11 Jul EcoTip #12 – Cool Roofs for a Cooler City

Austin has become an urban heat island — the temperature in the city can be as much as eight degrees hotter than surrounding rural areas.  Roads, buildings, and other hard surfaces absorb and retain heat leading to surface temperatures 50° to 70° hotter. The removal of trees as the region develops also removes the cooling effects that vegetation provides.

Turning a rooftop into a garden provides insulation to the building below and helps cool the building. A green roof also improves the air by absorbing carbon dioxide, and reduces water runoff during heavy rains.

Ladybird Johnson Wildflower Center suggests using regionally appropriate native plants to preserve the natural heritage of the region. Plants on their list include a variety native grasses, Texas sedge, crossvine, red yucca and many more.

Other Cool City Ideas:

• If your roof doesn’t lend itself to gardening, use light-colored reflective material when you install a new roof. Light-colored roofs use up to 40 percent less energy than dark colored roofs. The City of Austin offers reflective roof-coating rebates.
• Pave roads and parking lots with light colored or porous materials
• Plant trees to provide a canopy of shade