Overlays and Radiant Barriers
Using an umbrella or a wide-brimmed straw hat on a hot day at the beach helps keep the sun at bay. Technology is bringing cover-ups to roofing as well. These cool-roof coatings have advanced in recent years, and more developments are underway. Elastomeric sealants, foam sprays, ceramic-based paints and even "recycled waste cooking oil" treatments are making gains in providing ways to cool existing roofs by applying coats of overlay that reflect heat away [source: Raloff]. Built Up Roofing (BUR) is one method for applying cool-roof surface coatings over traditional asphalt or tar roofing. Different claims regarding ease of application, durability and energy savings vary by manufacturer, but researching cool-roof overlays or coatings and consulting with a local roofing contractor and local building codes can help in sorting through what's working well in different regions.
A technology on the flipside of an overlay is a roof underpinning, or sub-roof system called a radiant barrier. This under-the-roof application involves installing a reflective material, such as aluminum, or even a specialized reflective spray treatment that's installed into an attic or space between a home's interior and the roof. These act as barriers to keep heat up and out of a home. Costs vary from about 15 to 75 cents per square foot, but those with added insulating features can cost more [source: National Association of Home Builders]. But with a possible savings of about $200 annually (depending on the region), the installation fees may be worth the price [source: Oak Ridge National Laboratory].