Roofcorp has talked about new environmentally friendly types of roofing in the past like “cool roofs” which are usually white, and of course roofs with vegetation known as green roofs. Green roofs have been recently explored not only for their insulation value but their ability to reduce storm water overflow. A new type of roofing has been introduced to specifically target storm run off. Ladies and gentleman, meet the blue roof.
Blue roofs are being tested in large metropolitan areas with sewer systems that service both waste and roof run off. A blue roof uses water retention systems to temporarily hold back large amounts of rain to prevent sewer systems from being overrun with runoff while at the same time reducing the overall temperature of the surrounding environment.
The blue roof slowly releases the runoff back into the sewer system after the rain has passed and the sewer is better able to handle the extra material. This prevents excess sewage from backing up the system and running off into local streams, rivers and other natural habitats.
Geosyntec Consultants, along with environmental engineer firms Hazen and Sawyer and Hydroqual, water management group Biohabitats and the New York City Department of Environmental Protection (NYCDEP) have launched a pilot program of blue roofs across New York City.
The pilot program is installing different forms of blue roofing across the city to test which methods work in preventing this kind of overflow and is one of many different types of green related roofing materials that the city is testing out.
The testing includes several forms of water retention systems including dams, risers, retention ponds and ballasts. The most successful tool designed is what Geosyntec has designated the “Blue Roof Tray,” a tray supported with ballasts constructed to hold up 2 inches of water. These trays proved to retain up to 45% of the storm run off in testing. The materials are relatively easy to install because they can just sit on top of previously installed roofing membranes.
Testing and the utilization of blue roofing material is still ongoing as the NYCDEP continues to explore more options for environmentally conscious roofing materials.