Spray foam insulation is comprised of two chemicals that react when combined and cause the foam to expand when installed to fill cracks and crevices. Spray foam insulation both insulates and seals air leaks in one application. Spray foam insulation also dampens sound transfer, deters the growth of mold, and helps with drafts and cold floors.
Open cell spray foam is light weight and flexible due to its porosity. It acts as an insulator and air barrier and is vapor permeable.
Closed cell spray foam is heavier and denser than open cell spray foam. It also acts as an insulator and air barrier. Closed cell spray foam has a higher R-value than open cell spray foam and is more resistant to moisture. It is frequently installed in areas with higher moisture composition such as crawl spaces.