Spray On Moisture Barrier Foam Insulation

If there s a roof leak water will pass through the foam and you will quickly be able to find your problem.

Spray on moisture barrier foam insulation.

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. If a home has spray foam insulation in an attic or crawl space the building code requires using materials or assemblies that offer some fire resistance but not as much as is required for a thermal barrier. They are combined with flashing and other materials to ensure that there is a shingled assembly to direct liquid water. Many of them don t agree that vapor barriers are so necessary even with open cell foam insulation.

Moisture barriers should be installed on the cold side of the insulation. Open cell spray foam is not a moisture vapor barrier and will allow moisture to pass. Its spray applied installation process speeds construction and reduces labor costs substantially estimated up to 1 square foot. There are three classes of vapor barriers.

Offering up to 50 more energy saving compare to conventional insulation has made foam insulation the favorite for both eco conscious customers and also the ones who desire to save more money on energy bills in longer period. The chemicals being sprayed these days only require one inch of foam. So if you re considering spraying foam to the roof deck of your new or existing home you want open cell. Closed cell spray foam limitations.

Vapor barrier unlike other insulation systems closed cell spray foam will create a vapor barrier if sprayed at a certain thickness. 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. Ccspf is a great air and vapor barrier but it is not effective at sealing liquid water leaks. Scientists still discuss if those methods are efficient.

Foam was required before qualifying as a vapor barrier. The sources and causes of the water need to be corrected before the spray foam is installed. For some manufacturers the foam is required to be at least 2 5 thick to qualify as a vapor barrier. Of note the thickness required is product specific.

For example closed cell foam is from class ii and open cell is from class iii. Ft and it s unaffected by water. If you ve got spray foam insulation in an attic for example it s probably already separated from the living space by a thermal barrier. Moisture barriers are specifically designed not to be a vapor barrier as the minimum water vapor permeance for a water resistive barrier is 300 perms.

Years ago approximately 2 1 2 inches of 2 lb. But if foam is open cell that barrier must be applied. Closed cell spray foam can be a vapor barrier after it is installed at least 1 5 thick. Spray foam is used as thermal barrier air barrier moisture resistant and in some cases as sound proofing product.