Open Cell Insulation Vapor Barrier

One manufacturer demilec says its heatlok high lift spray foam has an even higher r value r 7 5 per in closed cell foam is much denser about 2 lb.

Open cell insulation vapor barrier.

Vapor barriers sheets of plastic or kraft paper keep water vapor out of the wall cavity so the insulation stays dry. But if it does the barrier should face inside in northern heating climates and outside in humid southern climates. R value at 1 3 7. When an area is accessible for maintenance or repair then any foam must have an ignition barrier over the foam or an equivalent material such as properly tested and listed intumescent coating matched to the type and brand of foam or it must be.

Scientists still discuss if those methods are efficient. So if you re considering spraying foam to the roof deck of your new or existing home you want open cell. Closed cell foam insulation is non porous with all of the voids closed to each other which makes it difficult for water vapor and air to pass through it. Many of them don t agree that vapor barriers are so necessary even with open cell foam insulation.

Open cell spray foam is not a moisture vapor barrier and will allow moisture to pass. Foam insulation porosity vapor barrier issue. Not every type of insulation needs a vapor barrier. For example closed cell foam is from class ii and open cell is from class iii.

Open cell spray foam closed cell spray foam. In most applications the buildings energy performance will be the same regardless whether you used open or closed cell foam. Spray in insulation and air barrier material. Structural reinforcement able to deflect water and reject bulk water able to accommodate seasonal shifting.

Vapor barrier vapor permeability. But if foam is open cell that barrier must be applied. Open cell needs a class ii vapor retarder old term barrier only in certain climates not all. There are three classes of vapor barriers.

Ft and it s unaffected by water. Closed cell foam has a much higher r value than open cell foam about r 6 5 per inch and it s a vapor barrier as well as an air barrier. After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. If there s a roof leak water will pass through the foam and you will quickly be able to find your problem.

Not every wall does.