Spray Foam Insulation Thickness R Value

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.

Spray foam insulation thickness r value.

Closed cell spray foam r values. Recommended home insulation r values. 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. All these have r values ranging from r 3 2 to r 3 8 per inch.

The r value depends on the type of insulation its thickness and its density. Focusing on spray foam insulation materials there is a difference between the two main types. 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. 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.

In comparison an inch of blown fiberglass insulation has an r value of 3 1 3 4 and. 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. 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. These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation.

The table below shows what levels of insulation are cost effective for different climates and. The common denominator among varieties of insulation is the 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. R value is a measure of insulation s ability to resist heat traveling through it.

R value is a measurement of thermal resistance and measures the ability of heat to transfer from one side of an object to another. For example closed cell spray foam depending on brand can offer an r 6 or r 7 per inch. The r value of some insulations also depends on temperature aging and moisture accumulation. Open cell foam insulation values r3 r4.

Closed cell spray foam insulation. As a benchmark one inch of solid wood has an r value of 1. When calculating the r value of a multilayered installation add the r values of the individual layers. Insulation level are specified by r value.

However there are open cell spray foam insulation products actually offer r 3 7 per inch such as icynene classic and. 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. The r value is r 3 5 to r 3 6 per inch so filling a 2 4 cavity yields about an r 13.