Spray Foam R Value Chart

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.

Spray foam r value chart.

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 example closed cell spray foam depending on brand can offer an r 6 or r 7 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. Use the following chart to estimate an ideal r value for your insulation project.

As a benchmark one inch of solid wood has an r value of 1. 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. Closed cell spray foam insulation. A typical 2 4 stud filled with open cell spray foam will have an r value between 10 5 and 14.

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. The r value is r 3 5 to r 3 6 per inch so filling a 2 4 cavity yields about an r 13. For 6 inches r 15 or r 19 etc. 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.

As always should you have any questions or require any assistance in planning your spray foam insulation job please contact us we are always happy to help. The r value for closed cell is typically around 6 7 at 1 thick and varies by. 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. The r value for open cell is typically around 3 7 at 1 thick and varies by manufacture.

Closed cell spray foam insulation is vapor and air impermeable and is applied with a minimum of 2 on average with use on on interior and exterior building applications. Closed cell spray foam insulation. The r value of some insulations also depends on temperature aging and moisture accumulation. When calculating the r value of a multilayered installation add the r values of the individual layers.

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. 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. Along with knowing the r value of a particular insulation it is also important to calculate the r value of a total system.

All these have r values ranging from r 3 2 to r 3 8 per inch.