Spray Foam Insulation R Value 2x4

Open cell spray foam typically has an r value of 3 5 per inch and it should be noted that open cell does not form a tight air seal.

Spray foam insulation r value 2x4. Our open cell foam product has an r value of 3 5 per inch and in most applications a house constructed with 2x4 studs will have 3 5 inches of open cell foam thus resulting in a total r value of 12. Code is all about sealing and insulating now. The r value is a calculation which measures the flow of heat through an insulation product or its. Ultimate spray foam insulation has a few different foam products of different densities.

To meet r 20 requirement if that is what code says in your location. Closed cell spray foam aka two pound foam is denser than open cell at about 2 pounds per cubic foot. Find your zone on the map and then use the above insulation r value chart to determine the level of insulation you need to properly insulate your attic walls floors and crawlspaces. Insulation is rated in two ways r value and u value.

Closed cell s obvious advantages compensate for its slightly higher price tag of 15 to 30 for the same thickness. In a 2x4 wall you can use spray foam but it has to be closed cell not open cell. But that carries it s own added cost. The installed insulation r value depends somewhat on the system manufacturer but generally speaking high density foam 2 0 pcf ranges between r 5 5 and r 6 5 per inch for the aged r value and low density foam 0 5pcf has an r value of approximately r 3 6 inch.

Closed cell foam is r 7 25 per inch. Two inches of closed cell foam will provide r12 r14 of insulation. They sport an r value of 6 0 8 0 per inch of insulation about double their open cell foam counterparts. Foam it green sprays on fast creating a seamless air and moisture barrier.

And with an r 7 per inch you get to r 21 in 3 inches of foam. Just like for open cell foam r values are additive. 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. How to achieve r 21 in a 2x4 wall.

Insulating a 2 4 wall with foam it green is the quickest and easiest way to meet code standards. Closed cell spray foams are between 2 and 4 lbs. 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.