Water is a key component of a concrete mix. The hydration reaction that takes place between cementitious materials and water is vital for the development of the full strength of the concrete. However, excess moisture in a concrete slab after curing can cause problems with the performance of flooring systems unless suitable preparation measures are undertaken prior to application of the flooring. Whether the excess moisture exists due to rising damp coming through a ground slab or because a concrete floor has not been given sufficient time to dry, excess moisture can lead to flooring failures, litigation, expensive remedial work, and disruption to commercial operations.
How can moisture cause problems in concrete floors?
If given sufficient time and suitable conditions, excess moisture will evaporate from a well-cured concrete slab so that it is dry enough for the installation of floor coverings. However, the project may be under time pressure, weather conditions, and humidity may have slowed down the evaporation of moisture from the concrete, or, in the case of a ground slab, a failed vapour barrier may be allowing rising damp to occur. If a flooring system is placed over a concrete floor whose moisture content exceeds the flooring manufacturer's recommendations, problems can be expected to occur over time, such as:
- Delamination of the floor covering
- Cracking and bubbling of coverings and coatings
- Uneven floor surfaces
- Unsightly efflorescence in cementitious grout
- Mold growing on the underside of the flooring
To cover the risk of a floor system failure, clients will require the floor installer to supply a warranty stating that the work has been carried out in accordance with the manufacturer’s specifications. The best way to prevent such problems and ensure the long-term high performance of the flooring system is for the flooring contractor to comply with the recommended test method and apply a damp-proof membrane that is appropriate for the slab’s measured moisture content.
HYTEC Solutions: Protect your concrete floors from moisture
To give a flooring system the optimum likelihood of long-term successful performance, newly poured concrete should be allowed to cure for the specified time and the slab protected and allowed to dry for as long as possible to minimize the residual moisture content. Prior to the application of the flooring system, the moisture content of the concrete should then be tested using the method specified by the manufacturer (e.g. Calcium Carbide Method [%CM], Probe Method [%RH], VI-D4 Romus [%CM or %RH]) to confirm that the moisture levels are below the limits of the materials to be applied. Note that conditions such as groundwater, temperature, and weather can affect moisture content readings and that the moisture measurement gives only a snapshot at the time of the test.
Control Moisture and Protect Your Floors
To avoid moisture-related problems with flooring systems, it is important to implement best-practice methods by carrying out moisture testing and applying fit-for-purpose damp-proof membranes to the substrate. Bostik’s HYTEC suite of damp-proof membrane solutions presents a range of measures suitable for the varying conditions that can occur on new-build and renovation projects.
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Long-term protection of flooring against concrete moisture equals peace of mind
Effective subfloor preparation ensures the highest-quality floor finishes and allows high-spec materials to live up to their potential. Installing floors protected with one of Bostik’s state-of-the-art HYTEC damp-proof membrane solutions will provide peace of mind for installers and allow them to sign their warranties with confidence. An HYTEC solution will give the client a flooring system with proven long-term protection from the disruption, annoyance, and costs that can arise from moisture-related problems.
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