GAF mined New England quarries for the slate in its Americana roofing tiles. They are installed atop a specially designed waterproofing barrier, so there’s less weight than with other slate systems. The series comprises five slates whose traditional colors can be mixed and matched. The tiles are ¼-inch to 3/8-inch thick and ASTM C406-S1 rated—the highest rating for slate roofing. GAF, 800.766.3411;