Plastic Over Batt Insulation

This attic had R13 Batt insulation installed backwards with plastic above the insulation. Does this not create a potential moisture problem between the ceiling joists.

Yes it does.

Sure does

With your location in Alabama, the vapor barrier may not be installed “backwards”.



Vapor Retarders in Warm Climate Zones 1, 2, 3, and 4

The IRC does not require or prohibit the use of vapor retarders in climate zones 1, 2, 3, and 4. NAIMA recommends using either a Class II or III vapor retarder in these warmer climate zones and avoid the use of Class I (very low perm) vapor retarders. Kraft-faced batts can be installed in all climate zones.

In the warmer climate zones, installing vapor retarder with a very low perm rating on the interior of a wall assembly can lead to moisture problems. Even vinyl wall paper, which has a low perm rating, can induce moisture problems in warm, humid climates where hot, moist conditions tend to drive moisture into the wall from the outside of the building.

In very warm, humid climates, if a vapor retarder is used, NAIMA recommends installing it to the exterior side of the wall.
Climate Zones

NAIMA has developed a map showing thermal recommended levels of insulation for various climate zones. They are based on recommendations from the U.S. Department of Energy (DOE) and the International Energy Conservation Code (IECC). The IECC is the model building code for the United States. To learn more about recommended levels of insulation, click here.

I agree isn’t Alabama really humid? I don’t like to see double vapor barrier though. I would like to see the insulation pulled back and see if there is any signs of moisture under the the insulation.