Are you looking for the right polystyrene foam board for your project, but you're not sure if you should choose expanded polystyrene or extruded polystyrene foam board? Well, this article is for you. Polystyrene is one of the most common synthetic insulator materials used in insulating houses and creating artistic projects. It is classified into two types: Extruded polystyrene and Expanded polystyrene. The use of extruded (XPS) and expanded(EPS) polystyrene in construction projects offers excellent compatibility, flexibility, and thermal efficiency.