Moisture Barrier Against Concrete Wall

Most jurisdictions require a 4 mil plastic sheet vapor barrier for basement walls against concrete.

Moisture barrier against concrete wall.

A vapor barrier against the concrete surface is generally recommended before wood framing or flooring materials are installed. The water vapor can come through the concrete from the soil or from indoor air that comes in contact with the concrete. Holes in the vapor barrier that allow humid air through may allow a lot more water vapor into an assembly than the vapor barrier is stopping. Below grade walls and floor slabs transmit ground moisture through concrete walls or slabs.

Not to be confused with a vapor barrier which is placed on the warm side of the wall just in front of the insulation and behind the drywall a moisture barrier goes against the basement wall. In any case the vapor barrier must point to the warm side. Crawl spaces benefit from a polyethylene moisture barrier placed directly over the exposed earth. Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets.

Sole plates or sill plates are the first pieces of framing lumber placed in home construction. These plates must be made of pressure. Moisture barrier between the sole plate the concrete slab. With fiber insulation and a vapor barrier moisture can get trapped in the insulation leading to moldy insulation and decay in the wood framing.

When a vapor barrier is on the side of a wall where the dry air is i e outside in winter or inside in summer moisture problems can occur. This will give you two vapor barriers one before and one after the stud wall framing. Actually a concrete wall or a masonry wall without cracks is in itself a very good air barrier. This is a water infiltration barrier and perhaps an air barrier.

Of foam against the wall this should not be a problem in your climate. The other option is to set the 2 4 wall framing in 4 from the masonry or concrete basement walls and use just the vapor barrier on the insulation facing toward the living space. A vapor barrier reduces the movement of water vapor by diffusion. This material adapts to let moisture out of the wall whether.

If you have a double brick wall in the above ground portion of the house we will often find some kind of building paper against the brick inside the house. A smart vapor retarder is able to adapt its permeability to allow the wall to dry should moisture get trapped in the wall cavity. That is if the studs are going to touch the concrete wall. A smart vapor retarder is a vapor retarder material with the unique ability to react to changes in relative humidity by altering its physical structure.