Green roof on Battle Creek's public safety building

Expansive green roof on the Ford Rouge Plant in Dearborn, Michigan

Green roofs are a strategy used to capture the stormwater runoff from commercial, industrial and residential buildings.  In contrast to traditional asphalt or metal roofing, green roofs absorb, store, and later evapotranspire initial precipitation, thereby acting as a stormwater management system and reducing overall peak flow discharge to a storm sewer system. Furthermore, conventional roofing can act as a source for numerous toxic pollutants including lead, zinc, pyrene, and chrysene.  Green Roofs not only allows for a more aesthetically pleasing feature but acts as a friend to the environment but slowly releasing clean water into storm drains.

 BENEFITS

• Green roofs offer benefits including reduction of urban heat island effects
• Increased thermal insulation and energy efficiency
• Increased acoustic insulation
• Increased durability
• Extending the life of a roof (2 to 3 times more than a conventional roof)
• Providing aesthetic improvments in urban areas
• Improved air quality
• Conserving valuable land that would otherwise be required for stormwater runoff controls

 URBAN HEAT ISLAND EFFECT  

An additional benefit to urban cities is the reduction of urban heat.  The buildings, concrete, asphalt, and the human and industrial activity of urban areas have caused cities to maintain higher temperatures than their surrounding countryside. This increased heat is known as an urban heat island. The air in an urban heat island can be as much as 20°F (11°C) higher than rural areas surrounding the city.

Europeans, led by the Germans, have been using green roofs for decades and have found them to be a cost effective method to mitigate some environmental impacts of development.

DID YOU KNOW...

One inch of rain on a 1,000 square-foot roof yields approximately 623 gallons of water!