DOW STYROFOAM Brand SPF CA Insulation is a two-component spray-applied polyurethane foam insulation that, when properly applied, creates a seamless, monolithic barrier for protection against water and air. The SPF blend successfully incorporates a zero ozone-depleting blowing agent in the manufacturing process. For both new and retrofit applications, STYROFOAM Brand SPF CA Insulation is created from a unique polyol technology, which offers high foam yield and wide processing latitude. The closed-cell foam expands during application to fill cavities, cracks and crevices, blocking the uncontrolled air leakage that can threaten consistent, comfortable indoor temperatures (not to mention drive up energy bills).