How Is a Concrete Floor Prepared Before Coating

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Every slab gets ground before anything is rolled on. The prep described in the notes at epoxy concrete floor coatings riverside writer philadelphia (written around epoxy floor work in Riverside, CA) comes down to a clean, open surface and a dry slab, in that order of inspection.

Profile comes from grinding

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Coatings bond mechanically, so the concrete needs an open texture. The industry describes that texture with ICRI concrete surface profile numbers, and thin systems commonly target a light ground profile. Diamond grinding removes laitance, the weak film on top of the slab, and opens pores more consistently than acid etching. Etching alone is not a substitute on a slab with sealer or a troweled-hard surface. Grinding also leaves a profile that a primer can wet into, which matters for any epoxy base coat.

Oil, sealers and old paint

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Oil and grease soak into concrete and block adhesion. Garage slabs in Riverside County often show dark patches under parked vehicles, and those areas need degreasing and sometimes deeper grinding to get below the stain. Existing sealer, paint or curing compound has to come off completely. A new coating only grips as well as the layer under it, so a polyaspartic topcoat over a peeling sealer will peel with it.

Moisture is tested, not guessed

Vapor rising through a slab can push a coating off the floor. Common tests are the calcium chloride method, ASTM F1869, and in situ relative humidity probes, ASTM F2170. Slabs near the Santa Ana River can hold more moisture than a hillside lot, so the reading matters more than the neighborhood. A plastic sheet taped down overnight is a rough screen at best. It does not replace a formal test, and a damp patch under the sheet only says the slab needs the real measurement.

Cracks and spalls

Cracks and spalls are filled with a compatible repair material before coating. Chase the crack, fill it, and grind the repair flush. Moving cracks can still telegraph through the finished surface, because a coating does not stop a slab from shifting. Inland Empire soils and temperature swings from the Santa Ana winds season keep some joints active, so saw cuts and control joints are left as joints and not filled solid.

Dust and the first coat

Dust left after grinding weakens adhesion. The floor is vacuumed with a HEPA equipped unit before priming, then checked by hand for powder. Only then does the primer go on, followed by the base coat. Broadcast systems with vinyl flake or quartz sand depend on that first layer being tight to the slab, since the broadcast media adds weight and the clear coat adds wear on top. New concrete also needs time to cure and dry before any of this starts, and it cannot be coated the week it is poured.