Hoover Treated Wood Products is the largest producer of fire-retardant treated wood in the world. Hoover is an American-owned, full-line treating company with the industry's most effective products and support. Our fire retardant formulations are licensed to a select group of licensee treating plants in North America and the United Kingdom. Hoover was founded in 1955 and is a subsidiary of Ply Gem Industries, a leading manufacturer and distributor of specialty building products. Ply Gem was founded in 1943 and was acquired by Nortek in 1997