It is a well known fact that the Washington, D.C. area has some of the worst storm water control problems in America. Compounding the impact of the problem, the District’s waterways flow to the Chesapeake Bay, endangering its $3 billion dollar a year seafood industry. Slowly but surely, the Federal Government and the District Government authorities have come to recognize greening the District’s rooftops as the most viable and economical means of addressing the storm water control issue.

The U.S. General Services Administration (GSA) describes the benefits of a planted roof as increasing insulation value, reducing storm water runoff, improving water quality, reducing urban heat island effect, conserving energy, reducing sound reflection, creating wildlife habitat, and improving the aesthetics of the typical roof. An often overlooked benefit and one with significant asset management impact is the prolonged life of the roof membrane, from 50 to 100 years. GSA’s oldest planted roof was installed in 1975.

The United States Tax Court, one of a number of notable General Services Administration’s greening projects, was reroofed in 2008 with a Barrett Company 4″ extensive “Greenroof-Roofscapes” assembly, adding to the growing federal green roof inventory within the Capitol District.

“MTFA Architecture led this 40,000-square-foot roof replacement project for a building designed by Victor Lundy and completed in 1974. It is recognized as a historically significant modern work, eligible for inclusion in the National Register of Historic Places.

To accommodate the historic nature of the building, existing structural design loads, sustainability concerns and preservation of the exterior appearance from the street level, MTFA Architecture used several different roofing types to achieve a sustainable, practical solution,” (MTFA Architecture).

The green roof initiative is reducing the storm water runoff volume while providing the many other environmental contributions that Greenroof-Roofscapes are known to provide including increased roofing longevity, carbon dioxide-oxygen exchange, reduced interior noise pollution and reduction of the urban heat-island effect. The project actually has two wings with three green roofs totaling 5,500 sf of vegetated area: two green roofs on the north wing and one on the south wing.

Two succulent plugs per sf were used including Sedum album; Sedum spurium ‘Fuldaglut’; Sedum kamtschaticum; Sedum sexangulare; Sedum reflexum ‘Blue Spruce’; Delosperma nubigenum, and Sedum rupestre ‘Angelina’. An erosion control mat was placed on top of the extensive growing media. A 6″ gravel strip was placed around the perimeter and 2′ pavers were used for maintenance walkways around the roof hatch and access ladders. Not publicly accessible, the U.S. Tax Court’s Greenroof-Roofscapes provides a visual delight to its high-rise neighbors.