Open-Cell Vs Closed-Cell Spray Foam

When it comes to spray foam insulation, many people wonder what the difference is between open cell and closed cell, as well if off-gassing occurs. Is one better than the other, are they used for different purposes? Will explain the differences below so that you can decide what is best for your situation.

Does spray foam insulation off-gas?

The quick answer to that question is somewhat. When we talk about off-gassing, what we are referring to is the VOCs that cause the off-gassing. So, how long does spray foam insulation off-gas? Well, it depends on those VOCs. More specifically, these refer to re-occupancy times. Once a spray foam insulation project is completed, re-occupancy time would be between two and four hours. Depending on where we are installing spray foam insulation to combat off-gassing we set up industrial-strength fans to create airflow to air out the area and remediate the issue of off-gassing.

Open Cell Spray Foam

Has a lower R-value and higher permeability. As its name suggests, open-cell foam is made up of tiny bubbles that are interconnected. The bubbles hold air, which provides insulation value, typically between R-3.5 and R-4.2 per inch. Open-cell spray foam expands to fill gaps and cracks as soon as it is applied. Instead of curing to a hard, smooth-surfaced mass, open-cell foam has a spongier feel.

Closed Cell Spray Foam

Provides a vapor barrier, a harder finish, and a higher R-value. The closed-cell foam we use is a "two-component" foam or polyurethane foam. Two chemical compounds are blended at the application nozzle, causing the expanding foam reaction. Even though it's more expensive to install than open-cell foam, closed-cell foam is often preferred for home insulation projects because it offers a higher R-value between R-6 and R-7.1 per inch making it easier to meet building code requirements.

Regardless if you are looking for insulation that will seal your home up and make it more efficient and comfortable while reducing operating costs you cannot go wrong with either open or closed cell spray foam insulation, but if you are looking for insulation that will make your home more efficient and comfortable while reducing operating costs, as well help with moisture then the no brainer choice is closed cell.  

In the grand scheme of things, it comes down to one what your overall goal is and two what and where you are insulating that is the deciding factor on whether or not to use open or closed-cell spray foam.