Spray Foam R Values

Spray foam creates a thermal barrier to heat because it is not easily transferred through.

Spray foam r values.

A typical 2 4 stud filled with open cell spray foam will have an r value between 10 5 and 14. During the late 1970s the ftc. In these cells there is a low conductivity gas that shields the house from losing warm or cool air. The r value of some insulations also depends on temperature aging and moisture accumulation.

Insulation that fills building cavities densely enough to reduce airflow can also reduce convective heat loss. Open cell spray foam has an r value of about r 3 7 per inch while closed cell spray foam has an r value that may be as high as r 6 5 per inch. Spray foam insulation is labeled has air impermeable insulation and does not have the r values as traditional 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.

The highest r value can be found in closed cell polyurethane spray foam. 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. It has a lower r value per inch than closed cell foam and is vapor permeable. This type of spray foam is used in buildings and houses.

Closed cell spray foam 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. Icynene sprayed in foam is an insulation and air seal system that works to help ensure that your home doesn t suffer from air loss while providing an effective r value. Installing more insulation in your home increases the r value and the resistance to heat flow.

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. If you want to install spray foam in a stud wall and price is no object then it would seem to make sense to specify closed cell spray foam right. Closed cell spray foam r values. 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.

Open cell spray foam has an r value of 3 5 per inch. The r value of this foam per inch ranges from r 5 to r 6. By expanding 100 times its original size icynene seals cracks and gaps in attics walls ceilings and other spaces where air might escape. 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 in place polyurethane is an absolute minimum of three to ten times as effective as any other insulation available today. When calculating the r value of a multilayered installation add the r values of the individual layers. Nor can you use the r value of a foam insulation if it is in sheet form and compare it to the r value of spray in place foam insulation.