Polyethylene Vapor Barrier Attic

In any case the vapor barrier must point to the warm side.

Polyethylene vapor barrier attic.

Plastic vapor barriers should only be installed in vented attics in climates with more than 8 000 heating degree days. Plastic vapor barrier in attic prior to blown insulation i am going to blow insulation into my attic and noticed one video where the people put down plastic over the floor studs as a vapor barrier prior to blowing the insulation. Tips for installing vapor barriers. 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.

A vapor barrier against the concrete surface is generally recommended before wood framing or flooring materials are installed. This acts as a barrier to keep heated moist air from rising up into the attic during cold weather. Attic insulation should always be installed with the paper backing facing toward the living space the ceiling in this case. Because it s nearly impossible to seal penetrations in the ceiling the reality is water vapor will get into the attic.

If you re in maine and never use an air conditioner a vapor barrier on the inner surface may be ok. You could be creating the kind of problems i described in scenario 1 above. This same process occurs inside the walls of your home. Attic vapor barrier detail for cold climates.

If you re in a cold climate however and do use air conditioning you need to be careful with interior vapor barriers like polyethylene. Even though we apply vapor barriers to exterior insulated walls in cold climates it s no longer recommended for ceilings floor of the attic. A plastic vapor barrier is best installed in a vented attic within climates with over 8 000 heating degree days. Adding a second vapor barrier could cause condensation to become trapped in the insulation between the two vapor barriers.

Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets. Without a vapor barrier in place condensation inside the walls could ruin the. You can forego the plastic and use a vapor retarder kraft faced insulation or latex ceiling paint in all other climates except hot humid or hot dry climates. 4 8 out of 5 stars 14.

Condensation occurs whenever warm air meets cold air.