Foam R Value

Closed cell spray foam insulation.

Foam r value.

For example closed cell spray foam depending on brand can offer an r 6 or r 7 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. Because of this i often get questions about which type of foam board insulation to use and what r values these products provide. Additional r value for a masonry wall constructed using these materials needs to add the insulating value of additional wall components typically included such as 1 solid foam polyisocyanurate r 8 extruded polystyrene r 5 expanded polystyrene r 4 or 1 of perlite r 2 7 and for an exterior air film winter no wind r 0 17 an interior.

These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation. I ve written several posts about how to insulation basement walls in which i promote the use of foam board insulation as the first line of defense against moisture and mold. 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. Also called styrofoam insulation this is the least expensive material.

Foam board insulation types. Insulation level are specified by r value. For example a wall with 3 fiberglass batting r value of 10 8 11 9 may have an overall r value of nearly 14 because of siding sheathing and drywall. Recommended home insulation 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. Each type comes with unique advantages. The higher the r value the better the thermal performance of the insulation. It provides r values that range from 3 6 to 4 2 per inch.

During the late 1970s the ftc federal trade commission went after urethane foam. All these have r values ranging from r 3 2 to r 3 8 per inch. For 6 inches r 15 or r 19 etc. Closed cell spray foam r values.

R value is a measure of insulation s ability to resist heat traveling through it. Spray in place polyurethane is an absolute minimum of three to ten times as effective as any other insulation available today. Products with a higher r value have a higher cost but have an increased capacity to resist heat flow and therefore provide greater insulation. 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.

A typical 2 4 stud filled with open cell spray foam will have an r value between 10 5 and 14. There are three basic foam insulation board products on the.