Open cell spray foam is a less dense than other types of closed cell foam. It has a larger, less compact cell structure. It can be an air barrier as well as a water vapor barrier if it is sprayed at the correct thickness. It is often used in maintenance projects or other outdoor applications, but can be used anywhere where building performance needs improvements, but small enough to need just spray insulation in 5 gallon pails.
Open-cell spray foam in 5 gallon pails has an open cell structure where the cells are filled with air. The open-cell structure renders soft, flexible foam, with a density of about 0.5-0.8 pounds per cubic foot (pcf). Still air is the primary insulation medium in spray insulation, fiberglass and cellulose. These insulations work by reducing the natural air movement within these materials thereby reducing the ability of the material to conduct heat. The R-value per inch of spray insulation typically ranges from R3.6 to R4.5 per inch.