In the past, the only way to make a home 'green' was to paint the walls. These days, however, appliances, plumbing and lumber can all be green, as in environmentally friendly, and now you can add roofs to that list, as well.
In fact, so-called "green roofing"is on the rise, according to roofers like Grant Suelzle, vice president of URM Contracting Inc., a roofing company. In some cases, governmental agencies have made green roofing prescriptive for all nonresidential buildings, so demand is being fueled by regulation, he says.
Elsewhere, however, demand is being driven by cost and conscience; consumers want to save money, and they want to do something good for the planet while they're at it. Cool roofs, in particular-green roofs that use reflective materials to reduce buildings' energy demands-promise to help them do both.
Recognizing a shift in social perspectives, smart builders are changing both their posture and their products, according to Suelzle. "We personally gave up doing all hot asphalt roofing five years ago, " he says. "We've been doing solely green roofing ever since. "
When roofers turn their backs on traditional tar-and-gravel systems, Suelzle continues, customers, contractors and communities benefit.
Still, incentives are most pronounced for homeowners, according to Misha Sarkovich, program manager for the Sacramento Municipal Utility District, a public utility in the United States that began offering rebates for buildings with green roofing technology in 2001. Although some green roofing materials are pricey at the outset, Sarkovich observes, they tend to pay for themselves in long-term savings.
"You reduce air conditioning costs by having a cool roof," Sarkovich says, adding that homeowners enjoy an average of 20 percent savings. "A conventional flat roof on a hot summer day would have a surface temperature of 82 degrees Celcius; a cool roof on the very same building on the very same hot summer day would be about 54 degrees. By reducing the roofing temperature, you reduce air conditioning costs significantly. "
Green roofing has other advantages, too. Next to reduced energy bills, Sarkovich says cool roofs:
Although there are several types of green roofs, including vegetation roofs (on which tenants can grow gardens) and solar roofs that generate electricity, perhaps the 'hottest' roofs for green builders are 'cool' roofs, which are roofs built with light - colored materials that reject heat rather than retain it.
"Cool roofs have two properties: high reflectivity and high emissivity, "Sarkovich says. "Emissivity is a property of the material to emit energy so that it does not retain heat. Reflectivity is the ability to reflect solar energy back into the atmosphere. "
In roofing products, both reflectivity and emissivity are rated on a scale from 0 to 1; the higher the rating - and the lighter the color-the cooler the roof.
The best green roofing product for your project depends not only on the product's properties, however. It also depends on the slope of your roof. Consider, for instance, the following recommendations:
Whether you specialize in flat roofs or sloped ones, Sarkovich concludes, an environmentally friendly roof, is without question a great idea. "They'll have happier customers, " he says of contractors who build cool roofs, which is a good rea son to put away the asphalt shingles.