CHARLOTTESVILLE - Virginia's roofscape is turning greener.
Atop the Albemarle County Office Building in Charlottesville, plants
cover 9,000 square feet of what was once a tar-and-gravel roof. The delicate
purple and yellow flowers are healthy despite the drought.
The green roof -- a groundcover of Shale Barrens, Dragon's Blood, Blue
Spruce and Jellybean varieties of sedum -- is a pretty sight.
Throughout Virginia, such roofs are being planted in a fledgling movement
to add green space where there was none before. A green roof is simply
plants on top of a roof covered with protective layers and soil.
The University of Virginia aims to replace many of its flat traditional
roofs with green roofs and to plant them on some newly constructed ones,
including sections of the massive South Lawn project currently under
construction.
Over the past several years, U.Va.'s board of visitors has pushed to make
the campus environmentally healthy.
In downtown Richmond, the 12,000-square-foot roof of the four-story
SunTrust Bank building on Main Street is covered with a quilt of greenery,
an experiment in making the urban world cleaner and more aesthetically
pleasing.
"It looks good. It's not hard to do. There's little
maintenance," said Gregor Patsch, the water resources engineer who
oversees the green roof for Albemarle.
Walter Swartley, facilities manager for SunTrust in Richmond, said of his
two-year-old green roof, "To go green is an additional expense, but I
think it's the right thing to do for these large expanses of roof,
especially in an urban environment."
Elsewhere:
In Norfolk, Virginia Wesleyan College has green roofs on several of its
buildings.
In Arlington County, green roofs cover the county government center and
the private Palazzo condominium.
In Leesburg, a 6,500-square-foot green roof covers the Howard Hughes
Medical Center.
In Quantico, a green roof was installed over the exhibit galleries at
the National Museum of the Marine Corps and Heritage Center, which opened
in November. Green roofs cover a few private homes in Virginia, but
experts say demand is much smaller because of the greater expense.
Across the nation and in Virginia, the number of buildings with green
roofs is increasing. The movement started in Europe decades ago and spread
to America about 10 years ago, slowly growing into something beyond a fad.
Chicago has the greenest roofs of any city in the nation: More than 100
building projects incorporating green roofs, encompassing about 1 million
square feet, are now under way. Mayor Richard Daley, a big proponent of
the movement, offers incentives to private companies to build green roofs,
one being to allow extra floors on the building.
Ford Motor Co. created a 10.4-acre green roof -- one of the world's
largest -- over its Dearborn, Mich., truck plant final-assembly building.
The roofs come in two types: intensive and extensive. Intensive roofs
are similar to what used to be known as rooftop gardens. They require at
least 1 foot of soil and usually feature large trees, shrubs and elaborate
irrigation and drainage systems. Extensive green roofs are much simpler
and require only from 1 to 5 inches of special soil.
U.Va. is planting an extensive roof adjacent to an intensive one on an
addition to Rouss Hall on the grounds, said Helen Wilson, a landscape
architect at the school.
"People can enjoy the roof. They can take a book or laptop out
there and enjoy the space, and there are a lot of windows that look down
on the roofs," she said.
Extensive green roofs typically contain low-maintenance,
drought-resistant plants such as sedum. Sedum plants are hardy and
attractive, can withstand high temperatures and drought and mature into a
quiltlike carpet. Maintenance consists of some watering and occasional
weeding.
"The future for green roofs is very bright," said Steven
Peck, the president of Green Roofs for Healthy Cities, a nonprofit
industry association. "Green roofs are a force for cleaner air and
water and for aesthetics. There's something about that transformation that
grabs you."
Expense is a major drawback. Depending on the type and size, a roof can
cost two to five times as much as a conventional one. Many of the public
projects are being built with grants from cities, such as in Chicago, or
from private groups such as Virginia's Alliance for the Chesapeake Bay,
which provided grants to Albemarle and SunTrust Bank.
One advantage is water management. Rain falls on traditional flat roofs
of buildings and pours down downspouts, across parking lots and into storm
drains that lead to streams and rivers that flow into the Chesapeake Bay.
On the way, the water picks up many pollutants.
But green roofs can absorb up to 60 percent of the rain that falls on
them. Patsch said Albemarle's roof soaks up thousands of gallons of water
during a good rainfall, much of which evaporates back into the atmosphere.
Water that does run off tends to be cleaner because it has filtered
through the plants and soil.
Drain-off water is also cooler because green roofs stay much cooler
than conventional roofs. "Putting hot water into streams is
detrimental to aquatic life," said Patsch.
Green roofs are more efficient at reducing air conditioning than
heating costs. This summer, Patsch said, he measured temperatures at 140
degrees on an adjacent roof and only 100 degrees on the county's green
roof.
"The air conditioning just doesn't have to work as hard," he
said.
Green roofs also reduce the "heat island" effect of hot air
that encompasses cities whose concrete, metal and asphalt radiate heat.
The greenery also lengthens roof life by two or three times and reduces
carbon dioxide through photosynthesis, lessens air pollution and reduces
outside noise heard inside a building.
There is also an undefinable advantage to having a growing roof, said
Peck. "We need green space," he said. "Humans need to be
surrounded by natural forms. Green roofs speak to that."
