How To Install Vapor Barrier On Concrete Walls

The water vapor can come through the concrete from the soil or from indoor air that comes in contact with the concrete.

How to install vapor barrier on concrete walls.

Vapor barriers are a way to keep moisture from getting into the concrete. Of rigid moisture proof insulation. Finish the wall within a month of installing the barrier to prevent damage to the surface and protect the vapor barrier. We used thermax brand available through lumberyards of polyethylene vapor barrier because it doesn t require an additional fire barrier.

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. Cover exposed foundation walls with 1 1 2 in. With fiber insulation and a vapor barrier moisture can get trapped in the insulation leading to moldy insulation and decay in the wood framing. Find out where to buy vapor barriers and other problem solving products.

Also be sure to use treated lumber for the bottom plate on the wall framing. Astm e 1643 standard practice for installation of vapor retarders used in contact with earth or granular fill under concrete slabs provides details but here are a few tips. Follow the instructions on the tsp when measuring ratios of water to tsp. In any case the vapor barrier must point to the warm side.

To be extra certain use a caulk gun to place caulk material around the tape to double seal the barrier. To clean the wall mix up a dilution of water and trisodium phosphate or tsp in a bucket. Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets. To be effective a vapor barrier must be installed in a way that prevents any water vapor from getting to the slab.

Using other kinds of tape will compromise the waterproof seal and render the barrier useless. In this video you ll learn how to install a proper poly moisture vapor barrier against your block basement wall before finishing and closing up your wall sec. This is why a vapor barrier under concrete is essential. The science of moisture movement.

Before attaching the vapor barrier to the wall it is essential that you wash the concrete to remove substances such as mold grease or sand. A vapor barrier is not the same as an underlayment. If you have a concrete floor that s in continuous contact with a source of moisture you re going to have problems. The problem is that moisture tends to condense on the cool concrete walls.

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.