Green Roof Unveiled in West Austin

A.D. Willis Company leads the way in green roof technology.

A.D. Willis Company has completed the design, coordination and installation of a 1,200-square-foot green roof at a home in the Lake Austin Estates Community west of downtown Austin. "We've been involved in several green roof projects in the Austin area, but this is the first one we've taken from start to finish," says Charlie Glaze, A.D. Willis Company marketing and production manager. "It will not only provide our client with a beautiful outdoor living space, but the green roof will also promote energy savings and a positive impact on the environment."

Green roofs have been found to support the environment by:

- Reducing energy costs

- Reducing storm water run-off

- Reducing the heat island effect

- Extending the life of the roof's waterproofing membrane, protecting it from extreme temperatures, hail, foot traffic, and direct sunlight

- Reducing noise pollution

- Improving the atmosphere by filtering pollutants, absorbing carbon dioxide, and emitting oxygen

A green roof assembly consists of a series of components, each with a specific purpose to make the roof function properly. Carlisle provided their Roof Garden Waterproofing System for this project. A.D. Willis Company first replaced the existing roof system on the portion designated to be green with a 60 mil. TPO (thermoplastic polyolefin) single-ply waterproofing membrane. Next, additional layers were applied in a set order: a protection fabric, root barrier, drainage mat, and water retention fabric. Rubber pavers were installed in traffic areas, and then nearly eight tons of growth media (a blend of organic and inorganic components) were brought in which was bordered by a perforated aluminum edging. A drip irrigation system was then installed, and finally the plants were put in followed by a top layer of mulch. The project took approximately three months to complete.

"The growth media in the planting areas is 6" deep, which puts significant weight on the structure," says Robert Herbert, A.D. Willis Company service manager. "If you're considering a green roof, first consult a structural engineer or architect to determine if the site can support it."

A green roof costs anywhere from $15 to $25 per square foot, and although the initial costs of installing a green roof are greater than a conventional roof system, the long-term benefits and energy savings outweigh the original investment. "Due to a green roof's natural thermal insulation qualities, a building's heat gain is reduced keeping it cooler in the summer and warmer in the winter," said Glaze.

Glaze added, "We're learning more and more about green roofs every day and how they perform in the warmer, drier climates like we have here in Austin. So I'd like to thank two of the experts in the field for their guidance and assistance on this project - Brian Gardiner of Austech Roof Consultants and Casy Boyter of Casey Boyter Gardens and Green Roofs." 

To view a video documenting the step-by-step installation of this green roof, click the YouTube link at the top of the page.