TectaGreen, Green Roof Applicators

The Environmental Protection Agency defines an urban heat island (UHI) as a metropolitan area which is significantly warmer than its surroundings. On hot summer days, urban air can be 2-10°F [2-6°C] hotter than the surrounding countryside. Green roofs can work to reduce urban heat islands, minimize heat-absorbing surfaces, provide improved air quality, as wellhelp with storm water retention and filtration.

Green Roofs can be designed for exceptional storm water retention capability. The plants capture and hold rainwater. Water stored in the growing media is released through

evaporation and evapo-transpiration. Storm water retention rates are determined by saturated infiltration capacity, thickness of the growing media, field capacity, porosity, under-drainage layer water retention and flow, and relief drain spacing. Where jurisdictions demand lot-level storm water charges, zero runoff policies, or a requirement for storm water management ponds, this ability to retain storm water may result in direct and indirect financial incentives.

Green Roofs also filter out fine, airborne particulate matter as the air passes over the plants. Airborne particulates tend to get trapped in the surface areas of the greenery. Rains wash it into the growing medium below. Plants also absorb gaseous pollutants through photosynthesis and sequester them in their leaves. Studies show that tree-lined urban streets have 10 - 15% fewer dust particles than found than similar streets without trees.

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