How and Why To Epoxy Paint Your Concrete Slab --
Understanding Concrete Painting With Epoxies
Your Host and Tour Guide:
Paul Oman, MS, MBA - Progressive Epoxy Polymers,
Inc.
Member: NACE (National Assoc. of
Corrosion Engineers), SSPC (Soc. of Protective Coatings)
"Professionals helping Professionals"
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- HOW TO REACH US
copyright 3/3/97
Concrete slab floors are found in nearly all industrial and commercial sites. Should
you paint or coat them, or leave them alone?
If you are completely new to Epoxy Floors and are exploring the idea of having an
epoxy floor, click here
to get the basic requirements before you call to discuss and/or order.
Shot blast surface preparation - Associated Surface Prep (California) - Peter Hughes - 530-662-3696
REASONS TO COAT YOUR FLOOR
Concrete floors are coated for several reasons. These include:
1) to improve chemical resistance,
2) to prevent the concrete from sweating (epoxies are used for this application,
3) to impart a non-skid surface,
4) to seal the surface from moisture and/or reduce dust, and
5) for appearance sake.
POSSIBLE PROBLEMS
In some cases getting a suitable, long term bond between the concrete and the coating
can become career or profit destroying task. Because of these potentially dreadful results, consider coating your
slab only if you really need to and only if you are willing to perform suitable surface preparation (which will
help greatly in avoiding possible problems). It is often difficult to say exactly why a coating on a cement slab
will fail (not stick, peel, blister, etc). Reasons can include:
1) a layer of dust or dirt or the surface,
2) too smooth, oily or waxy a surface (from previous coatings or contaminants),
3) a damp surface,
4) surface salts or ions that are already present or forming/collecting (can be from
surface waters, contaminants or from the concrete itself),
5) vapor pressure and or water flow within the porous concrete itself before, during,
or after the coating has been applied, or
6) a weak surface layer of concrete (from either very old or very new concrete). Other
problem situations include existing 'active' cracks and/or expansion joints. If you simply paint over them the
coating will crack or peal when movement or shifting takes place.
SURFACE PREPARATION
Surface preparation is often a judgment call based upon the location, condition and history
of the existing concrete. Perhaps the surface needing the least preparation is the typical cement sidewalk outside
your house that has been 'weathered' for several years and has never been oil stained, painted, etc. The existing
factory or work floor is the floor that should cause you the most concern. Waxes, sealers, spills, dissolved salts,
are all possible problems awaiting discovery.
Your best chance at a successful floor coating job in this case is to shot blast the
floor, removing the top layer and providing a new, fresh surface profile. I would then waterblast the surface and
include a salt-removing agent. Finally wet vac the surface dry, sucking away the water, dust, and dissolved salts.
MODERN SOLVENT-FREE COATINGS
Our company sells a line of solvent-free epoxies for floor coating. Solvent free epoxies
have no strong fumes to deal with and their wet thickness equals their dry thickness. In other words, if you apply
20 mils of coating or fill in a tiny void with the wet epoxy, it will harden at 20 mils instead of shrinking and
re-exposing any filled in cracks or voids. An 50% solvent (50% VOC) epoxy would require applying 40 mils of product
to get 20 mils of dry epoxy. Of course, you probably cannot apply 40 mils in one coat so two or coats would be
necessary (add in time and labor costs). Actually, it is even difficult to apply 10-20 mils of a solvent based
coating without getting 'alligator' textures of peaks and indents with wet paint trapped underneath due to trapped
solvent under the top layer of dry paint. No solvents also means nothing to soften or weaken existing coatings
or finishes (such as the adhesive under floor tiles that are being encased or sealed in epoxy). These epoxies can
also be applied to wet or damp (or even submerged) floors. Remember that moisture is one possible cause for floor
coatings to fail.
COST OF EPOXIES
As the above paragraph suggests, a $50/gallon, 50% solvent epoxy has the same amount
of coverage as a $100/gallon, 0% solvent (0% VOC) product without the dangers and fumes of the solvent, nor the
potential extra labor costs of solvent based product.
Epoxies generally sell for between $20 and $1,000 per gallon. To a degree, you get what
you pay for. A premium grade epoxy could easily contain raw materials costing the manufacturer between $25 and
$50-$60 per gallon. Like all products (but less than most) there is a several hundred percent market-up to pay
for salaries, one or more layers of distributors and/or reps, marketing, packaging, R&D, overhead, profit,
insurance, advertising, etc. To make very inexpensive epoxy means either using a lot of inexpensive solvents and/or
inert, inexpensive fillers. This affects performance and quality.
EVALUATING EPOXIES
On a cost basis, evaluate your epoxy options on a cost per square foot, per dry mil basis.
That removes the solvent factor (but not the fumes safety problem). Look for ease of application and reapplication.
Beware of a problem know as 'amine blush' which leaves behind a waxy residue on the epoxy surface. Look for an
ASTM E648 fire testing of the epoxy (or resin) system. Some epoxies require extreme care in getting the mix ratio
100% correct. Instead, look for a more 'field friendly' mix where being 'close' is good enough.
Third-party web site link on concrete floor surface preparation:
Concrete Patching and Repair Page - click
here
Does your floor have a vapor barrier? UNDESTANDING VAPOR TRANSMISSION ISSUES WHEN COATING CONCRETE article - CLICK HERE
Knowledge is Power - We like informed consumers!
Learn the basics of epoxy at our educational EPOXY 101 page -
Click Here.
Finally, email us back with your questions or comments before
you buy - EMAIL HERE
Progressive Epoxy Polymers, Inc. carries three lines of floor epoxies. Our Industrial
Floor epoxy is an excellent quality, solvent free epoxy. It is available in beige, and light gray. Our waterbased
Waterbond (med. gray only) is a user friendly epoxy. Rough Coat is a tan epoxy with grit already mixed in. Visit
our products catalog at: www.epoxyproducts.com/b_floor.html
Related epoxy flooring articles: click here
ABOUT PROGRESSIVE EPOXY POLYMERS, INC.:
Progressive Epoxy Polymers provides multi-vendor epoxy and speciality coating products to clients and customers
all around the world. Customers include government agencies, diving companies, utility and petroleum companies,
diving companies, flooring contractors, epoxy injection companies, waste water facilities, nuclear, and mining
operations. Many of our epoxies can be applied underwater as necessary. "If we don't carry an epoxy product
for your specific needs, it's probably not available!"
Progressive Epoxy Polymers also carries epoxies and related products for pleasure boat owners and maintains
a separate web site for the recreational marine market. Progressive sells the least expensive boatbuilding epoxy
in North America ($33 per gallon in 15 gal units).
For more background information about us - CLICK HERE
Visit our products catalog at: www.epoxyproducts.com/products4u.html
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