Page 3 - 2018-11-CFR Volume 122 A Smart Guide to PVC Backed Modular Carpet and Vinyl Flooring November 2018
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backed material is installed over a concrete slab that
      is emitting high levels of water vapor. There are also
      instances where this breakdown has happened due
      to issues within the PVC backing itself even when
      the PVC backed flooring material is installed over a
      perfectly acceptable floor. It is extremely important
      for the contractor to fully understand and rigorously
      document that the sub floor meets or exceeds ALL of
      the requirements of the manufacturer.  In a typical
      situation where PVC backed flooring is installed over
      an out of specification sub floor, the emitted vapor
      may condense to liquid water under the PVC backed
      carpet– usually with a pH of about 12 or 12.5 which
      is about the internal pH of concrete itself. Inevitably,
      this high pH condition comes in contact with the plas-
      ticizer that is continually diffusing out of the cured
      PVC plastisol that serves as the backing. What hap-
      pens is that the high alkalinity acts as a catalyst for
      the hydrolysis reaction and the plasticizer breaks
      down into its component parts.




















           PLASTICIZER HYDROLYSIS FROM A WET SLAB – FLOATING
               INSTALLATION - NOT A MANUFACTURING ISSUE

      This in itself would not be a problem except for the
      fact that the alcohols liberated by this breakdown
      have an EXTREMELY pungent odor most often
      smelling like a new plastic shower curtain or Play
      Doh. This odor can be so objectionable that it has
      caused buildings to be evacuated for months while
      the contaminated slab is either cleaned or removed
      and replaced. Remediation of this type of issue can
      result in contentious lawsuits and the dollars are
      HUGE.
      DO YOU HEAR THE CASH REGISTER YET?
      GUESS WHO GETS BLAMED FOR THIS? YOU
      GOT IT – THE INSTALLATION CONTRACTOR.
      This is why it is doubly important to dot the “I’s” and
      cross the “T’s” when it comes to vapor emission
      rates, In situ RH values and the surface pH of the
      concrete when you are working with PVC backed
      material.  And, as we mentioned previously, this con-
      dition can also be inherent in the material itself.


      3                                            Commercial Flooring Report                            November 2018
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