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| Layers of a
Green Roof: |
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A green roof, or rooftop
garden, is a vegetative layer grown on a
rooftop. Green roof structures can become net
producers of energy, clean water and air, as
well as part of healthy human and biological
communities. Green roofs provide shade and
remove heat from the air, reducing temperatures
of the roof surface and the surrounding air.
Green roofs can be installed on a wide range of
buildings, from industrial facilities to private
residences. They can be as simple as a 2-inch
covering of hardy groundcover or as complex as a
fully accessible park complete with trees.
Although green roofs may have a higher initial
cost than traditional roofing, over its
lifetime, the green roof would save about
$200,000. Nearly two-thirds of these savings
would come from reduced energy needs for the
building with the green roof. Depending on rain
intensity and green roof soil depths, runoff can
be absorbed between 15 to 90 %, thereby
considerably reducing runoff and potential
pollutants from traditional impermeable roofing
surfaces. Plants intercept and delay rainfall
runoff as nature intended, alleviating combined
sewer overflows, and eventually return water to
the surrounding atmosphere by evaporation and
transpiration.
Green roofs can never replace natural areas, but
they can offer some of the benefits of natural
areas. In addition to maintaining stormwater
runoff, they can create habitats for birds, bees
and butterflies, turning your once boring roof
into an aesthetically appealing part of your
home or business. |
| “Green
Roofs”: Alternatives to Traditional Asphalt
Singles |
Did you know?
• Nearly 75 percent of all roofs in the
U.S. are covered with asphalt shingles. Asphalt
shingles contain petroleum products and are
difficult to reuse or recycle because of that
very fact. Some older varieties contain
asbestos and other harmful materials. The
average life span for asphalt shingles is about
20-25 years.
• Each year, the U.S. manufactures and
disposes of an estimated 11 million tons of
asphalt shingles. Of this waste, 10 million
tons is from tear offs from re-roofing and 1
million tons from manufacturer waste. The U.S.
EPA estimates that asphalt shingles make up
nearly 10 percent of the total building-related
waste stream in landfills, decomposing very
slowly and emitting methane gas. |
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“Greener” Roof Alternatives |
“Living” Roofs- Living roofs contain a
layer of soil with plants growing on top,
preferably native plants. Some systems are
installed in flat containers that can be moved
or easily replaced.
Sheet Metal Roofs-
Roofs made out of sheets of metal are easy to
install and last for decades, making them very
sustainable. They come in a variety of colors
and are made with varied amounts of recycled
content.
Solar Shingles-
Solar roof shingles look just like normal
roofing shingles but contain a thin layer of
photovoltaic film which generates electricity.
Although one shingle by itself will not produce
much energy, an entire roof covered with these
shingles can produce enough power for your
entire home.
Recycled Shingles-
There are several roofing shingles on the market
that contain various amounts of recycled
material. These products can be manufactured to
look like any type of roofing shingle and help
keep waste out of our landfills.
Aluminum Shingles-
Often referred to as the “miracle metal,”
aluminum shingles are lightweight, durable,
highly reflective and made out of recycled
material. And, of course, they can be recycled
again when replaced. |
| From
roof to road … |
Some highway departments now
use old asphalt shingles from tear-offs as part
of their new road mix. Up to 5 percent of new
road asphalt mix in Illinois contains ground up
asphalt shingles from local homes. The Illinois
Tollway Authority leads the way as part of their
attempt to green up the tollways.
The next time you tear off and replace your
asphalt roof, make sure your contractor takes
them to an approved recycling facility that
turns them into new roads. |
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| Benefits of Green Roofs |
Living,
Vegetative Green Roofs:
• Control stormwater runoff, erosion and
water pollution
• Mitigate urban heat-island effects,
cooling and cleaning the air
• Conserve energy and reduces greenhouse
gases
• Double service life of roof, reducing
both costs and landfill space |
Metal
and Recycled Green Roofs:
• Use recycled material that can again be
recycled
• Double service life of roof, reducing
both costs and landfill space
• Use less raw materials, thus, protecting
our natural resources
• Reflect the sun and keeps homes better
insulated |
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