Felt is heavy, cumbersome to install and a little on the old-school side. CertainTeed’s new DiamondDeck underlayment is installed on steep-slope roof decks and serves as a water-resistant layer beneath roofing shingles. It’s light, easy to carry and includes a special top surface treatment for superior traction and slip resistance in both dry and wet conditions. The 4-foot wide, 250-foot long rolls help speed application and maximize roofer ergonomics. A light gray surface color keeps the roof cool during installation. Links:
[1] http://www.certainteed.com