Is gaf the same as CertainTeed?

No, GAF and CertainTeed are not the same company, they are two distinct, competing roofing and building materials manufacturers in North America, though both are leaders in asphalt shingles. GAF, officially GAF Materials Corporation, is headquartered in Parsippany, New Jersey, and is owned by Standard Industries, a privately held industrial conglomerate owned by the Heyman family. GAF is North America's largest roofing manufacturer with about 25 to 30 percent market share and is famous for its Timberline HDZ, Timberline UHDZ, Camelot, and Woodland shingle lines, plus Deck-Armor underlayment. CertainTeed is headquartered in Malvern, Pennsylvania, and is owned by Saint-Gobain, a French multinational founded in 1665 that is one of the world's largest building materials companies. CertainTeed makes Landmark, Landmark Pro, and Presidential shingles, plus siding, insulation, drywall, and ceilings. Both make fiberglass asphalt shingles that meet ASTM and CSA standards, but they have different technologies, GAF uses LayerLock and Dura Grip adhesive, CertainTeed uses CertaSeal and StreakFighter algae resistance. They are sold through the same distributors like ABC Supply, Beacon, and Home Depot and compete directly on price, warranty, and contractor programs. So they are competitors, not the same.