Every peeling epoxy floor we’ve ever been called out to fix has the same root cause. It’s not the paint, and it’s rarely bad luck. It’s what happened — or didn’t happen — to the concrete before a single coat went down.
Most big-box epoxy kits tell you to prep with an acid wash. It sounds thorough. It isn’t. Here’s what’s actually happening beneath your tires, and why we grind every slab to bare concrete instead.
What Acid Etching Actually Does
Acid etching uses a diluted muriatic acid solution to lightly roughen the top of the concrete. It’s cheap, it’s fast, and it’s the method almost every DIY kit recommends because it doesn’t require equipment. The problem is depth — acid etching barely touches the surface, leaving behind a thin, inconsistent profile that’s still full of laitance, sealers, and contamination from years of tire traffic and cleaning products.
Epoxy bonds mechanically, not chemically. It needs a rough, open pore structure to grip into. Acid etching gives it a shallow scratch. Diamond grinding gives it a foundation.