Will green roofs be the next hot trend?
Before establishing a green roof, consumers need to have some sense of what they want from it beyond the vague notion that they're good for the environment.
"Everything from roof materials to plant varieties
has to be picked for the issue you want to address -- storm-water retention, more
green space or thermal control," says Retzlaff. "Every green roof provides
some of each of these things, but to decide you want a green roof because it's
a good thing is not enough."
of lofty gardens
For example, Retzlaff cites a green roof in St.
Louis on the seventh floor of a children's hospital that has a pond and large
"It costs $200,000 a year to maintain,"
he says. "But the benefit is that when those children go through those double-glass
doors leading to the green roof, they can forget everything inside."
says Ford Motor Co. has a 10-acre extensive green roof in Dearborn, Mich., that
remains the largest in the U.S. "It has a 2-inch depth, so they have to irrigate
it. They catch storm water in retention ponds and irrigate with that."
Chicago, the mayor is interested in lowering the urban center's heat-island effects
that drive up temperatures. "He has been told by various research facilities
that if about 65 percent of downtown buildings had green roofs, that would lower
the heat by about 10 degrees," says Retzlaff. "So the city issues grants
to offset the costs of installation and will fast-track building permits if a
green roof is included."
Retzlaff expects G.R.E.E.N. to
become a resource for would-be green-roofers around the country. "Eventually
people will be able to contact us to find out exactly what growing medium and
plants are best for their climate and purpose."
Roberts says he sees more incentives -- and so more green roofs -- for commercial
buildings than homes right now, but there are several benefits that could make
them appealing to homeowners. They include increased insulation and the fact that
the additional garden materials make a roof more durable.
homeowners, a green roof on a low slope or flat roof can extend the life of that
roof many years by shielding it from rain water and ultraviolet sun rays, which
degrade roofing materials," says Roberts.
also filter out some air pollutants, he adds.
In addition to collecting storm water, reducing urban
heat and acting as insulation to cool down a building or home's occupants, green
roofs are seen by advocates as opportunities to increase food production, beautify
cities and provide sound insulation by absorbing, reflecting or deflecting noise
by machinery, planes and traffic.
For the average homeowner
concerned with rising energy costs, it's likely the insulation qualities of green
roofs would prove most appealing.
Dennis Yanez, national marketing
manager for Chicago's American
Hydrotech, says his company offers waterproofing and all the components for
garden-roof assembly, including Styrofoam, soil and plants. American Hydrotech
also offers a single-source warranty, which Yanez says is unique in the industry.
Clients are primarily architects and developers.
have not done a lot in the consumer market," Yanez says. "We do have
some homes that have our systems in them, but they're all higher-end, in the 7,000-
to 10,000-square-foot range."
That's because a homeowner
who wants a green roof, Yanez says, would have to start by hiring an engineer
or architect to design it. He estimates the price of building a green roof from
"the high teens to the low $20s" per square foot.
estimates costs at $9 to $25 per square foot for extensive green roofs and $25
to $40 or more for the intensive variety.
they have a growing appeal," Yanez says. "In general, sustainability
and green building has taken off in the past five or six years. Putting together
buildings that disrupt the environment as little as possible is becoming a real