How To Install Vapor Barrier On Concrete Walls

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.

How to install vapor barrier on concrete walls.

In any case the vapor barrier must point to the warm side. Vapor barriers are a way to keep moisture from getting into the concrete. We used thermax brand available through lumberyards of polyethylene vapor barrier because it doesn t require an additional fire barrier. The water vapor can come through the concrete from the soil or from indoor air that comes in contact with the concrete.

The science of moisture movement. The problem is that moisture tends to condense on the cool concrete walls. This is why a vapor barrier under concrete is essential. To be extra certain use a caulk gun to place caulk material around the tape to double seal the barrier.

Using other kinds of tape will compromise the waterproof seal and render the barrier useless. To clean the wall mix up a dilution of water and trisodium phosphate or tsp in a bucket. With fiber insulation and a vapor barrier moisture can get trapped in the insulation leading to moldy insulation and decay in the wood framing. 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.

Find out where to buy vapor barriers and other problem solving products. Thus installing vapor barriers on wall surfaces must. 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. Finish the wall within a month of installing the barrier to prevent damage to the surface and protect the vapor barrier.

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. This not only insulates the walls but also keeps rising dampness in the concrete from getting into the crawlspace. Of rigid moisture proof insulation. If you have a concrete floor that s in continuous contact with a source of moisture you re going to have problems.

To be effective a vapor barrier must be installed in a way that prevents any water vapor from getting to the slab. Water vapor can pass through building materials in several ways including direct transmission and by heat transfer but studies suggest that fully 98 percent of the moisture transfer through walls occurs through air gaps including cracks around electrical fixtures and outlets and gaps along baseboards. Follow the instructions on the tsp when measuring ratios of water to tsp. Also be sure to use treated lumber for the bottom plate on the wall framing.

Cover exposed foundation walls with 1 1 2 in.