Polyethylene Vapor Barrier Attic

Adding a second vapor barrier could cause condensation to become trapped in the insulation between the two vapor barriers.

Polyethylene vapor barrier attic.

Attic vapor barrier detail for cold climates. Even though we apply vapor barriers to exterior insulated walls in cold climates it s no longer recommended for ceilings floor of the attic. If you re in maine and never use an air conditioner a vapor barrier on the inner surface may be ok. In any case the vapor barrier must point to the warm side.

Tips for installing vapor barriers. A plastic vapor barrier is best installed in a vented attic within climates with over 8 000 heating degree days. Because it s nearly impossible to seal penetrations in the ceiling the reality is water vapor will get into the attic. Crawl spaces benefit from a polyethylene moisture barrier placed directly over the exposed earth.

Condensation occurs whenever warm air meets cold air. If you re in a cold climate however and do use air conditioning you need to be careful with interior vapor barriers like polyethylene. Without a vapor barrier in place condensation inside the walls could ruin the. 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.

Plastic vapor barriers should only be installed in vented attics in climates with more than 8 000 heating degree days. This same process occurs inside the walls of your home. 1 16 of 726 results for polyethylene vapor barrier 1000 sqft 4x250 solid white vapor barrier attic foil white radiant barrier reflective solid insulation 4x250ft non perforated woven polyethylene scrim heavy duty. 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.

You could be creating the kind of problems i described in scenario 1 above. A vapor barrier against the concrete surface is generally recommended before wood framing or flooring materials are installed. Attic insulation should always be installed with the paper backing facing toward the living space the ceiling in this case. This acts as a barrier to keep heated moist air from rising up into the attic during cold weather.

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