Open Cell Foam Insulation In Attic

The myth that open cell is more economical is bullshit.

Open cell foam insulation in attic.

Closed cell foam will act as a vapor barrier when installed to a depth of at least 2 while open cell foam won t act like a vapor barrier at any depth. Most insulation contractors are recommending open because it s cheaper and also because if i go with closed cell and the roof leaks it will not penetrate the insulation and could remain stuck between the sheathing and the insulation and could rot the wood and or travel to a more hidden spot of the roof or attic causing worse problems that are harder to notice than if the roof leaked and water penetrated through the open cell which i would be able to see and fix if necessary. The open cell polyurethane foam has an r value of 3 5 to 3 6 per inch with a price tag of 1 1 20 square foot. 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.

Do it right and your roof will not rot. Open cell foam weighs 1 2 pound per cubic foot and closed cell weighs 2 lbs per cubic foot. Open cell foam insulation in attics the basic difference. Closed cell spray foam exterior applications.

The minimal layer applied to individual attic elements should have approx. An open cell type of foam is mainly used in attics due to its price. This spray foam is applied as a low or high pressure two component polyurethane spray foam that can be applied onto walls in unvented attics to ducts and ceilings and in vented attics and crawl spaces. To be labeled as open cell foam more than half of the cells must be open which means the bubbles.

For bigger jobs such as roof attic floor and wall insulation you will need professional help and equipment. Insulating value and strength. 20 cm usually it s 18 cm. Lstiburek says to do it for every spray foam attic.

Others like david butler see his comment below say you need to do it only if a moisture problem develops. When applied on the interior open cell spray insulation provides performance advantages that differ from those of closed cell spray foam used on the exterior. It is worth remembering the insulation thickness depends on many factors like design assumptions or the expected insulation efficiency. 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.

Open cell spray foam is a perfectly acceptable insulation product to use in attics. Open cell foam has an r value of about 3 5 to 3 7 per inch while closed cell foam has an. An open cell foam low density spray polyurethane is a spray applied to provide continuous insulation and an air sealing barrier. There you have it.

Diyers can use this foam for small jobs such as insulating door frames.