There are four major rigid plastic foam insulations commonly used for residential, commercial and industrial insulation: extruded polystyrene (XEPS), expanded polystyrene (EPS), polyurethane (PUR), and polyisocyanurate (PIR). Each type has individual characteristics and specific advantages and disadvantages for particular building applications.
Nonetheless, the stable properties of polystyrene, when combined with a unique foam extrusion process, produce an exceptionally useful product with benefits for nearly all construction and engineering applications.
Extruded polystyrene has a well established reputation for long-term reliability and superior resistance to the elemental forces of nature: time, water, cold, heat, and pressure.
Consider these forces when choosing insulation types.
THE EXTRUSION PROCESS
Extruded polystyrene foam begins with solid polystyrene crystals. The crystals, along with special additives and a blowing agent, are fed into an extruder. Within the extruder the mixture is combined and melted, under controlled conditions of high temperature and pressure, into a viscous plastic fluid. The hot, thick liquid is then forced in a continuous process through a die. As it emerges from the die it expands to a foam, is shaped, cooled, and trimmed to dimension.
This continuous extrusion process results in a unique foam product with a uniform closed-cell structure, a smooth continuous skin, and consistent product qualities, qualities unequaled by other insulation types.