Closed Cell Attic Foam

But open cell spray foam with a vapor retarder can work too.

Closed cell attic foam. Closed cell foam can also add to the structural strength of the roof system which can make it a more appealing choice in locations that frequently endure high winds. In a vented attic all of that expensive airflow is lost to the environment. Closed cell foam can also increase the racking strength of attic walls which. Closed cell closed cell is a two component medium density one to one by volume spray applied polyurethane foam.

Many builders in cold climates use closed cell spray foam instead because of its lower water vapor permeability which means it doesn t need the extra step of installing a vapor retarder. Closed cell foam can be over three times that with a density of 1 75 pounds per cubic foot or more. But some closed cell foams like tiger foam s e84 closed cell formula have even higher ratings that go up to almost 7 per inch. The problem that can occur in a closed attic assembly is the management of the moisture that rises and accumulates in the attic space.

This is very important in situations where your code requires an r 21 for the wall but you only have a 2 4 stud because closed cell spray foam is the only way you would achieve the required r value to meet code. Open cell foam weighs 1 2 pound per cubic foot and closed cell weighs 2 lbs per cubic foot. I have open cell in my house since 2004 and i would not use it in a dogs out house. This medium density spray foam is a closed cell spray foam that is typically used where there is the need for r value insulation per inch possible.

When we seal the attic with spray foam it s as tight as a butter tub. Open cell foam has an r value of about 3 5 to 3 7 per inch while closed cell foam has an r value of about 6 per inch. One huge benefit of the spray foam insulated attic is that conditioned air leakage from the ac furnace duct system is contained and used to condition the attic. This type of spray foam offers the specific benefits of continuous insulation interior wall cavity fill and unvented attic applications.

To produce closed cell requires the use of an a component iso and a blended b component resin which contains zero ozone depleting blowing agents catalysts polyols and fire retarding materials. 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. You see hot moist air rises the peak of the attic is the highest point and vapor drive moves from warm to cold. Closed cell foam has a higher r value than open cell foam usually about 6 0 per inch.

A foams r value is its resistance to heat flow or in other words how well they insulate.