Spray Foam Insulation Thickness R Value

Closed cell spray foam r values.

Spray foam insulation thickness r value.

For example if you have a type of insulation that has an r value of r 5 per inch of thickness you will need a depth of 6 inches of this insulation installed in your attic to reach r 30 if you live in zones 2 or 3. Recommended home insulation r values. The r value of fiberglass insulation is approximately 2 2 per inch so much thicker fiberglass insulation is required to achieve the same r value of 38. For 6 inches r 15 or r 19 etc.

The higher the r value the better the thermal performance of the insulation. R value is a measurement of thermal resistance and measures the ability of heat to transfer from one side of an object to another. The r value depends on the type of insulation its thickness and its density. Open cell spray foams are between 5 and 1 lbs per cubic foot and have an r value of 3 0 4 0 per inch of insulation.

Closed cell spray foam insulation. These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation. R value is a measure of insulation s ability to resist heat traveling through it. According to industry publication fine home building the r value for open cell spray foam is between r 3 5 r 3 6 per inch.

The common denominator among varieties of insulation is the r value. The table below shows what levels of insulation are cost effective for different climates and. Open cell foam insulation values r3 r4. 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.

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. All these have r values ranging from r 3 2 to r 3 8 per inch. The r value is r 3 5 to r 3 6 per inch so filling a 2 4 cavity yields about an r 13. 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.

However there are open cell spray foam insulation products actually offer r 3 7 per inch such as icynene classic and. In comparison an inch of blown fiberglass insulation has an r value of 3 1 3 4 and. The r value of some insulations also depends on temperature aging and moisture accumulation. Insulation level are specified by r value.

Focusing on spray foam insulation materials there is a difference between the two main types. For example closed cell spray foam depending on brand can offer an r 6 or r 7 per inch. The r value of spray foam insulation is approximately 6 per inch so those using spray foam as their insulator will need about 6 3 inches of thickness to reach r 38.