THE GULF COAST Blog

Comparing Open Cell vs Closed Cell Spray Foam

Open cell spray foam and closed cell spray foam are both types of insulation that are applied as a liquid at high temerature & pressure, which then expand to fill the space they are applied to. However, there are some key differences between the two that should be considered when deciding which type of foam to use.

Both types of foam are air barriers and thermal barriers, but open cell spray foam is made of a less dense material and has small, open cells that are filled with air.  It also has a lower R-value, which is a measure of insulation's ability to resist heat flow.  Because of its lower density and R-value, open cell spray foam is typically applied at a thicker depth than closed cell, and is most often used in residential and commercial walls and attics for insulation purposes.

Closed cell spray foam, on the other hand, is made of a denser material and has closed cells that are filled with a gas that is not air. The higher density leads to a lower material yeild which makes it more expensive than open cell foam. However, with its higher R-value per square inch it is typically applied at a 2" to 3" depth as compared to 4" to 6" with open cell foam. Because of its higher density and R-value, closed cell spray foam is typically used in commercial and industrial applications, as well as insulating roofs, ceilings and walls of personal & commercial metal buildings, barns, sheds, crawl spaces, etc.

Another key difference is that closed cell foam is a vapor barrier (water resistant) whereas open cell foam is not. Because it has closed cells that are not filled with air, it does not absorb water, making it more suitable for areas that are prone to moisture (e.g. commercial rooftops, crawl space subfloors, etc.).

In summary, open cell spray foam is less dense and less expensive than closed cell spray foam, and is typically used for insulation in residential and commercial walls and attics. Closed cell spray foam is denser and more expensive per square foot than open cell foam, and is typically used in commercial and industrial applications such as insulating roofs, walls, and floors, and provides better water resistance and air sealing.