PEOPLE: contractor and installer, Houck Services Inc., Harrisburg, Pa.

GREEN POINTS: Completed in August 2007, this extensive 4-inch (102-mm) vegetated roof spans approximately 1,400 square feet (130 m2). System components include a concrete roof deck, tapered polyisocyanurate insulation, a cover board and 90-mil EPDM waterproofing membrane. The polypropylene non-woven needle-punched fabric is stabilized to resist soil chemicals, mildew and insects. At 0.4-inches (10-mm) thick with a water flow rate of 140 to 145 gallons per minute per square foot, the drainage board is designed to retain water in the vegetated roof while allowing the excess to drain. Three to 4 inches (76 to 102 mm) of growth media was used with three varieties of sedum. A 2-foot- (0.6-m-) wide bed of river rock around the roof’s perimeter prevents the system from drying out and a buried irrigation system uses only 0.7 gpm (0.04 liter per second) of water for the entire roof.

PROJECT PROVIDED BY CARLISLE SYNTEC / CARLISLE, PA. / WWW.CARLISLE-SYNTEC.COM