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 foam r value chart.
Closed cell spray foam insulation.
Polyurethane and polyisocyanurate are both closed cell foams.
Along with knowing the r value of a particular insulation it is also important to calculate the r value of a total system.
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.
Closed cell foam r6 r8.
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.
Both closed cell spray foam and open cell spray foam insulation can be used effectively in commercial building designs to allow the building to achieve energy efficiency and consistent performance.
It has a lower r value per inch than closed cell foam and is vapor permeable.
It demonstrates the calculation method and does a good job of estimating the incremental r value attributable to an upgrade from open cell to closed cell foam.
The r value for closed cell is typically around 6 7 at 1 thick and varies by manufacturer.
While it s true that actual whole wall r values will usually be higher than the values shown in the table due to the r values of the sheathing drywall.
The r value is r 3 5 to r 3 6 per inch so filling a 2 4 cavity yields about an r 13.
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.
Closed cell spray foam r values.
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.
As a benchmark one inch of solid wood has an r value of 1.
For 6 inches r 15 or r 19 etc.
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.
That said the table is useful.
Just like for open cell foam r values are additive.
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.
Note that some commercial and industrial buildings may require higher r values.
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.
Closed cell spray foams are between 2 and 4 lbs.
Two inches of closed cell foam will provide r12 r14 of insulation.