Well-designed, engineered and maintained green roofs provide multiple environmental, social, economic and aesthetic benefits. GSA, which currently maintains over 2 million square feet of green roofs, has a long history of constructing and maintaining successful green roofs, dating back to 1935. Information about GSA's green roofs can be found on the agency's Green Roof Tracker. More guidance and information about green roofs can be found on the SF Tool website.