The installation of vegetated roofs in North America increased by 30% between 2006 and '07, according to the third annual Green Roof Market Industry Survey. The Green Roofs for Healthy Cities nonprofit organization (www.greenroofs.org), which sponsors the yearly survey, reported that slightly more than 2.4 million sf of rooftop was planted during the past 12 months.
Chicago takes the top spot, having planted 517,633 sf of rooftop last year. The city has numerous policies and programs in support of green roofs, so vegetated roofs should continue to grow above the Windy City.
Coming in a distant second is Wilmington, Del., with 195,600 sf of green rooftops, followed by Baltimore (121,550 sf), Brooklyn, N.Y. (102,908 sf), Virginia Beach, Va. (100,500 sf), Royersford, Pa. (100,000 sf), Toronto (83,055 sf), and Calgary (61,720 sf).