Styrofoam™ was invented by Dow more than 50 years ago and identified by the distinctive Blue™ color. Dow invented a process for extruding polystyrene to achieve a closed cell foam that resists moisture.
How does it work? Resistance to the flow of heat is measured in "R-value", the higher the R-value, the harder it is for heat to get through. STYROFOAM extruded polystyrene insulation is rated at an R-value of 5.0 per inch at 75°F. The material R-value for the entire wall assembly is derived by adding an R-value of Styrofoam0.08 per inch for concrete along with an interior air film coefficient that produces an R-value of 0.68 and an exterior air film coefficient that produces an R-value of 0.17. A wall utilizing STYROFOAM T-MASS Technology with a 2-inch exterior layer and a 4-inch interior layer of concrete along with a 2-inch layer of STYROFOAM extruded polystyrene insulation would result in a material R-value of approximately 11.33.