Green roofs reduce the amount of storm water run-off by 50%-90% and reduce the peak flow rate of run-off. During a 1″ rainfall, 100% water retention is achievable. Green roofs filter out 95% of the cadmium, copper, and lead and 30% of the nitrogen and phosphorous in storm water.
Heat Island Effect
Green roofs are instrumental is cooling the surrounding air and reduce the temperature of hot air that hovers over cities. On a 90 degree day, a black roof’s surface temperature is about 150 degrees, while a green roof’s temperature is only 90-95 degrees.
Green roofs typically have double the lifespan of standard roofs.
Green roofs reduce the energy required for heating and cooling. By insulating the upper floors of buildings, green roofs reduce the amount of heat required in a building.
Carbon Dioxide and Air Pollutant Reduction
The plants on a green roof convert atmospheric carbon dioxide. Green roofs filter airborne particles including those that cause respiratory diseases.
Sound Transmission and Reflection Reduction
Green roofs reduce the transmission of noise by 5 to 45 decibels and the reflected sound by up to 30 decibels
3 Examples of Green Roofs in New York City