Page 3 - 2018-11-CFR Volume 122 A Smart Guide to PVC Backed Modular Carpet and Vinyl Flooring November 2018
P. 3
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