ABOUT OPEN-CELL SPRAY FOAM
Open-cell spray foam is much lighter and softer than closed-cell spray foam and gives no added structural value to the building or roof. In open-cell spray foam, the cells or bubbles are not completely closed, giving it the name "open-cell."
The cells continually expand until they burst, and, as a result, the cells are now open to each other. Open-cell foam can absorb water. If it is exposed, it can harbor mold. Because open-cell foam is less dense, it requires less material, therefore costs less to apply.