Issue date: 10/30/07 Section: News

Media Credit: courtesy William Retzlaff Biology professor William Retzlaff's work as the research coordinator of the Green Roof Environmental Evaluation Network was featured on ABC's "Extreme Makeover Home Edition" Sunday.

Biology chair and professor William Retzlaff represented SIUE on Sunday's episode of ABC's "Extreme Makeover Home Edition."

Sunday's episode featured an Arizona family of six living in a trailer in the desert.

The Extreme Makeover team decided to build the family a green home, complete with solar panels, a wind turbine and a green roof. That is where Retzlaff comes in.

Retzlaff said by default he became the research coordinator of the Green Roof Environmental Evaluation Network ( G.R.E.E.N.) A green roof is a roof that is partially or completely covered with some sort of plant life and soil.

The G.R.E.E.N. group researches the benefits of green roofs on buildings. Retzlaff said there are four main benefits.

First, a green roof reduces storm water flow off of the roof. When it rains all of the water that falls on flat surfaces like parking lots and roofs has to go somewhere like a storm water system.

A green roof intercepts that water and reduces it. Retzlaff's data says that 50 percent or more of the rainfall that falls on the roof is retained and does not go into a storm system.

Second, is what Retzlaff calls the "heat island effect." He said the reason that downtown St. Louis is hotter than surrounding areas is because of all the concrete and black roofs that absorb ultraviolet light and radiate that heat during the day.

"In fact, in Chicago, the mayor has been told that if he greens 65 percent of the downtown area with green roofs he will lower the air temperature by 10 degrees in the summer time," Retzlaff said.

Third, Retzlaff said, green roofs reduce the energy cost to heat a building in the winter and cool it in the summer.

He said he has begun working with Ameren to build 27 scale model buildings on campus, some with and some without green roofs to evaluate the energy cost of heating and cooling the buildings.

Last, and most importantly, Retzlaff said that green roofs last much longer than regular roofs, which have to be replaced about every 20 years. Ultraviolet light and the heating and cooling of the building break down roofs. Green roofs in Germany have lasted almost 100 years.

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