Spray Foam R Value Thickness

Closed cell spray foam r values.

Spray foam r value thickness.

The higher the r value of an insulation product the more effective the insulation properties. Hopefully today you learned that more isn t better in every situation. The r value is r 3 5 to r 3 6 per inch so filling a 2 4 cavity yields about an r 13. It has a lower r value per inch than closed cell foam and is vapor permeable.

More spray foam isn t always better. For 6 inches r 15 or r 19 etc. Spray polyurethane foam will have an r value of 6 6 per sq. In comparison an inch of blown fiberglass insulation has an r value of 3 1 3 4 and an inch of blown cellulose in an attic has an r value of 3 2 3 7.

Spray foam s r value does not decrease over time. Why spray foam insulation is so effective in meeting code requirements is that it has a higher r value per inch of product used than batts. Here are the installation methods from lowest to highest average r value per inch. For example closed cell spray foam depending on brand can offer an r 6 or r 7 per inch.

Depending on how close your calculated requirements are to the actual yield of the recommended kit size or quantity you may need more material to. Closed cell spray foam insulation. R values are additive so you can multiple the number of inches of insulation thickness times the r value to arrive at a total insulation value. Of thickness today tomorrow and 10 years from now.

Insulstar spray foam insulation is a spray applied semi rigid cellular polyurethane foam plastic insulation having a maximum thickness of 2 inches and a nominal density of 2 0 pcf insulstar has an r value of 5 77 per inch so the maximum thickness of 2 inches yields an r value of about 11 5. For example blown fiberglass typically has an r value of only r 2 to r 3 per inch depending on compression density and moisture. Closed cell spray foam has a far better r value per inch than other less effective insulations like cellulose fiberglass or even open cell foam. When using this spray foam insulation cost calculator it is generally a good idea to factor in about 10 extra spray foam insulation cost to account for over spray waste and yield variations due to your particular ambient conditions.

Note that the material the insulation is made from will change the r value as well. R value is the term given to thermal resistance to heat flow. In the case of spray foam roofing the goal is to maximize r. Blown in or loose fill insulation insulation blankets batts and rolls spray foam insulation and foam board insulation.