green roof

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A Greener Roof-Literally

May 2007

Read this issue of Greentips online

 

Is your roof in need of replacement? If so, you might consider one of

the following high-tech roofing options, which reduce your home's

energy demand while avoiding the use of fossil fuel-derived asphalt

shingles.

 

Green Roofs

A " green " (or " living " ) roof is, in most cases, exactly what

the name

implies: plants growing on a building's roof. Depending on the slope,

strength, and size of your roof, you can have a roof covered with

grass, flowers, or even shrubs.

 

Besides looking pretty, green roofing offers numerous advantages:

 

Lower energy costs. Soil and plants add an extra layer of insulation

to your home, keeping it cooler in summer and warmer in winter. This

is particularly helpful in cities, where pavement and buildings

reflect heat and raise air temperatures about 10 degrees Fahrenheit.

 

 

Environmental benefits. Rooftop vegetation provides food and shelter

for insects, birds, and other wildlife, and plants' natural mechanisms

for filtering impurities help improve air and water quality. Green

roofs can also play a small role in flood prevention by reducing storm

runoff.

 

 

A longer-lasting roof. By providing a buffer against temperature

extremes, wind, and heavy rain, soil and plants can help protect the

underlying roof and extend its useful lifetime.

Solar Shingles

Why not put the sunlight your roof soaks up during the day to good

use? Photovoltaic (PV) shingles provide the same look, protection, and

durability as asphalt shingles but have the added benefit of

converting sunlight into electricity that can power your home (or

specific appliances), reducing the need for electricity generated from

fossil fuels and lowering your electricity costs.

 

PV shingles work best on south-facing roofs that are not shaded by

trees for a significant portion of the day. To determine the best

solar energy option for your home or find a professional installer,

visit FindSolar (see the related links), a joint project of the U.S.

Department of Energy and several professional organizations.

 

Cost

These environmentally friendly roofing options do cost a lot more up

front: approximately $10 to $25 per square foot (including

installation) for green roofs and $20 per square foot (materials only)

for PV shingles, compared with $1 to $2 per square foot for asphalt

shingles. Unlike asphalt shingles, however, green roofs and PV

shingles can save energy (and money) over their lifetime. Local,

state, or utility incentives (see the related links) might be

available to lower the up-front costs.