The most common reason an epoxy floor peels, bubbles, or delaminates has nothing to do with the resin itself. It is moisture moving up through the concrete slab. When water vapor pushes against the underside of a coating with nowhere to escape, it breaks the bond and lifts the finish. That is why reputable installers test moisture before they ever open a kit of epoxy.
There are two industry-standard methods. A calcium chloride test measures the moisture vapor emission rate over a set period, while a relative humidity probe inserted into the slab gives an in-situ reading of internal conditions. Both tell us whether the concrete is dry enough to coat or whether a vapor mitigation primer is required first.
Carolina slabs are especially worth testing. Basements, garages built on grade, and older homes without a proper vapor barrier under the concrete all carry elevated moisture risk. A slab can look bone-dry on the surface and still be wet enough below to ruin a coating.
When readings come back high, we do not cancel the project. We apply a moisture-mitigating epoxy primer engineered to handle vapor pressure, then proceed with the buildout. Testing simply tells us which system to use so your floor lasts instead of failing in a season.
