Page 5 - 2017-12-CFR Volume 111 - How Many Types of Moisture Tests - December 2017
P. 5
The cost of materials for the CaCl test can add up quickly. Here’s More on Concrete—Lew Migliore
Once you understand that you should al-
ways test the concrete, old or new, before
installing any flooring material you have to
understand also the variables. No two
concrete slabs are the same. Each project
you encounter will confront you with some
sort of challenge – large or small – that
could compromise the installation or integ-
rity of the flooring material. So thinking a
slab is dry just because it looks that way to
you and because the old flooring may not
have failed doesn’t mean the new one
won’t. Never gamble with a concrete slab -
and make sure you record and photograph
everything so that any issue in the future
will be thoroughly documented.
Getting moisture readings with the RH test is fast, easy, and reliable.
Concrete slabs never dry. There is always
some moisture in them there concrete
slabs. The environmental conditions in the
space will allow for the moisture in the slab
to move in and out of it, that’s physics at
work. This is particularly so in a building
that the HVAC system is cycling at night
and on the weekends. Not so much a
problem in a healthcare facility which has
stable HVAC operation but in an office type
building this is certainly going to be the
case and even in a school. We see this
issue all the time. Another thing to be
aware of is that older buildings and that
could be something as “new” as one built
in the early 2000’s, may not have a vapor
retarder beneath the slab. Certainly a
building built in the 60’s, 70’s and 80’s
won’t have that protection. Consider also
that slabs poured in non-vented pans
above grade and always suspect light
weight or pumped concrete which is highly
hydrated. Again, you can’t know by look-
ing at concrete and conclude that it’s dry
so you have to test and certainly in this
case you can assume there is moisture.
Moisture in a slab is like blood in your
body. It’s always there and something is
always going on with it even though you
5 Commercial Flooring Report December 2017
