2010 REGIONAL GREEN ROOF INITIATIVE PROGRAM
The Districts interest in green roofs is in capturing rainwater on our regions rooftops and keeping that water out of our regional sewer system. This will help to reduce polluted stormwater runoff and
combined and separated sewer overflows to Lake Michigan. The 2010 Regional Green Roof Initiative Program will also provide significant environmental benefits to:
Significantly Lower Energy Costs: During the summer months, traditional rooftop
temperatures can be more than double the ambient temperature. Green roofs provide significant
insulation insulation that keeps summertime warm air out of buildings and cool air in (and
vice versa in the winter). One manufacturer of modular green roof systems, for instance, claims
to reduce heating and cooling costs from 25% to 50% for the floor directly below the roof.
Reduced Urban Heat Island Effect: Temperature increases of 5 F or greater are sometimes
found in cities where rooftops absorb energy in the daytime and emit that energy at night. Green
roofs can reduce this phenomenon, further lowering building energy costs in the summer.
Extended Roof Life: Green roofs protect traditional roofs from ultraviolet radiation that would
otherwise shorten their lifespan. Roof lifespans of nearly double have been documented in
countries with a longer history of green roof use, significantly reducing lifecycle costs.
