When cedar shakes and shingles are installed over solid sheathing, they are susceptible to rot and warping from excess moisture. Cedar Breather underlayment allows air to flow continuously between the roof deck and the shingles. The three-dimensional nylon matrix is 3/8 inch thick and comes in rolls 39 inches wide and 611/2 feet long (about 200 sq.ft.). Once the material is tacked in place, the shingles or shakes can be fastened through it to the deck. According to the manufacturer, Cedar Breather is unaffected by UV light or temperature extremes, and the added cost (as little as 10% for most roof installations) is balanced by the extended life of the roof. For more information, contact Benjamin Obdyke, John Fitch Industrial Park, Warminster,