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How to Fix Old Concrete
Fixing old concrete may mean just re-doing
a previous coating or floor system that needs maintenance,
or starting over from scratch and reapplying a coating or
it may include structural repairs of cracks, spalls and
other defects in the concrete itself.
 The
first step in "fixing" older concrete is to first
do an accurate and thorough survey of what conditions currently
exist.
A starting point is to measure all the square
footage involved (see Measure
for help on that). Measuring right away serves two purposes:
- You know the exact square feet which later allows you
to develop cost estimates for materials and labor, and
- Takes you over the whole area so you can inspect it
in detail.
A detailed inspection and noting of problems
can often give clues as to the cause of the problems you
see. Knowing the causes then allows you to avoid them during
this "fixing" process.
Sometimes coating or floor covering failures
have underlying causes. Sometimes the problem is with the
material or product, or the application techniques.
While poor or inadequate products often play
a role, the preliminary issues of concrete preparation are
probably the most common cause of failures.
Generally speaking, it is good to devote the
majority of your time and effort to proper preparation.
Your final job is only as good as the surface you put it
on. So think...preparation, preparation, preparation.
So, 1st measure.
2nd, a thorough evaluation of existing coating
and condition of concrete.
If a coating is peeling or scraping off, it
is always better to get rid of it so you have a good substrate
for the next step of putting a new product on the floor.
You can use chemical and water means. Applying
a cleaner or stripper and washing with water, such as out
of a pressure washer. Pretty messy and risks emolsifying
old coating and soaking it further down into concrete. Not
always a good idea.
Or mechanical means. Grinding with abrasive
pads, or grinding machines. Or shot blasting.
Here are a some links with info about renting
and using concrete prep equipment to give you an idea of
what is possible. Using the right equipment is the key to
making a seemingly impossible task--like removing failed
coatings from concrete--very realistic for DIYers.
Prepare
concrete surfaces for repair
Remove
floor coatings with surface grinders
Info
on grinding / shot blasting / concrete floor prep
More info will be posted. In the meantime,
feel free to call or write for assistance with your project
or answers to questions.
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A floor grinder removing an old epoxy coating
from a concrete floor.
This can be a virtually dustless process
if done correctly by attaching a vacuum to the grinding
machine. Notice hose leaving grinder. It attaches to a
vacuum positioned out of the way of the work area.
NOTES ON
Acid etching, acid washing
Using a 10% Muriatic Acid wash on concrete
is something most people have heard about and assume should
always be done.
Not exactly.
Muriatic acid is hydrochloric acid. It often
is used to open up the surface of concrete and reduce the
alkalinity for coating application.
It reacts on bare concrete but does nothing
to remove coatings, or contaminants from concrete.
So if you need to strip or remove a previous
coating... do not bother using any acid... they will not
remove coatings.
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