Open Cell vs. Closed Cell Spray Foam Insulation: What’s the Difference?

Both closed-cell and open-cell spray foam insulation share a common purpose: they are designed to balance a building’s inner and outer thermal envelope. With spray foam insulation, soundproofing, vibration control, and fire resistance are additional benefits with little to no trade-offs. 

However, it is important to note that the performance of either type of foam insulation depends on the density and thickness of the foam, the material that is being sprayed, and the square footage of the project.

If you don’t know the difference between the two types of foam, it’s easy to make a costly mistake and end up with a solution that doesn’t live up to your expectations.

Open Cell vs. Closed Cell Spray Foam Insulation: What’s the Difference?


Open-cell spray foam, also known as a low-density foam, uses about 0.5 lbs. of open holes that allow small amounts of air to pass through, thus creating an insulating “bubble” around a building. In this way, you can control the amount of air that is allowed in and out of the building envelope. 

Closed-cell spray foam uses larger cells, which is why it’s known as a medium density or 2.0 lbs. foam, which is filled with chemicals that hold the air in. This type of insulation does not allow air to pass through, and the chemical mixture is designed to prevent moisture from migrating through the foam. 

This makes it easier to maintain the temperature and air quality of a home, so it’s great for insulation projects that have large, open cavities in the building’s walls and roofs. Among key benefits also include higher tensile and bond strength, lower noise, and more. 

Both closed-cell spray foam and open-cell spray foam are designed to balance a building’s inner and outer thermal envelope.


Open-cell spray foam is a great solution for an application that requires quick, easy installation. It is often used for small projects such as basements, garages, homes, RVs, etc. Since it is less dense than closed-cell insulation, it allows for a little more airflow, which is ideal for quick installations where water may contaminate insulation.

Closed-cell foam provides a solution that is heavy, but it is a great option for improving a building’s insulation. It offers a higher R-value because of lower air content and it offers more strength, more ease of application, and much lower moisture migration. It is a great solution for large jobs like commercial buildings, attics, and even large walls and roofs.

Moisture Barrier

Closed-cell spray foam is extremely effective at preventing moisture penetration and is the perfect option for situations where moisture will be an issue.  On the other hand, the open-cell spray is moisture-permeable and is used in areas where water is present, as it is not as effective at preventing moisture from entering.

The Bottom Line: Choosing Between an Open Cell vs Closed Cell Spray Foam

Spray foam insulation is a great solution for many applications, but it is important to know the benefits and limitations of each product. Making sure the insulation you choose will meet all of your requirements is the best way to ensure that your project is a success.

If you are looking for a fast, simple solution for a small project, open-cell spray foam is the recommended solution. However, if you are looking for a heavier, more effective solution for a larger building, closed-cell spray foam is a perfect choice.

Are You Looking for a Foam Insulation Contractor in Canada?

As one of the best spray foam companies in Toronto, we can help you find the best spray foam product delivered to your job site. Get in touch with us and see how we can help you choose the best insulation option for your space!

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