Closed Cell Attic 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 attic foam.

We are going to address the idea of air exchange in closed attics that use open cell foam. Closed cell foam has a higher r value than open cell foam usually about 6 0 per inch. Open cell foam weighs 1 2 pound per cubic foot and closed cell weighs 2 lbs per cubic foot. 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.

There is 300 difference there but the cost they give you is about a third difference and open cell foam at 12 inches will not give you the performance of 2 inches of closed. A foams r value is its resistance to heat flow or in other words how well they insulate. This type of spray foam offers the specific benefits of continuous insulation interior wall cavity fill and unvented attic applications. But open cell spray foam with a vapor retarder can work too.

Closed cell foam can also increase the racking strength of attic walls which. 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. 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.

Closed cell foam can be over three times that with a density of 1 75 pounds per cubic foot or more. 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. 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 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.

Closed cell closed cell is a two component medium density one to one by volume spray applied polyurethane foam. Intumescent coatings are not always needed to coat spray foam in the attic in order to meet code thermal barrier requirements. When we seal the attic with spray foam it s as tight as a butter tub. 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.

I have open cell in my house since 2004 and i would not use it in a dogs out house.