The Green Roof: Good For Your Home And Good For The Planet

Green roofing involves the addition of soil and plants to your roof. There are two types of green roofs. "Intensive" green roofing requires several feet or soil and large plants. This type of large garden on a roof is more suitable for larger buildings. "Extensive" green roofing is more compatible for residential roofing, requiring only a few inches of specially mixed soil and a few smaller plants or ground cover. Extensive green roofing has many benefits for homeowners and their surrounding community.

How is extensive green roofing installed?

Green roofing material is installed in layers. These layers are applied in the following order:

  1. A waterproof membrane is first applied to the roof. This is done either by using a hot asphalt rubber mix, or a cold rubber coating that is treated with a root resistant material. Both of these methods keep water and plant roots from finding their way to the roof.
  2. A layer of pebbles or a composite mat is applied for water drainage.
  3. A filter cloth is then placed upon the drainage layer.
  4. A growing medium is added for the top layer, with hardy, drought resistant plants added to finish the application.

Why install a green roof on your home?

A green roof cools your house by providing shade, which keeps the suns' rays from heating your roof. This heat would normally transfer into your home, so you save on air conditioning costs. Plants also cool the air through evaporation.

Green roofing also helps to keep your home warm, by providing insulation that helps prevent heat from escaping through your roof. Outside noise is reduced by the extra buffer that is provided by the layers of green roofing, and the lifespan of the roof itself may be extended by the additional protection that green roofing offers.

The multiple layers of a green roof absorb and filter most of the rainwater that falls on your roof. They remove pollutants that would otherwise end up in local waters. Flooding that is caused by the rush of storm water is reduced by the absorption and gradual release of rainwater by the layers of green roofing.

Urban areas are especially affected by large expanses of black roofs, which create an effect that intensifies summer heat. Green roofs don't absorb the sun's heat, and the plants cool the surrounding area through evaporation, much as they do for the home. They also absorb pollutants from the air, and synthesize carbon dioxide, which is acting as a catalyst for climate change.

You will need to be sure that your home and roof is structurally able to sustain the additional weight of a green roof. Hire a residential roofing contractor that is familiar with green roofing to determine suitability, offer a price estimate, and install it. If the cost to benefit ratio is acceptable, then give it a try. Your home and your planet will thank you.


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