Moisture Barrier Between Wood And Concrete

Sole plates or sill plates are the first pieces of framing lumber placed in home construction.

Moisture barrier between wood and concrete.

Concrete may seem very dense but it is actually full of small pores that will absorb water from the ground. Most commercial specs for building forbid non treated wood in direct contact with concrete. Perminator vapor barriers help reduce the penetration of moisture and water vapor through the slab and into the building which helps reduce mold fungus and mildew. Perminator also helps reduce radon gases from entering a building through.

Crawl spaces benefit from a polyethylene moisture barrier placed directly over the exposed earth. So there is enough gap for air to flow. Meadows makes a concrete vapor barrier called perminator. When installing certain types of flooring such as sheet vinyl the moisture content of the concrete can be a problem.

Without the proper moisture barrier vinyl flooring acts as a moisture barrier causing it to buckle bubble and lift. The difficulty of course is that if the moisture barrier is compromised in any way moisture from the slab beneath can still damage the flooring or finish. Vapor barriers have been associated with certain concrete slab on grade problems including curling and cracking. Most jurisdictions require a 4 mil plastic sheet vapor barrier for basement walls against concrete.

Moisture barrier between the sole plate the concrete slab. Below grade walls and floor slabs transmit ground moisture through concrete walls or slabs. After concrete s initial cure when it is expelling it s water content and shrinking it then acts like a sponge and absorbs moisture. It is better to require some sort of phsyical barrier between concrete and wood treated or not treated.

During the replacement i attempted to reduce the moisture transference into the wood by installing some tar paper to act as a vapor barrier between the wood and the concrete slab. Apparently i may have made worse because we just had to replace the sub flooring again here within the last month. A vapor barrier should be used for all concrete floors and slabs that are going to receive an impermeable floor finish like epoxy laminate linoleum and wood or if the concrete floor will be used for any purpose where the passage of water vapor through the floor may create problems. Or you can leave a 4 inch gap between the studs and concrete wall and probably get away with it.

A vapor barrier against the concrete surface is generally recommended before wood framing or flooring materials are installed. That is if the studs are going to touch the concrete wall. But they have also proven to be beneficial in reducing failures of moisture sensitive flooring materials adhesives and coatings caused by excessive emission of moisture vapor from concrete slabs.