The most common epoxy failure we get called out to fix has nothing to do with the epoxy itself. It's peeling, bubbling or flaking that traces straight back to poor surface preparation. Bare concrete is porous and often coated in old sealers, oil, dust or laitance, the weak top layer left after a slab is poured. Roll epoxy straight over that and it bonds to the contamination, not the concrete. Proper prep means mechanically opening the surface with diamond grinding so the epoxy keys into sound concrete, repairing cracks and low spots, and checking for moisture that would push a coating off from underneath. It's slower and messier than a quick acid wash, and it's the step budget installers skip to win a job on price. Done right, prep is what turns a coating into a floor that still looks sharp after years of cars, foot traffic and cleaning.