June 21, 2004 - Greenroof at 1425 K Street Shows the Way for Widespread Adoption and Community Benefits

Is Washington’s K Street finally going green? Long regarded as home to well-connected lobbyists and power brokers, the District’s K Street-area is not particularly known for environmental innovation. But two environmental groups and a long-established commercial real estate company today joined city officials including DC Council members Carol Schwartz and Phil Mendelson and a large group of sponsors, contractors, and property managers to unveil a new project to showcase the viability and benefits of rooftops planted with pollution-reducing vegetation in the heart of DC ’s business district.

A collaboration of DC Greenworks, Casey Trees, and Blake Real Estate, the 3,500 sq. ft. greenroof located 13 storeys above 1425 K Street is a showcase to accelerate the adoption of greenroof technology in the nation’s Capital. There are several greenroofs in and around the District, and many elaborate ones in other cities, but none here combine the size and elevation, or have been designed for the visibility and monitoring as this one.

Monitoring equipment to be installed next month on the greenroof, and on an unplanted control area, is expected to document a significant reduction in storm water runoff and rooftop temperatures. Water quality will also be monitored and if the European experience holds true, the roof will twice at least twice as long as conventional roofs. The reduction of storm water runoff in the city and across the region is a top priority for improving water quality in area-rivers and the Chesapeake Bay. Reduced temperatures mean less air pollution in a region suffering from unhealthy air much of the summer.

DC Greenworks is the technical lead and general contractor for installation and trained a workforce team of young adults from Covenant House Washington, a nonprofit youth services agency serving at-risk youth. Casey Trees is co-organizer of the project and a tenant in the building owned and managed by Blake Real Estate. The two also organized volunteers to help with planting and Casey Trees is coordinating outreach and will provide volunteers for monitoring and maintenance.

The project is supported by grants from the Chesapeake Bay Small Watershed Grants Program administered by the National Fish and Wildlife Foundation, and by the Watershed Protection Division of the DC Department of Health. Training for Covenant House youth was supported by the US Environmental Protection Agency and Bridges to Friendship.

Meteorologist Bob Ryan’s 4-Winds Program at WRC-TV is contributing to the cost of monitoring equipment and will be able to report live conditions from the roof. Commercial Roofing and Sheet Metal, Cheverly, MD, provided discounts for work to prepare the roof for the installation. Discounts or contributions were also provided by International Leak Detection and by Barrett Roofs, J-Drain Greenroof Drainage Systems, Laurel Valley Soils, and Emory Knoll Farms/Greenroof Plants.

Several steps were required to prepare the roof for 33,000 pounds of engineered soil and 9,730 low-growing succulent plants comprised of 11 species, of sedums. Following removal of the upper layers of the previous roof, a new waterproof membrane/root barrier was installed in conjunction with an electronic leak detection system that showed the system to be waterproof prior to planting. On top of the new membrane a two-inch layer of polystyrene insulation was replaced, topped by a layer of geo-textile filter fabric, and an inch-thick drainage mat. Soil was spread three inches deep across the roof and topped with a loosely woven jute mat to hold it in place until the plants are fully established in one to two years. The plants were hand planted in clusters to form a mosaic of variety, color, and texture. After planting was completed, the fully planted roof was again tested for leaks and passed with flying colors.

In the most heavily developed and paved areas in the city with few spaces for planting trees, greenroofs offer a practical alternative to reduce storm water runoff, temperatures, and air and water pollution. A study by DC Greenworks of a 255-acre downtown area (north of the White House to M Street and from 11th to 21st Streets) identified 86 acres of plantable roof area, fully 40 percent of all impervious surfaces in the area.

Transforming that much surface area from a major source of storm water runoff into greenroofs that capture (then evaporate or transpire) the first half inch of rain from most storms, could reduce runoff from this part of town by as much as 56 percent. Such a reduction would significantly reduce the initial surge of storm water that triggers the release of untreated sewage into area-rivers during combined sewer overflow events. By reducing air temperatures – a contributing factor to ozone formation – greenroofs, like trees, can help the District and surrounding jurisdictions meet federal air quality standards.

In coming months, tours will be offered by appointment on the second Tuesday of each month at 9:00 a.m. and on the last Thursday of each month at 4:00 p.m. Phone Blake Real Estate for reservations at 202/842-0771.

Media Contacts: DC Greenworks – Dawn Gifford, 202/518-6195. Casey Trees -- Dan Smith, 202/833-4010 x114 or Barbara Deutsch, 202/833-4010 x102. Blake Real Estate, Inc. – Joan Berman, 202/778-0400.

A detailed project description as contained in our proposal is available as a PDF download. (14Mb)