XPS foam board is a rigid thermoplastic material manufactured from polystyrene. Polystyrene is a synthetic, hydrocarbon polymer derived from benzene and ethylene, two petroleum products.
XPS foam board is often used for above-grade insulation applications such as walls, ceilings, attics and roofs as well as for below-grade applications such as foundations and basements. When used above-grade, it can reduce thermal bridging and improve energy efficiency.