Green roofs, building roofs that actually use living plants as the exposed surface, are very prevalent in Europe, but are just now catching on in the Untied States. Literally any building can be designed with a green roof. The advantages to a green roof are that it can reduce energy use by moderating temperature on the roof and surrounding areas. It also can dramatically reduce storm runoff volume and peak flow rate by holding and releasing stormwater slowly. A green roof can also restore the ecological and aesthetic value of urban open space by replacing a stark conventional roof with a green, softer roof line. Last, a green roof will protect conventional roofing systems, typically doubling the service life of the underlying waterproofing membrane.
As a matter of public policy PLNA recommends that any new public building be designed with an energy-saving, stormwater managing green roof.