Re: Garage Floor Paint

["Brant M. Miller" <brant@xxxxxxxxxxxxxx>]

" Asmaradezn@domain.elided" said, in part: As an Architect, I can tell you that=

you must coordinate your selection with
the conditions underneath the slab.    Otherwise vapor pressure can
delaminate your coating."

More important than vapor pressure can be osmotic pressure.  We installed=

an epoxy floor in a laboratory building a few years back.  The building a=
nd
slab were engineered items with code-meeting drainage.  The installation
process called for pre-cleaning the concrete floor with HCl.  The
subcontractor used a partially spent HCl that contained other disolved
material and then did not thoroughly wash the floor.  There were dried
salts of ionic compounds on the floor when the epoxy was installed.

After the first winter, the floor began to bubble.  Analysis of bubbled
areas showed that a concentrated ionic solution (salt water, but it wasn'=
t
NaCl) was contained in the bubble and that the bubble formed not by the
flooring separating from the concrete but by the concrete failing just
below its surface in tension!  The concrete slab was acting as an osmotic=

membrane.  The concentrated ionic solution was trying to dilute itself by=

drawing water across the slab.  The buildup of pressure caused the bubble=
s.

Moral of the story:  If you install an epoxy floor, ensure that the
concrete surface is real clean prior to the installation.

Brant

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