Concrete floor seepage occurs primarily when there is a large amount of hydrostatic pressure beneath the floor of your home. Continue reading to learn how to stop concrete floor seepage and how to keep a basement or concrete floor dry.

What causes concrete floor seepage?

When it rains, water is absorbed into the ground until the earth is too saturated to soak up any more water. At this point, the water will begin to rise to the surface, causing hydrostatic pressure to build up against your foundation and basement floors, which leads directly to water seepage into your home.

How to fix concrete floor seepage:

  1. In order to fix concrete floor seepage, you must first locate where the water is coming from; the floor, a cold seam or a crack. You also need to determine the amount of moisture in the concrete by performing a calcium chloride test.
  2. Once you've discovered the source of the leak, you need to repair any cracks with a concrete crack repair kit and seal the cold seam with a cold seam sealant.
  3. Lastly, seal the floor with a waterproofing concrete floor sealer. The type of waterproofing concrete sealer can be determined by the results of the calcium chloride test.

In order to determine the moisture vapor emission rate of your concrete perform a calcium chloride test. To perform the test, a small amount of calcium chloride (salt) is placed under plastic on a clean piece of concrete. The calcium chloride (salt) absorbs the moisture coming from the concrete slab over a period of about 72 hours. The weight gain of the calcium chloride is then measured and the moisture vapor emission rate MVER is calculated. If a high amount of moisture is present in the concrete (over 3 lb according to a calcium chloride test) it is best to use a moisture vapor barrier coating. If the moisture content of the concrete is less than 4% you can use a penetrating concrete waterproofing sealer.

A calcium chloride test can be purchased directly through Amazon for about 18 USD.

If a high amount of moisture is present in the concrete, the Vapor-Tek 440 is one of the best moisture vapor barrier coating products on the market to reduce moisture vapor transmission. The high performance and quick installation features of this system make it an ideal solution to seal concrete from all water and moisture before installing carpet and wood or vinyl flooring. The Vapor-Tek 440 will reduce moisture vapor emission rates of up to 20lb. / 24 hr / 1,000 ft. prior to the application of flooring. It will also stop moisture from coming up through the slab to stop concrete floor seepage.

Alternatively, if your concrete has never had a moisture or dampness problem and you are looking for a preventative, cost-effective solution, use the Lithi-Tek 9500. This all-in-one product will reduce the porosity of the concrete making it less permeable to moisture. Althought it will not prevent a large amount of moisture from coming up through the concrete like the Vapor-Tek 440, it is an effective solution to reduce porosity.

9500 Concrete Sealer Bottle

Lithi-Tek 9500


440 Concrete Sealer Bottle

Vapor-Tek 440

Vapor Barrier Coating

Published Tuesday 31st of May 2022 // Updated Tuesday 30th of March 2021

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