Green/Living Roof
A roof surface covered by a water-proofing membrane, a drainage plane, a water retention medium, and plantings of drought-resistant species. The benefits of a green roof include control of storm water runoff which can reduce urban water pollution; absorption of airborne toxins and an increase in oxygen in the air, and a reduction of surface temperature of the roof (heat island effect). They also can increase the lifespan of the roof system and provide building and noise insulation. Green roofs are most common in multifamily or other large urban buildings.