Two inches of closed cell foam will provide r12 r14 of insulation.
Open cell polyurethane foam r value.
Polyurethane and polyisocyanurate are both closed cell foams.
Open cell spray foam r values.
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.
They contain low conductivity gases in the cells usually one of the hcfc or cfc gases the higher r values r 7 0 to 8 0 are the result of thermal resistance of the gases in the cells.
Just like for open cell foam r values are additive.
By expanding 100 times its original size icynene seals cracks and gaps in attics walls ceilings and other spaces where air might escape.
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.
They sport an r value of 6 0 8 0 per inch of insulation about double their open cell foam counterparts.
Closed cell spray foams are between 2 and 4 lbs.
Closed cell spray foam insulation 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 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.