You likely would not be surprised to hear that Facebook this year installed a 9-acre garden roof on its new office building. But, more than just another perk for Bay Area tech hipsters like in-office nap pods and on-site dry cleaning, so-called green or vegetated roofs have been around for decades and are growing in popularity. In fact, the U.S. General Services Administration (GSA) maintains more than 2 million square-feet of green roofs, with their oldest one—on the Robert F. Kennedy Department of Justice building in Washington, D.C.—dating to 1935.
North of the border, Toronto was the first North American city to require vegetated roofs for new developments, having passed its Green Roof Bylaw in 2009.