings are great opportunities for sustainable development and are regularly being rehabilitated to incorporate green design features while still preserving their historic character. One way of increasing the sustainability and energy performance of a building is to install a green roof. Find background for applying green roof technology to historic buildings.