Spray Foam Insulation
Home Improvement

Choosing Between Open-Cell and Closed-Cell Spray Foam Insulation

Insulation in the form of spray foam is applied to a surface as a liquid and then allowed to dry into a dense foam. As the foam is sprayed, its components react with each other and expand to form the insulating foam. Energy efficiency, soundproofing, and draught prevention are just a few of the many improvements over conventional insulation that can be attributed to this material. Spray foam insulation is versatile enough to be applied to any surface, making it a great option for hard-to-reach or irregularly shaped areas.

There are two primary types of spray foam insulation used to insulate structures; open-cell and closed-cell.

The foam’s density and the size of the cells make a significant difference between the two.

Because the cells in open-cell spray foam insulation aren’t completely closed, air can easily fill the spaces between them, reducing the foam’s density. Therefore, open cell spray foam insulation is less rigid and has a softer texture than closed-cell spray foam. In addition to being more affordable, it outperforms closed-cell spray foam insulation. Because of its high R-value and airtightness, open-cell spray foam insulation is commonly used for interior insulation in places like walls, attics, and crawl spaces.

Comparatively, closed-cell spray foam insulation is more rigid because its cells are larger and more tightly sealed. The high levels of insulation and support provided by closed-cell spray foam make it a great choice for use in places like exterior walls, roofs, and foundations. In addition, it acts as a more effective barrier against water, making it a good option in humid or flood-prone regions. The cost of closed-cell spray foam is higher than that of open cell spray foam, but it is also more effective and long-lasting.

Which should you choose?

Whether you go with open-cell or closed-cell spray foam insulation depends on your insulation project’s unique requirements, as well as the level of insulation and air sealing performance you’re hoping to achieve.

If you’re trying to decide between open-cell and closed-cell spray foam insulation, it’s smart to weigh the pros and cons of each. The best insulation solution for your home can be determined with the assistance of a professional insulation contractor.

Both open-cell and closed-cell spray foam insulation have their drawbacks, as listed below:

Open-cell spray foam insulation:

  1. Lower R-value: When compared to closed-cell foam, open-cell foam has a lower R-value per inch, suggesting that it may not be as effective at insulating.
  2. Moisture sensitivity: Since the open-cell foam is more likely to absorb moisture and lose its insulating properties with time, it should be kept in a dry environment.
  3. Vulnerability to damage: Because of its pliability and softness, open-cell foam is more susceptible to damage than its more rigid closed-cell counterpart.

Closed-cell spray foam insulation:

  1. Higher cost: Some consumers may be put off by closed-cell foam’s higher price tag when compared to open-cell foam’s lower one.
  2. Difficult to install: Closed-cell foam insulation is more difficult to install than open-cell foam and requires the use of specialised equipment and expertise.
  3. Health and environmental concerns: Some people are worried about the chemicals used in a closed-cell foam and the effects they may have on human health and the environment.


While there are many similarities between open-cell and closed-cell spray foam insulation, it is essential to select the appropriate foam for your needs. If you use the wrong foam insulation, you risk having timbers rot and air leakage, neither of which are desirable and could lead to expensive repairs down the road.

Open and closed-cell spray foam insulation systems from Isothane are available for residential, commercial, and industrial applications. Our professional spray foam insulation installers work across the country and are ready to assist you in making the right choice and putting it in correctly. Please browse our selection of spray foam insulation or get in touch with us today for free expert guidance.

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