How a Green Roof Can Improve Your Home

August 10, 2012

Texas AgriLife Research and Texas AgriLife Extension Service are collaborating with building owners in Houston to find ways to build and maintain green roofs for energy savings. (Texas AgriLife Research photo by Kathleen Phillips)

Wish you had a bigger garden? It’s likely you can’t extend your backyard, but there may be another way to get more green space: on your roof!

Green roofs have long been popular in Europe and have started to become more popular in the United States. Why? Because they offer homeowners countless benefits beyond just looking good:

  • Last longer than conventional roofs
  • Reduce energy costs
  • Absorb storm water
  • Improve air quality

There are two main kinds of green roofs: intensive and extensive. An intensive green roof has strong structural support, allowing it to house bushes, trees, paths, and benches, functioning as a rooftop garden. Extensive green roofs, on the other hand, require less support and little maintenance, support only ground cover for environmental benefits.

The upfront cost of installing a green roof is not inexpensive since they require professional design, structural analysis, and multiple systems. The simpler extensive green roof starts at around $8 per square foot. However, this price is predicted to drop as they become more popular.

It’s also expected that more incentives will be offered since green roofs offer many benefits to cities. The greenery and soil absorbs and filters water that would otherwise flow through polluted streets, over-taxing sewer systems. Green roofs also improve air quality by removing pollution and producing oxygen, and help keep temperatures down since they use heat energy as water evaporates from leaves.

Still, even without a reduction in price or any additional incentives, you will ultimately benefit from the installation of a green rooftop financially because of their durability and reduced energy costs. One Canadian study found that a simple 6-inch extensive green roof reduced summer energy use by 75%! And of course, if you choose to go with an intensive green roof, you are also adding to the livable space in your home.

To install a green roof on your home, you will need to choose between an intensive or extensive design. For an intensive design, you’ll need to contact a certified contractor since it may require some structural changes to support the weight of the new roof.

However, if you decide on an extensive green roof, it may be possible to do it yourself. To partially cover your roof, it is recommended that the green area is placed on a flat or low-sloping area below a higher roof to allow it to slow and filter runoff from the rain. For a slope with a rise steeper than three feet for every 12 feet of length, you will likely need a system for holding the soil in place.

You’ll also need to ensure that your roof can handle 27 pounds per square foot. A good test is to walk on your roof and look for any bounce or wobble. If in doubt, contact a professional to verify, and ensure you follow local building codes.

Installation involved placing a mult