Since its founding in 1947, ALSCO has reigned supreme as the largest supplier of residential aluminum building products in North America. Headquartered in Raleigh, North Carolina, ALSCO manufactures a broad range of residential aluminum building products for the new home, home-improvement and remodeling markets. ALSCO’s product line includes aluminum trim coil, soffits, accessories, siding, rainware, roof moldings and painted aluminum coil. All are primarily used in conjunction with vinyl siding.