What Causes Moisture Issues for Floor Coverings?
Moisture related failures are most often due to one or all of the following:
The moisture in the concrete slab has a higher emission rate than the floor covering can tolerate.
The concrete slab was not allowed to dry sufficiently before installing the floor covering over it.
No moisture testing was performed or it wasn’t done correctly.
The conditions in which the moisture test was initially done changed over time.
The alkalinity level is too high in the concrete slab due to a high moisture emission rate. High alkalinity levels destroy the bond between adhesive and floor covering.
What can happen to your flooring due to moisture issues?
Damage to floor coverings include debonded flooring, bubbling, blisters, discoloration, adhesive degradation or oozing. Cupping, dents, indentation, gaps between tile, the smell of adhesive coming from your floors and even mold are all also signs of a moisture issue. Without moisture correction precautions, the flooring could be destroyed completely.
Examples of flooring susceptible to sub-floor moisture:
Vinyl Composition Tile (VCT)
Unbacked Sheet Vinyl
Rubber Flooring
Carpet Tile
Vinyl Tile
Other non-breathable finished floors
There are many methods of correction depending on test results. Sometimes changing the product is enough, other times changing to high moisture adhesive works, and sometimes you need a full remediation system. What choice you make depends on application, product and levels of moisture.
Brief Guideline to Moisture Issue Remediation:
1) Moisture Testing
Remove current floor covering and perform flooring tests. The results from these tests will point you in the direction to correctly address any issues.
Types of tests include:
RH (Relative Humidity): Shows the available moisture in the slab in its final state.
Calcium Chloride: Shows the amount of moisture in the concrete at the surface.
Alkalinity Test: Measures the pH levels in your flooring.
2) Floor Prep and Moisture Mitigation
If moisture emission is discovered, then proper precautions, such as the use of several topical applications prior to the flooring installation, can be used for moisture mitigation. Some of these topical applications include using reactive penetrants and moisture retarding coatings. Proper preparation of the subfloor is the most labor-intensive aspect of installation project especially with LVT. It is also the most important step that separates the best installation teams from the rest. A high-quality installer will spend close to 70% of their project time on proper floor preparation before even laying their first tile. A few important steps for proper floor preparation include:
Scraping or grinding old adhesive or foreign substance from the concrete. This is especially important when replacing old flooring. A dust-control system could be helpful in high dust-sensitive areas.
Patching and repairing any holes, large cracks, or surface defects in the concrete.
Use concrete patch compound for light repairs.
Use self-leveling underlayment for larger areas.
All concrete subfloors should receive a thorough skim coat with a quality self-drying cement-based finishing underlayment.
3) Determine an appropriate floor covering option.
In some cases, selecting a floor covering that has a higher tolerance for flooring moisture and can perform in concrete slabs with elevated relative humidity levels. Some flooring options, such as a textile composite flooring with pre-applied adhesive backing, perform in areas with elevated moisture. The breathable nature of these flooring products allows moisture to pass through the backing rather than trap it underneath. This method of vapor transmission enables the flooring to be installed with no moisture mitigation. Our floor covering experts can help guide you through available choices for your particular requirement. From moisture testing to installing your new floor covering, we can help! We have water resistant, floating and breathable floors – all great options for a facility with a high moisture rating!
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