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Why Coatings Fail

Why Garage Floor Coatings Fail

There are many horror stories of do-it-yourself epoxy floor coating jobs gone terribly wrong.  The stories range from the coating never curing, strange chemical reactions between types of coatings, out-gassing with bubbling occurring, and blushing.  The most common complaint is the floor coating lifting from the applied concrete surface.  These issues do not only affect the “do-it-yourselfer” but can plague professional installers as well.  When selecting a contractor to install your floor coating, be sure to consider their experience, length of time they have been in business, and warranty policy in case any problems occur.

In this article we examine the common causes of epoxy coating failure and offer some tips to prevent this from happening to you.  The key to proper application of any floor coating is the amount of effort taken to prepare the surface.  There are several reasons why epoxy floor coatings generally fail and the first is related to moisture penetrating from below the surface.  Concrete is a very porous material and will basically wick water to the surface where it evaporates. Since most floor coatings including epoxy are non-breathable, wicking moisture forms a hydraulic pressure beneath the coating causing delaminating.  This occurs if your garage floor does not have an adequate vapor barrier in place or if it was damaged during construction.  A moisture issue usually does not present itself overnight, but rather over time.  Small or large bubbles may form as water beneath the surface builds. If you see bubbles in your floor coating, use a razor knife and cut a small slice in the bubble.  Squeeze the surrounding area to see if water escapes to determine if you have a moisture related problem. For this reason always test your floor for moisture before coating!  This is a simple process explained in this garage floor moisture testing article.

Do not apply non-breathable coatings if moisture drive is present in your garage floor.

Garage Floor Coating FailureThe second cause of coating failure also deals with floor preparation.  Inadequate cleaning, specifically not removing grease and oil can cause a failure.  The concrete must be completely clean by adequately cleaning and degreasing the surface.  Almost all cars will drip some form of fluid or track in grease and oil from the roadway at some time. It is imperative to remove these contaminates from the porous concrete prior to coating the garage floor.  I recommend you review the Garage Floor Cleaning tips found on your sister site Garage Epoxy for more information. The concrete surface of the floor must be properly profiled to create a solid surface for the epoxy to bond to. Concrete surfaces contain many impurities, minerals, powder, and dust.  This exposed surface must be blasted, ground, or etched to remove the top surface so the epoxy will have a clean solid surface to form its bond.  An easy method of profiling involves renting a commercial sander with diamond grinding pads attached.  They usually rent for under $40 a day with an addition charge for the stones ($75 at my store).  For a little over $100 you can easily profile a 2 car garage in few hours.  An alternate method involves using caustic muriatic or phosphoric acid to chemically etch the floor.  There are certain safety precautions you must take when using these acids so be sure to visit our Garage Epoxy website for more information on this type of preparation.

Sometimes you may find that a concrete sealer has been applied to the concrete.  Sealers penetrate the surface of the concrete rendering them water resistant and also resistant to chemical bonding of floor coatings.  You can test if the floor has a sealer by spraying some water on the floor and then observing if the water beads up.  Use this method also on your oil and grease stains to see if you have cleaned them up well enough.  If you discover a sealer had been applied, it is best to rent a concrete floor grinder to remove the surface of the concrete where the sealer resides.  When renting a floor grinder is out of your budget, a strong etching with muriatic acid may do the job.  Following the etching process, be sure to perform the water test again.  If the water still beads, you will need to re-etch the garage floor using a stronger dilution of acid or profiling the surface with a bead blaster or floor grinder.

Epoxy coatings usually consist of two parts (part A and part B).  These two components must be mixed in the exact ratio recommended by the epoxy manufacturer.  Failure to mix the components exactly, or failure to mix them thoroughly, can result in the epoxy never properly curing.  It could hardened to a sticky substance or remain a gooey liquid you may be able to scrape up.  Either way it creates one big ugly mess!

Almost all floor coatings have a usable shelf life. Be sure to verify the material you are applying has not expired.  You will find the fresher material spreads and flows more easily, and this is especially true with urethane or polyurea based coating materials.  As clear urethanes age in the can, they begin to turn amber in color and thicken making them more difficult to apply and more likely to leave roller or brush marks in the final finish.  Look for vendors that have a high turnover of inventory and have the freshest product in stock.

Color streaking, bubbles, or blush are issues that may occur when applying garage floor coatings.  If using a heavy nap roller, air may be introduced during application that will rise to the surface creating bubbles as the product cures.  Concrete contaminants could also form these air pockets, so be sure to blow out the garage good before coating. Moisture caused by extreme temperature variations during application and curing, excessive humidity in the air, contaminants, or incomplete mixing may be the culprit of color streaks or blush.  Blush is a white or greasy waxy film caused by a reaction of the epoxy hardener with moisture in the air.  These issues can also be the result of not waiting enough time between coats, or applying the product too thick.

Bubbles and blush must be removed by sanding before additional coats may be applied.  Finally, a good idea is to perform a test application on a small area prior to coating the entire garage floor. Mix a small amount of your epoxy coating and apply to a one foot section of the prepared floor surface as per manufacturer recommendation.  After the material has cured, test that the coating is adhered to the floor adequately by performing a pull test.  Apply a strong duct tape (such as Gorrilla tape) to the coating and then peel it off, repeating in several different directions . If the coating sticks without lifting from the floor surface, you have a good mechanical bond.  You should perform this test over a questionable area of the garage floor to be sure you have it cleaned sufficiently and properly profiled the concrete surface.

So, to sum this up, remember that preparation is the golden key to success in your garage floor coating adventure.  Without taking the necessary time to perform proper preparation, your hard work and financial expense may only create a giant, hairy mess.  It is super difficult to deal with any of the issues presented in this article.  Trust me, I have experience a few of these mistakes first hand when starting out, and the remedy to rectify the situation often involves removal of the entire surface and starting over fresh with proper preparation.

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Why Garage Floor Coatings Fail
Article Name
Why Garage Floor Coatings Fail
There are many reason that a garage floor coating could fail even though you believe the floor surface was properly prepared. Here's the authoritive guide on the many causes and how to prevent your garage floor coating job from turning into a nightmare!