Page 3 - 2018-03-CFR Volume 114 - Old Versus New Concrete Slabs - Staying Out Of Trouble With Both - March 2018

Don’t think that you can use a sheet moisture miti-
gating membrane on a new or old slab without risk
either. We just got involved with a massive carpet
tile installation failure that included the use of a sheet
topical membrane that was actually lifting off the sub-
strate from vapor build up beneath it. The architect
and end user thought this would be cheaper, faster
and easier than doing complete mitigation that the
flooring contractor suggested. Now it’s going to cost
way more to fix as everything has to come up, miti-
gation done and the business housed in the space
totally disrupted. Not so cheap now is it?

Water that came Through Membrane
Old slabs have their own set of issues. They can be
very porous, unstable and broken. The strength and
thickness of the concrete slab can be compromised
from years of use and traffic; there can be badly
worn areas; the condition of joints can be poor and
the concrete can have all kinds of cracks. There is
the chance, even if not visible of contamination on
the surface by grease, oil, or other spillage affected
by use, effects of extreme temperatures changes,
chemical effects that can compromise the concrete
and the new flooring material that might not be ap-
parent and also abrasion of the slab. If the slab is on
or below grade they may not have a vapor retarder
at all, or one that is too thin and compromised or one
that is placed beneath the granular layer or one that
does not meet the standard.

Compromised Concrete Floor Concrete Floor Core Sample March
Core Sample and No Vapor With Vapor Retarder
Retarder
Commercial Flooring Report
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