Is There a Difference Between Spray Foam Insulation and Injection Foam Insulation?

Spray foam insulation and injection foam insulation may sound the same and even look the same at a quick glance. Heck—these two terms are exchanged as the same type of residential insulation foam on a regular basis! However, they are quite different. 

Although both forms of insulation are open-cell, they do not operate the same way. Spray foam is sprayed onto the material it will insulate and then expands as it dries in order to create more insulation between two materials. Injection foam is injected onto the material to insulate and does not expand

The main difference between spray foam and injection foam is dependent upon the expandability, or rather, the lack of expandability. 

Generally, injection foam is used for insulation purposes on exterior surfaces. We would not want to apply open cell spray foam (which expands) to an outside wall because of the potential pressure added to the inside of the exterior facing wall when the spray foam expands. Using open-cell injection foam is a better fit for these surfaces because they do not expand when drying and setting. 


Are you unsure if you should use spray foam or injection foam insulation for your home? 


First, here are some questions to analyze about your property.

What type of space are you looking to insulate?
Is this a new build or an existing home?
What is your budget?


It’s important to consider these questions because it will help narrow down what type of insulation is best for your property. With regards to price, it’s also crucial to remember that the initial cost of materials and insulation will also be reflected over long-term savings, namely utility bills.


Now, let’s take a look at the pros of each insulation type.

Pros for Spray Foam Insulation
  • Two types, depending on what you need: open-cell or closed-cell spray foam
    • Open-cell is semipermeable for moisture control and is often less expensive than closed cell
    • Closed-cell has a higher R-value than open-cell and has a rigid texture for extra strength
  • Weather barrier for year-round protection
  • Highly energy efficient

While the R-value of spray foam insulation is not quite as high as injection foam, it is more adaptable for cracks, small spaces, and unfinished walls. 


Pros for Injection Foam Insulation
  • Drywall does not need to be removed to properly insulate
  • R-value can be as high as 18 per inch once installed
  • Significant noise reduction

Injection foam lends to a quick installation and adds to improved air quality, but it is better suited for insulating exterior walls or retrofitting existing homes.

At MPI, we carefully evaluate each space to properly assure we recommend the best materials for insulating your home. We offer spray foam insulation installation in residential spaces, like attics and crawl spaces, and we also service commercial buildings. 

If you’re interested in using spray foam to insulate your home, or if you’re looking for a professional insulation consult, please give us a call at 844-MPI-FOAM.

Note: MPI Foam does not offer injection foam insulation.


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