What is the Difference Between Open Cell and Closed Cell Spray Foam?

The main difference between open cell and closed cell spray foam lies in their cell structure, permeability, and density. Here are the key differences:

• Cell Structure: Open cell foam has cells that are deliberately left open, making the foam softer and more flexible. In contrast, closed cell foam has cells that are completely encapsulated, making the foam more rigid and dense.
• Permeability: Open cell foam is semi-permeable, allowing air and water to pass through it. Closed cell foam is semi-impermeable, restricting the flow of air and being less water absorbent.
• Density: Closed cell foam is much denser than open cell foam. Most open cell foam has a density of about 0.5 pounds per cubic foot, while closed cell foam can be over three times denser.
• Expansion Rate: Open cell spray foam expands to 3 inches of thickness, while closed cell foam expands to about 1 inch of thickness when sprayed. However, multiple applications of closed cell foam can be applied to achieve higher total R-values.
• Thermal Conductivity: Open cell foam has a higher thermal conductivity, making it less effective at preventing heat transfer compared to closed cell foam.
• Water Absorption: Open cell foam can absorb and retain water, while closed cell foam is more resistant to moisture.
• Soundproofing: Open cell foam performs better at absorbing and reducing sound than closed cell foam due to its open cell structure.
• Application: Open cell foam is ideal for interior applications with a higher risk of moisture, while closed cell foam is better suited for exterior applications and areas with high humidity levels.

In summary, the choice between open cell and closed cell spray foam depends on the specific needs of the application, such as the desired level of insulation, permeability, and density.

Comparative Table: Open Cell vs Closed Cell Spray Foam

Here is a table comparing the differences between open-cell and closed-cell spray foam insulation:

Open-cell spray foam is lighter, more absorbent, and has a lower density than closed-cell spray foam. It is also more eco-friendly and costs less to manufacture. However, closed-cell spray foam has a higher R-value, provides a better thermal barrier, and is more resistant to moisture.