Manhattan’s first green roof, installed in 1998, sits on top of the 1902 Georgian townhouse at 122 East 38th Street in Murray Hill, the home of Earth Pledge, a New York based nonprofit that promotes green building technologies. Founded by Theodore Kheel to support the 1992 United Nations Earth Summit in Rio, Earth Pledge now sponsors the Greening Gotham program, an initiative to get New York City developers, building owners, and government officials behind green roof installation. Leslie Hoffman, Earth Pledge’s Executive Director, spoke with CityLand about the city’s standing, its policy and turning affordable housing green.

Why Green. Hoffman began as a minimum wage carpenter in Maine, became a general contractor and moved on to design green building projects. She holds a degree in Architecture and Design from Colorado College, has co-authored green technology books and even runs an organic coffee farm. Hoffman explained that green roofs are fundamentally lightweight, engineered systems of insulation, drainage, soil, and vegetation constructed on top of a traditional roof. It’s an “an elegant solution to common urban problems,” Hoffman declared, listing green roofs’ ability to boost insulation, cool buildings, reduce energy use by 10 to 30 percent, lower area air temperature, absorb 80 percent of storm water lessening runoff, and protect the roof from weather cycles and UV rays. Installation adds about $10 per square foot, but Hoffman points out that a green roof can last for 50 years where traditional roofs need replacement after only 15. The Greening Gotham program envisions a network of green roofs stretching across the city’s skyline, which advocates and researchers believe could diminish the “urban heat island effect,” a term used to describe the fact that the city is 3 to 6 degrees hotter on summer days than its surrounding suburbs. (read more…)