Foil Faced Batt Insulation Vapor Barrier

A common practice with foil faced insulation.

Foil faced batt insulation vapor barrier.

This is especially true if you do not staple the facings to the front of the studs but instead either just press the insulation into place or staple it on the inside of the stud. Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets. Vapor barrier fiberglass insulation batts depending on the space to be insulated you can select paper faced foil faced or loose batts. As mentioned earlier batt and roll insulation come with a vapor barrier attached.

Measure the roll or batt of insulation to the area that you are going to install it in. If it is too big then trim it to size. Remember to set the paper faced insulation upwards. Foil faced 75 150.

This barrier is meant to keep moisture from getting to the insulation in the walls and ceilings and it is required by building codes when insulating most houses. Water vapor sorption by weight astm c1104 5. For many building science questions the answer is it depends for this one the answer is clear. Water vapor permeance perms astm e96 kraft faced 1 0.

Type 2 vapor barriers the basic vapor barrier for ordinary conditions are defined as having a permeance less than or equal to 60 ng pa s m 2 of moisture passage. Installing insulation has almost the same steps for all. If you install fiberglass batt insulation with a kraft paper vapor retarder in a home which way do you face the vapor retarder. These barriers are required where there is cladding on the house that doesn t allow enough drying to the outside.

Prevalent vapor barrier materials used over the years have been polyethylene type 1 asphalt impregnated or asphalt coated kraft paper type 2 and foil skrim kraft fsk type 1 paper backed aluminum. To the inside of the home or the outside of the home. When you want to retard the movement of moisture from one place to another you need some form of impervious barrier. This is the reason you need not add a vapor barrier when you are using paper faced insulation.

However leakage can occur where the facings meet. Critical radiant flux w cm 2 astm e970 0 12. Avoidance of the installation of vapor barriers such as polyethylene vapor barriers foil faced batt insulation and reflective radiant barrier foil insulation on the interior of air conditioned assemblies a practice that has been linked with moldy buildings lstiburek 2002. In any case the vapor barrier must point to the warm side.