Raise the Roof and Do It Green
April 24, 2011
By WeatherBug Meteorologists
Looking for ways to lower your utility bills while also doing something to help out the environment? If so, consider installing a green roof.
What is a green roof? It is a building`s roof that is either partially or fully covered in vegetation. These roofs can be retro-fitted to existing structures or be part of the planning on new construction, both residential and commercial. The type of vegetation used depends on the climate in which the roof is installed. These roofs require a depth of soil or compost that is determined by the type of vegetation to be grown and the pitch of the roof, but can designed with as little as a few inches.
Green roofs are not only visually appealing, but also highly efficient energy savers. The roofs reduce both heating and cooling costs in the buildings on which they are installed. The magnitude of cost savings varies with location, type of greenery used and other factors, but yearly savings of 20 to 50 percent have been reported in mid-latitude climates.
These environmentally friendly roofs also act to reduce the amount of warming of its surroundings. Fully exposed roofing materials, such as asphalt and concrete, tend to absorb and then reradiate heat energy whereas the vegetation of a green roof greatly reduces these effects. This reduction in warming of its surroundings in turn reduces the so-called `urban heat island effect. `
Studies, including those conducted by NASA, have shown that plants lower air pollutants as part of photosynthesis, creating lowered ground ozone. Green roofs have the added benefit of reducing the rate and quantity of storm water runoff. This lightens the burden on municipal drainage systems, particularly during intense rainfall.
Initial costs of installing a green roof vary by climate, the type of design and vegetation used, but generally ranges from $8 to $25 per square foot. Despite this substantial initial investment, green roofs continue to enjoy growing popularity in the U.S. with Chicago, Atlanta and Portland, Ore., as well as other cities leading the way by offering tax breaks and other building permit incentives to encourage their installation.
Story image: depicts a green roof on top of Atlanta`s city hall and is courtesy of the U.S. Environmental Protection Agency.
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