STYROFOAM™ Brand DECKMATE™ Plus Extruded Polystyrene Foam Insulation is designed specifically to provide a higher compressive strength or additional membrane support for conventional low slope roof applications. The board has smooth, high-density skins, with a closed cellular structure. STYROFOAM™ Brand DECKMATE™ Plus Insulation has excellent insulating characteristics, low water absorption and excellent compressive strength. Properties imparted by DOW's extrusion process coupled with the hydrophobic nature of polystyrene give STYROFOAM™ extruded polystyrene insulation high resistance to both water and water vapor. It exhibits dependable and predictable long-term mechanical and thermal performance, even in the most severe environments due to its Durability and reusable features.