Residential green roofs sprouting up

Credit: Green Roofs for Healthy Cities

Residential green roofs, also called garden roofs, may only represent a small percentage of the total U.S.residential market, but the industry saw triple-digit growth in 2011.

“The green roof industry grew by 115 percent in 2011, up significantly from 2010,” says Steven W. Peck, president of Green Roofs for Healthy Cities.

The top metro market for residential green roofs installed in 2011 was Washington, D.C., with more than 800,000 square feet installed. Chicago has installed more residential green roofs over the last decade than any other metro area, with more than 5 million square feet of green roofs installed since 2004. The survey showed that significant gains were seen in commercial, multi-unit residential, industrial and single-family residential markets as well.

About residential green roofs

Green Roofs for Healthy Cities, the industry association, describes a green roof system as “an extension of the existing roof that requires high quality waterproofing and a root repellent system, a drainage system, filter cloth, a lightweight growing medium and plants.”

The green roof systems can be modular, with drainage layers, filter cloth, growing media and plants already prepared in movable, often interlocking grids, or roofs that are built-up, adding each component of the system separately. This green space could be below, at or above grade, but in all cases the plants are not planted in the “ground’.

“Green roof technologies not only provide the owners of buildings with a proven return on investment, but also represent opportunities for significant social, economic and environmental benefits, particularly in cities. says Peck.