Spray Foam Insulation R-Value: Per Inch Guide



You might get some sticker shock if you price out spray foam insulation. It is expensive if done correctly by a professional contractor.

So, you want to make  sure it’s worth it. This story will cover spray foam insulation R-values and why you should, or most likely not use it.

What Is Spray Foam Insulation R-Value?

Spray foam insulation R-Values range from R-3.6 to R-7 per inch, depending on the type and manufacturer. Open cell foam offers R-3.6 to R-3.9 per inch, while closed cell foam provides a higher R-5.5 to R-7 per inch for superior thermal resistance.

Per-Inch Spray Foam R-Value by Density

1. High-Density 2. Medium-Density 3. Low-Density

Problems With R-Value of Spray Foam

There are a couple of main issues with spray foam and R-values. The first is just like some of the companies selling bubble wrap insulation, they have been known to be deceptive.

Spray Foam Type Doesn’t Matter in Stud Cavities

When you look at the charts comparing spray foam insulation R-values, you would think since closed-cell foam has the highest r-value, it is the best choice. Open-cell foam being R-3.6 and closed-cell R-5.5 per inch.

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