What’s the difference between open and closed cell foam insulations?

| by Jennifer Wilson
What’s the difference between open and closed cell foam insulations?

We get this question all of the time when we talk to people about their insulation choices. Both open cell and closed cell spray foam insulations stop the movement of air and slow down the transfer of heat. Both are good insulation products, because they provide insulation and an air barrier in one. You just have to understand the benefits of each so you can select the best product for your particular application.

Closed Cell

Closed cell foams have low vapor permeance due to their closed cell structure, hence the name. These foams, depending on thickness, may be considered a vapor retarder. In climate zones where vapor drive is a concern, a vapor retarder may be required depending on the local building codes. Also, closed-cell foams also have a high compressive strength and they add some structural strength to a building, which can make them a good choice for hurricane-prone areas.

Closed cell foams can be used for wall and ceiling insulation, but they can also be used for roofing insulation. The density of spray foam products is based on the weight of a cubic foot of the product. Closed cell wall foam typically has a density of 1.7 lb/cu. ft to 2.0 lb/cu. ft.  The R-value per inch of DuraTite™ 2.0 is 6.3. You can get a higher R-value in a limited space using closed cell.

Open Cell

The cell structure of open cell foam is, well, open of course. Open cell foam is only used for wall and ceiling insulation, not roofing, below-grade or any exterior applications.This is a good insulation to use in areas where you have equal or close to equal number of heating and cooling days. It adapts to seasonal temperature changes, allowing vapor to pass through and dry, which also reduces the chance of condensation.

Open cell insulation with its softer texture also has good sound dampening properties to reduce disturbance from airborne noises. Closed cell insulation does not have good dampening properties because it is a denser, more rigid product.

The density of open cell wall foam is typically 0.5 lb/cu ft. The R-value per inch for BioBased 501w® is 3.8.


Open-cell foams are significantly less expensive than closed-cell foams, because closed cell foams are much denser. But you also need to consider the importance of vapor drive in your region, R-value required by code, the depth of your wall cavities, your need for additional structural strength and sound dampening. Spray foam contractors who install Rhino Linings products, BioBased 501w® and DuraTite™ 2.0, could meet with you and discuss the right product for your project. Find a contractor in your area atwww.biobased.rhinolinings.com/local.

Topics: Building Green, Foundations, Indoor Air Quality, Insulation

Companies: Rhino Linings

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