CARMEL, Ind. (May 1)—Firestone Building Products Co. has raised prices across-the-board for its commercial roofing products, citing sharp cost increases for its key raw materials. The price hikes include Firestone's single-ply and asphalt-based membranes and polyisocyanurate insulation. Current pricing for the company's single-ply products is guaranteed for orders shipped through May 31, followed by 4- to 6-percent increases on shipments from June 1 through Sept. 30. Firestone's affected single-ply products include RubberGard EPDM, UltraPly thermoplastic olefin and UltraPly 78+ polyvinyl chloride membranes.