An AECOM team designed a “green roof” for the Morgan Processing and Distribution Center in Midtown Manhattan, the largest such project in New York City. The seventh-floor rooftop has been transformed from a tar- and stone-covered no-man’s land into a 2.5-acre park-like urban retreat for the facility’s 3,000 employees, with benches, native grasses and trees, and a view of the skyline that includes the Empire State Building.

Begun as a maintenance initiative, AECOM was asked to assess the required scope to determine if the replacement of the entire roof was necessary, or if a partial replacement would suffice. Based on an extensive background and knowledge of the Morgan facility, particularly the roof structural loading capacity, the AECOM team proposed the “green roof” concept to the USPS. The Postal Service had already been implementing a broader environmental initiative, which includes hybrid vehicles, recycling efforts and architecture initiatives, and the agency concluded that the proposed Morgan green roof made strong economic sense.

First built in 1933 and designated an historical landmark in 1986, the 2,200,000-square-foot facility is one of the largest mail processing and distribution centers in the country. The roof structure was originally designed to serve as an extra mail-processing floor, able to support 200 pounds per square foot, and thus was easily able to support the added weight of a green roof.

Green roofs are noted for their ability to reduce a building’s energy load. The Morgan green roof will help the USPS meet its target of reducing the facility’s energy use 30 percent by 2015. During the summer months, contaminants in stormwater runoff emptying into city sewers will be reduced by 75 percent, and reduced by 35 percent during the winter. With AECOM, the Postal Service also is pursuing LEED certification for the project.

The project is also financially sound: with a life expectancy of 40 to 50 years, a green roof will last approximately twice as long as a conventional roof.