Since its discovery in 1941, Styrofoam™ Brand XPS Insulation has a long and rich heritage as a sustainable building product, insulating to meeting core thermal, moisture, air and vapor performance requirements through its rigid foam board technology. STYROFOAM™ Brand Insulation is the original extruded polystyrene foam insulation, invented by DuPont/Dow and the first in a portfolio of products that would continue to grow and evolve to meet the needs of the building and construction industry and its related markets.