Timber Products. Made for roof construction, these radiant barrier plywood panels reduce utility costs year round by blocking 97% of radiant heat to keep attic temperatures 30 degrees cooler in warm weather and in winter, reflecting the heat back into the home, the company says. The structural plywood comes with foil on one side to save contractors from having to apply a separate barrier to the roof sheathing. The 4-by-8-foot sheets come in 15/32-, 19/32-, and 23/32-inch thicknesses. 800.547.9520. www.timberproducts.com.