Green roofs
Green roofs have a rubberized, waterproofing layer topped
by a root barrier, a drainage plane, lightweight soil and
plants. Some green roofs function as gardens where
people can stroll or dine, but many are passive spaces
devoted entirely to low-growing, water-thrifty plants, such
as sedum.
Green roofs offer many benefits:
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 Dramatically less runoff during storms.
are needed to see this picture.
 Better insulation, so it takes less energy to heat
the building in winter or keep it cool in
summer.
 A longer-lasting roof, because the
waterproofing layer isn’t exposed to harmful
ultraviolet rays from the sun.
 A cooler surface, which reduces the “heat
island” effect that causes urban temperatures to
rise.
Green roofs are unusual in this country, but they have a
Green roof on Seattle garage
long, proven history. In Germany, where government
designed by Harrison
regulations have encouraged them as a way to reduce
Architects, (206) 956-0883;
stormwater runoff, approximately 14 percent of the flat
harrisonarchitects.com
roofs are now covered in plants. In the United States and
Canada, interest in green roofs is growing rapidly, partly because of new, easy-to-install
modular systems, such as the one recently used on a community room at the Vineyard
Lane condominium project on Bainbridge Island.
Where green roofs make the most sense:
 On flat roofs or roofs with slopes up to 30 percent.
 Where the structure can support roofing that weighs at least 10 pounds per
square foot (the minimum weight of the various layers, soil and plants when
the soil is fully saturated).
Green walls are similar to green roofs, except that they are designed for vertical surfaces.
They can also be used on roofs that slope more than 30 percent.
For more information:
 Centre for the Advancement of Green Roof Technology located in Vancouver,
British Columbia, Canada: commons.bcit.ca/greenroof/
 Seattle Department of Planning and Development:
seattle.gov/dpd/GreenBuilding/OurProgram/Resources/TechnicalBriefs/DPD
S_009485.asp
 Analysis of existing green roofs in Seattle, from the engineering firm
Magnusson Klemencic Associates: mka.com/home/home_frame.html
See reverse side for green roofs on Bainbridge Island
Green roofs on Bainbridge Island
Grapevine Inn and Bistro, a
community center at Vineyard Lane
condominiums
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Architects:
O'Connor Kriegh Architects,
Bainbridge Island; 842-5490;
www.oconnorarchitects.com
Green roof system:
Elevated Landscape Technologies
Inc., (866) 306-7773;
www.eltgreenroofs.com
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The Vineyard Lane
project used modular
green roof sections,
which can be ordered
with plants already
established. They’re
installed like sod.
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The Clerestory House, Bainbridge Island
Architect:
Indigo architecture + interiors, Bainbridge Island;
855-9399; www.beingindigo.com
Green roof system:
G-sky; (604) 708-0611; www.greenrooftops.com
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This was a build-to-fit installation, but
company also sells modular roof sections.
Cost: $10 to $30 per square foot.
Company also sells modular green wall
system. See this product installed on
townhouses at 8023 Densmore Ave., Seattle.
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Modular green roof sections 1
meter square, including a DIY
version. Can be purchased as
materials-only or with plants
already established.
Cost: from $10 per square foot
for materials, $15 to $20 per
square foot installed.
Company also sells green wall
panels, about 20 inches by 20
inches.