As consumers become more energy-conscious and new construction codes emerge, energy-saving “cool roof” products are gaining popularity. Some can lower attic temperatures as much as 30 degrees, giving air conditioners and utility bills a break.
Products such as Coastal Plywood Co.'s SolarPly and Ainsworth's Thermastrand feature plywood sheathing laminated with foil to reflect UV rays and heat away from the roof. “A worry early on was that the reflection would heat roof shingles too much, but we've found it only raises the shingle temperature about two degrees,” says Jason White, national sales manager for Coastal Plywood Co. Tyvek AtticWrap by DuPont can be installed across rafters to reflect infrared rays, followed by furring strips for ventilation, and roof decking. For low-slope roofing, Certain-Teed recently introduced the CoolStar coating on its Flintglas cap sheet (right). The factory-applied white acrylic coating has an initial solar reflectance of 0.77 and a thermal emittance of 0.92.
“In the renovation market, you may not be able to expand a building much or start from scratch, but you can improve its performance, and that's where a lot of these products come in,” says Joe King, global technology manager for DuPont Building Innovations.
Husnu Kalkanoglu, director of research and development for CertainTeed's Exterior Products Group, notes that reflective roofing materials may not be suitable for all homes. “In California, Florida, or Texas where it's hot, they offer the chance to lower energy bills by keeping the house cooler. But they won't provide the same savings in cooler climates,” he says. “Contractors must educate themselves about available products and technologies, and look at performance, value, and aesthetics for each project.”