Open Or Closed Cell Foam For Attic

It s expanding properties ensure that it covers every little crack and hole but even with that ability it still needs to be installed correctly.

Open or closed cell foam for attic.

Because of this closed cell foam is much more rigid and stable than open cell foam. It s just a pathway. Spray foam insulation is broken down into two categories open and closed cells. Closed cell insulation can break apart existing structures due to its strength and expansion.

Light density open cell spray foam is commonly known as half pound foam that is a semi rigid material with a sponge like appearance. This material will begin to expand after installation and it will form small openings open cells that are filled with carbon dioxide. The myth that open cell is more economical is bullshit. The role of open cell spray foam.

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. The evaluation service report esr for spray foam insulation products provides a valuable resource based on a third party review of testing information useful for utilizing these products successfully and according to code requirements. This describes the way that the foam looks once solidified. It has a relatively high vapor permeance 3 perms at a thickness of 6 allowing water vapor to migrate to the roof decking at night and back into the attic air in the daytime.

Open cell foam weighs 1 2 pound per cubic foot and closed cell weighs 2 lbs per cubic foot. Open cell vs closed cell. Most open cell foam has a density of about 5 pounds per cubic foot. Open cell has an r value of 3 7 and closed cell has an r value of 6 5 based per inch of installed spray foam.

Open cell is created through lower pressure and as a result has a more open structure. Both low density open cell and medium density closed cell spray foam can be used in an unvented attic to provide the needed thermal resistance and airtightness. Closed cell foam is much denser than open cell foam. 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.

It s the wood decking that stores the moisture though. The cells are pressed together so air and mositure are unable to get inside the foam. Open cell spray foam insulation doesn t store the moisture. Closed cell foam can also increase the racking strength of attic walls which.