Before you install a spray foam product in your home or commercial building structure, it is very important to understand the difference between Open and Closed cell foam. The type you use will affect your cost and application method, as well as its performance.
Open Cell Foam
Where the tiny cells of the foam are not completely closed but are broken, and air fills all of the ‘open’ space inside the material, making the foam weaker or softer feeling than closed-cell foam. Density is measured by weighing one solid cubic foot of foam material. Open Cell Foams typically weigh 0.4 to 0.5 lb./cu. ft.
Open-cell SPF is inexpensive, with an R-value around 3.5 per inch, typically using water as the blowing agent.
Closed Cell Foam
All of its tiny foam cells are closed and packed together. They are filled with a gas that helps the foam rise and expand and become a greater insulator. These cells can be formulated to obtain many characteristics, the most common are size and density. Closed cell foam for insulation applications range in density from 1.7 lb./cu. ft. to 2.0 lb./cu. ft.
The advantages of closed-cell foam compared to open-cell foam include its strength, its higher R-value, and its greater resistance to the leakage of air or water vapor. The disadvantage of the closed-cell foam is that it is denser, requires more material, and therefore is more expensive.
Closed-cell SPF has an R-value of around 6.0 per inch (aged R-value) and uses high R-value blowing agents.