CENTER FOR URBAN ECOLOGY/ WASHINGTON, D.C. /About 52 percent of Washington is covered with impervious surfaces, such as streets, buildings and parking lots, which helped to inspire the Center for Urban Ecology to install a 7,000-square-foot (650-m2) extensive vegetated roof atop its headquarters. A modular green-roof system was chosen as the solution because of its design simplicity. The soil and plant media are pre-installed in 100 percent recycled plastic modules that then are placed on the roof. The roof will retain storm water; potentially improve insulation properties; prolong roof life; reduce ambient-air temperatures to mitigate the urban heat-island effect; minimize dust and particulate matter; and provide a habitat for birds, bees and butterflies.

PROJECT SUBMITTED BY WESTON BUILDING SOLUTIONS INC., WEST CHESTER, PA., WWW.GREENGRIDROOFS.COM