Operational for over 100 years, CertainTeed is one of the leading manufacturers of roofing and building materials. It offers a variety of vinyl sidings, interior and exterior doors and windows, pipes, foundations, fences, railings and decks. It provides services to various contractors, builders, designers and distributors. The company designs and undertakes residential, industrial and commercial projects. It provides a selection of home insulation products that includes acoustical, thermal and energy-saving features. The company has a staff of more than 9,000 personnel that offers product design and development services. In addition, CertainTeed is a part of Saint-Gobain, which is a supplier of flat glass and abrasives. CertainTeed is headquartered in Valley Forge, Pa.