STYROFOAM™ Brand SM Extruded Polystyrene Foam Insulation is a multipurpose extruded polystyrene board that helps to meet the needs of the commercial and residential foundation and slab market. The closed-cell structure of STYROFOAM™ Brand SM Insulation resists water absorption, enabling it to retain a high R-value (RSI) over time – a necessary property in below-grade residential foundation applications. STYROFOAM™ Brand SM Insulation helps to protect foundation dampproofing and waterproofing, especially during backfilling. It also provides a secondary barrier against groundwater leakage. With STYROFOAM™ Brand SM Insulation, the freeze-thaw cycling of the foundation wall is minimized, reducing the possibility of cracking. And a warmer foundation wall reduces the potential for condensation and adds to the thermal mass of the building.