Even polished concrete isn’t completely immune to staining or etching. If spills are left too long, if harsh chemicals are used, or if the floor’s protective layer wears down, you can end up with discolouration, dull patches, or rough, etched spots. But not all damage needs a full re-polish. In this guide, we’ll explain how to fix stains and etching in polished concrete — and when it's better to clean, polish, or reseal.
A stain changes colour but leaves the surface smooth. An etch dissolves surface minerals and creates roughness or dullness. Run your hand across the spot — if it feels rough, it’s etched. This distinction matters because removal techniques are different for each type of damage.
Before trying to repair anything, clean the area with a pH-neutral floor cleaner and a soft microfiber cloth or pad. This removes dirt, residues, and reveals the true extent of the mark. Never start aggressive repair work until the area is clean — dirt can make staining appear worse than it is.
For stains, try applying a poultice made from pH-neutral cleaner mixed with a fine powder (like talc or baking soda). Apply it over the stain, cover with plastic wrap, and let it sit overnight. This draws the stain out of the pores. Wipe clean and reapply if necessary — most stains lift in 1–2 applications.
If the stain is very shallow, buff the area using a white pad and a spray of clean water. This can lift minor organic stains or remove light surface haze. Use a low-speed buffer or hand polisher. Don’t grind aggressively — you risk cutting through dye or guard layers if you go too deep.
For mild etching, re-polish the affected area using 200 or 400 grit resin pads. Feather outward to blend into the surrounding finish. Keep the machine or hand polisher moving steadily and avoid gouging deeper into the floor. This restores surface clarity without needing a full re-grind.
If etching has weakened the surface in one spot, applying a lithium silicate densifier after polishing can re-harden the area. Mist it lightly, allow to penetrate, then burnish after curing. Densifiers help close up pores and reduce future marking.
Once the stain or etch is removed, reseal the repaired section using the same product that was originally used — penetrating sealer for natural look, or guard for added gloss. Mist and spread thinly, blending into the surrounding sealed floor. Burnish if required.
Always feather repairs outward. Burnish lightly across a wide area to avoid a visible "patched" look. The repaired section should match the reflectivity, colour tone, and texture of the surrounding floor once finished.
Stains and etching usually happen because of improper maintenance or spills not being cleaned quickly. After repairs, review cleaning protocols: use only pH-neutral products, clean spills immediately, and avoid dragging furniture or equipment without protection across the floor.
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