R Value Of Polyurethane Foam Per Inch

The r value of closed cell foam is r 6 5 7 per inch.

R value of polyurethane foam per inch. Case studies during the 1970s in idaho s snake river valley my firm insulated the walls of many new homes with 1 25 inches of spray in place polyurethane foam. That means if you used foam it green closed cell which is r 7 per inch it s r value for a 3 5 deep wall cavity would be r 24 5. 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. These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation.

This product typically has an r value of 3 6 to 4 0 per inch of thickness. All these have r values ranging from r 3 2 to r 3 8 per inch. Expanded polystyrene insulation is similar to the foam used for packing peanuts and it s typically used for insulated concrete forms also knows as icf s. 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.

Using this value we were putting an r of 1 25 x 9 09 11 36 in the walls. Closed cell spray foam insulation. For example closed cell spray foam depending on brand can offer an r 6 or r 7 per inch. 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.