Acid Stain

Fixing Acid Stain Problems on Concrete Floors

Jan 1, 2026 Justin Richardson

Acid stain is reactive, which means it is not fully under your control — uneven color, weak patches and areas that simply refuse to take are normal outcomes, not signs you did it wrong. The fix is almost always the same: seal what you have, then correct the color on top with dye, which is not reactive and does not care what the slab is made of.

A concrete floor with acid staining issues.

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Six steps to correct it

1 · Clean: Scrub and rinse every residue off with ProClean Degreaser™, then let it dry
2 · Seal first: One coat of acrylic sealer before the dye. Counter-intuitive, but it is what stops porous and outdoor concrete drinking the dye unevenly
3 · Mix the dye: Follow the packaging. Goggles and gloves
4 · Apply: Shake the sprayer constantly. Spray right-to-left, then north-to-south. Thin coats — it dries almost instantly. Three to four coats is usually enough; add more for a deeper color. Mop up any pooling
5 · Wipe back: Once fully dry, remove excess colorant with a dry buffer, soft cloth or dust mop
6 · Seal again: The same acrylic sealer you used in step 2, by pump sprayer

cleaning concrete floor with acid staining issues — Cleaning an old stain job.

Sealing the concrete surface before applying the dye — Malayan Buff showing staining problems while wet.

Ventilation is not optional

Solvent-based sealers indoors need a mask and real airflow. In a poorly ventilated space — a basement especially — use a water-based sealer instead. This is the single most common way people make an unpleasant job genuinely unsafe.

What the correction looks like

This restaurant floor is the same technique at commercial scale — the areas that would not react were brought into line with dye rather than fought with more acid stain.