Concrete moisture vapor emission is a natural occurrence of any concrete slab. Concrete is a porous substance that absorbs and wicks moisture from either above or below the slab. Most garage floors are poured with a vinyl vapor barrier underneath, however they can be damaged during pouring and tamping of the concrete, or even non-existent. If concentrated moisture is present it will create a hydraulic pressure under your top coating making it lift, bubble and peal.
Prior to coating a garage floor, it is highly recommended you test the garage floor for moisture before applying a top coat.
Freshly poured slabs have a high water content that must evaporate during the curing process. New concrete should be allowed a minimum 30-60 days to cure before a coating is applied. This pertains to all floors whether the slab is above or below grade. Besides the curing process of new concrete, long established floors can also wick moisture from sources below the slab, even when approved moisture barriers were installed. This moisture will naturally wick to the surface and can easily break the bond of floor coatings causing your garage floor coating system to fail.
Humidity and temperature both have a direct effect on the pressure exerted on the concrete surface measured in “pounds per square inch”. Inside your garage the static vapor pressure is often one half the pressure seen inside or below the concrete garage floor slab. This indifference causes the moisture to literally be sucked upward, often trapped just beneath the floor coating materials. The hydraulic pressure exerted can easily lift epoxy and other floor coatings causing them to bubble and peel. It is crucial to use even the most basic testing methods to determine if your floor has an unacceptable moisture issue prior to coating. Read More →
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. Read More →