Green Roofs

Green roofs use plants and soil to absorb and filter rainwater, insulate buildings, and provide habitat for birds. Montgomery County has green roofs on 13 facilities, including one property with four acres of green roof.


Green roofs (or living roofs) are covered with vegetation and a growing medium, planted over a waterproofing membrane. Green roofs absorb and filter rainwater, keeping streams and rivers clean. They insulate buildings and save energy. They also provide food and habitat for birds. They typically include a root barrier, a drainage layer, 3-4 inches of a soil mixture engineered for water absorption, and short plants that can withstand droughts and heavy rain.

Equipment Maintenance and Transit Operations Center

The green roof at the County’s Equipment Maintenance and Transit Operations Center in Gaithersburg is designed to provide a beautiful outdoor lunch or meeting area for employees, in addition to capturing and treating rain water for washing buses and flushing toilets. This roof is part of a four-acre complex of living roof across the 14 buildings that make up the transit center.

Gaithersburg Library

You can see the Green Roof at the Gaithersburg Library from the windows of the classrooms and offices on the second floor. You can get a glimpse of the solar panels, as well, making Gaithersburg Library a great place to see some of the County’s green technologies.

North Potomac Recreation Center

The North Potomac Recreation Center has several sections of green roof. This one includes a steel wire across the middle of the roof that maintenance crews use to hook onto their safety vests allowing them to weed and inspect the roof safely.

White Oak Community Recreation Center

The green roof at White Oak Community Recreation Center is one of several stormwater management techniques that help protect nearby Paint Branch. You can also see from this photo that portions of the roof that are not vegetated are white, which reflects sunlight and reduces the amount of energy needed to keep the building cool in the summer.