Flash & FOIL combines reflective foil and spray foam insulation to lower energy costs, address radiant heat flow, and provide a vapor retarder. In a 2- by 4-inch cavity, R-values range from R-11 to R-20 based on foam thickness and type.
A thin layer of spray foam provides an air seal and foil is then applied to the face of the studs where it expands and forms reflective air spaces in the cavity. A perforated version is available if vapor retarders are not desired.
