The green roof movement in Virginia is spreading. Plant-covered roofs are popping up in Richmond, Charlottesville, Norfolk and Northern Virginia, reports Carlos Santos for the Times-Dispatch. Virginia is hardly in the forefront of the international trend, but at least it’s taking part in it.
Green roofs seem to be a case where marketplace economics and environmental sensitivities dovetail nicely. Green roofs generally cost twice as much as conventional roofs to install: They require additional layers of root barrier, gravel, topsoil and, of course, the ground cover. But they do provide a financial payback. The roofs last twice as long, and they reduce roof temperatures as much as 40 degrees from the ambient air temperature, which eases the strain on air conditioners and cuts electric bills. As a side benefit, the roofs help insulate against outside noise.
The social benefits are significant, too. Green roofs don’t just mean cooler rooftops, they also help reduce the urban “heat island” effect. In effect, each green roof makes a tiny contribution to lower temperatures for everyone. Even more meaningful, the plants and topsoil help manage storm water run-off by absorbing thousands of gallons of rainwater. Water that filters through plants and soil tends to be cleaner than water that runs off normal roofs, down downspouts and across parking lots. Water filtered through green roofs also is cooler, with less disruptive impact on aquatic life in streams.
How can Virginia accelerate the building and retro-fitting of green roofs? I’m not a big believer in income tax credits — our tax code is riddled with too many holes as it is. But I do think that buildings with green roofs should receive some kind of credit on its water-sewer bill to reflect their beneficial impact on storm water drainage. Perhaps the General Assembly could pass enabling legislation that allows municipalities to extend such a credit.
(Photo credit: Richmond Times-Dispatch. Photo shows a lower-level roof top of the SunTrust Bank building in downtown Richmond.)