Spray Foam R Value Thickness

Note that the material the insulation is made from will change the r value as well.

Spray foam r value thickness.

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. More spray foam isn t always better. 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. The higher the r value of an insulation product the more effective the insulation properties.

Here are the installation methods from lowest to highest average r value per inch. Along with knowing the r value of a particular insulation it is also important to calculate the r value of a total system. For 6 inches r 15 or r 19 etc. 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.

Hopefully today you learned that more isn t better in every situation. Spray polyurethane foam will have an r value of 6 6 per sq. As a benchmark one inch of solid wood has an r value of 1. R value is the term given to thermal resistance to heat flow.

Blown in or loose fill insulation insulation blankets batts and rolls spray foam insulation and foam board insulation. 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. Of thickness today tomorrow and 10 years from now. 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.

In the case of spray foam roofing the goal is to maximize r. Closed cell spray foam insulation. Spray foam s r value does not decrease over time. 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.

A typical 2 4 stud filled with open cell spray foam will have an r value between 10 5 and 14. Closed cell spray foam r values. 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.