Styrofoam Brand DeckMate Plus Insulation is a Type IV extruded polystyrene foam product for conventional, low-slope roofs. Styrofoam™ Brand Deckmate™ Plus Extruded Polystyrene Foam Insulation is designed specifically to provide a higher compressive strength and additional membrane support for conventional low slope roof applications. Styrofoam™ Brand Deckmate™ Plus Insulation is an extruded polystyrene foam. 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. Durable and reusable, it exhibits dependable and predictable long-term mechanical and thermal performance, even in the most severe environments.