Green Roofs are conventional rooftops that have a thin layer of vegetation designed to capture, temporarily store, and reduce stormwater runoff. While traditional roofing materials shed nearly all rainfall as runoff, a green roof is able to absorb and evapotranspire a portion of that rainfall.
There several variations of green roofs depending on building specs, limitations and goals. Green roofs offer additional benefits including the potential reduction of heating and cooling costs.