If there's one thing that determines whether an epoxy floor will last for decades or fail within months, it's the preparation. Not the quality of the epoxy, not the skill of the application — the preparation. Here's what professional epoxy floor preparation involves and why it matters.
Epoxy doesn't stick to smooth concrete — it bonds to a properly prepared surface. Think of it like painting a glossy surface versus sanding it first. Without the right surface profile, the epoxy sits on top of the concrete rather than bonding into it. Eventually, the coating will peel, delaminate, or wear through prematurely. Proper preparation creates a mechanical bond that keeps the epoxy locked to the concrete for decades.
Diamond grinding is the gold standard for epoxy floor preparation. An industrial diamond grinding machine uses rotating discs embedded with diamond segments to abrade the concrete surface. This does two things: it removes any existing coatings, laitance (the weak surface layer of concrete), and contaminants, and it creates a surface profile — a slightly rough texture similar to medium-grit sandpaper — that the epoxy primer can grip into.
Diamond grinding is not something you can do with a handheld sander. Professional grinders weigh hundreds of kilograms and are connected to industrial vacuum systems to capture dust. The difference between a diamond-ground surface and an unprepared or poorly prepared surface is visible and measurable.
Our installation process always starts with diamond grinding — it's the foundation of every Rhino Coating floor.
Once the surface is ground, any cracks, spalling (where the concrete surface has broken away), or other defects become clearly visible. These must be repaired before coating. Cracks are chased out with a grinder to create a clean channel, then filled with a high-strength epoxy repair mortar. Expansion joints are treated with flexible sealants to allow movement. Loose or hollow areas of concrete are identified (often by tapping with a hammer) and addressed.
Skipping crack repair leads to the epoxy coating cracking along the same lines — the coating is only as strong as the substrate beneath it.
Concrete contains moisture — it's porous and can wick water from the ground beneath. Before applying epoxy, we test the moisture content using a calibrated moisture meter and may also perform a calcium chloride test or relative humidity probe test for larger floors.
If moisture levels are too high, several solutions exist: applying a moisture-tolerant primer, installing a moisture vapour barrier, or in severe cases, addressing the source of moisture before proceeding. Ignoring this step means risking osmotic blistering — where moisture pressure pushes the coating off the concrete.
Once the floor is ground, repaired, and confirmed dry, a primer coat is applied. The primer penetrates the surface profile, seals any remaining dust, and provides the ideal surface for the epoxy build coat to bond to. We use moisture-tolerant epoxy primers that can handle residual moisture levels that would cause problems for regular epoxy.
The primer is applied by squeegee and roller to ensure even coverage and worked into the surface profile. This step is often skipped in DIY applications — and it's one of the most important layers in the system.
Acid etching (using muriatic or phosphoric acid) is sometimes suggested as a DIY alternative to diamond grinding. While it does etch the surface, it's inconsistent, introduces moisture, requires careful neutralisation and rinsing, and doesn't create the same bond profile as mechanical grinding. It's also hazardous to handle. Professional installers do not rely on acid etching for epoxy flooring — diamond grinding is the standard for a reason.
Every floor we install goes through this complete preparation process — no shortcuts, no skipped steps. It's why our floors last 15–25+ years and why we confidently offer a 10-year residential warranty. If you're considering epoxy flooring and want it done properly, request a free quote or call us on 07822 032335.
