Can the chronic moisture problems be avoided and long- term flooring success be achieved?


Did you know…

  • Because of today’s fast track construction schedules, the average life-cycle of floor coverings has been reduced from 20 years to 7-8 years.
  • Most of these moisture failures occur within the first year of installation.
  • To remediate these failures, it will cost building owners approximately 2-6 times more to replace a floor system than the original cost of the floor.

Why does this happen?

  • Concrete is cured after 28 days, but NOT DRY…
  • Your everyday average concrete slab constructed over an impermeable moisture barrier will take (under ideal conditions) approximately 92 days to get to a suitable moisture level for a resilient or wood flooring installation.
  • Rule of thumb is approximately one month per 1 inch of concrete thickness (under ideal conditions)…
  • It takes approximately 12 gallons of water to hydrate 1 sq/yd of the average concrete mix design. On average an additional 22 gallons of water is used for convenience to maintain its workability during placement.
  • This is approximately a 65% surplus of water that needs to evaporate!

It isn’t just new construction that’s susceptible to subfloor moisture vapor related damages.

  • Poor grading, slope to building, or water run-off around the perimeter of an existing building will find its way under the concrete slab and, through capillary action, “wick” its way through the concrete slab and begin to deteriorate water-based adhesives, patching & leveling compounds. Even if the structure has an under-slab vapor barrier, it is becoming more and more frequent that said barriers have been installed improperly or were damaged/torn during installation.

Keep in mind…

  • Moisture moves from lower temperature and high humidity to higher temperature and lower humidity
  • Moisture vapor can read differently at different times of year
  • Moisture vapor may vary throughout the slab’s surface
    Below is a typical building envelope, in which the top of the structure (roof) is waterproofed through the typical construction process. The problem is that most architects & engineers neglect to waterproof the underside of the structure. Moisture vapor in the sub-grade, below the slab, will almost always have a relative humidity (RH) level of 100%. The ambient RH of an acclimated building in our region is somewhere between 20% – 40%. Thus, the interior of the building will always be drawing moisture vapor through the porous concrete slab in an effort to reach equalization – this is a never ending cycle.


The good news is, chronic moisture problems can be easily prevented.

  • Mapei Planiseal VS Fast is an alkali-resistant, two-component 100%-solid epoxy coating that effectively stops moisture related problems with floor covering. In all cases, moisture vapor emission rates (MVERs) of 100% RH or up to 25 lbs. per 1,000 sq. ft. (11,3 kg per 92,9 m2) per 24 hours were reduced to below the limit of 3 lbs. per 1,000 sq. ft. (1,36 kg per 92,9 m2) required for many types of finished flooring, when the designated film thickness was applied.
  • Used in a single-coat application system, Planiseal VS Fast offers low viscosity with high-density resins that effectively reduce MVER by penetrating deep into the substrate and effecting consolidation well beneath the surface.
  • Once installed, Planiseal VS is compatible with a wide number of primers and adhesives typically used with flooring installations, such as tile, vinyl composition tile (VCT), carpet, sheet vinyl, wood and other floor-finishing products.


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