How To Install Vapor Barrier On Concrete Walls

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.

How to install vapor barrier on 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. If you have a concrete floor that s in continuous contact with a source of moisture you re going to have problems. This is why a vapor barrier under concrete is essential. 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.

We used thermax brand available through lumberyards of polyethylene vapor barrier because it doesn t require an additional fire 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. Follow the instructions on the tsp when measuring ratios of water to tsp. Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets.

This not only insulates the walls but also keeps rising dampness in the concrete from getting into the crawlspace. A vapor barrier is not the same as an underlayment. To clean the wall mix up a dilution of water and trisodium phosphate or tsp in a bucket. Also be sure to use treated lumber for the bottom plate on the wall framing.

With fiber insulation and a vapor barrier moisture can get trapped in the insulation leading to moldy insulation and decay in the wood framing. Using other kinds of tape will compromise the waterproof seal and render the barrier useless. To be extra certain use a caulk gun to place caulk material around the tape to double seal the barrier. Finish the wall within a month of installing the barrier to prevent damage to the surface and protect the vapor barrier.

Thus installing vapor barriers on wall surfaces must. Of rigid moisture proof insulation. The science of moisture movement. Cover exposed foundation walls with 1 1 2 in.

To be effective a vapor barrier must be installed in a way that prevents any water vapor from getting to the slab. 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. The problem is that moisture tends to condense on the cool concrete walls. In any case the vapor barrier must point to the warm side.

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