How to Remove Cure and Seal or Concrete Sealer

How do you remove concrete sealer?

Soften it with a chemical stripper and lift it off, dissolve thin acrylic with xylene, or grind it off. Which method fits depends on how thick the film is, what it is, and what goes on the slab next:

This page covers film-forming acrylic cure and seal and sealers. For dissipating, resin or wax curing compounds under new flooring, see how to remove curing compound. Not sure which you have? Curing compound vs cure and seal explains the difference.

What do the data sheets say removes it?

Strippers, strong solvents or abrasion. The makers of the sealers name these removal methods on their own data sheets:

Sources: the EVERCLEAR 350 data sheet, the Super Aqua-Cure VOX data sheet, the WB25 data sheet and the LV25 data sheet. Note that water-based and solvent-based acrylics come off the same ways.

How do you strip cure and seal with a chemical stripper?

Put it on thick, keep it wet, and wait for the film to let go before you touch it. Concrete Network says strippers have to stay wet to stay active, and that multiple applications and hours of dwell may be needed depending on the sealer and its thickness.

1. Protect the surroundings. Cover plants, siding and door bottoms with plastic. Euclid says to keep its stripper off asphalt and painted surfaces.
2. Test a patch. Both stripper data sheets here say to test a small area first. Foundation Armor says its CR100 will not strip all sealers.
3. Go on heavy. McKinnon Materials says 1/16 to 1/8 in (1.6 to 3.2 mm) thick. Foundation Armor says about twice the thickness of the coating, at 50 to 100 ft²/gal (1.2 to 2.5 m²/L).
4. Keep it wet. Work out of direct sun and cover with plastic if it starts to dry. Don’t spray water on it; Foundation Armor says water may deactivate CR100.
5. Wait for the signs. Bubbling, wrinkling or lifting. Brush a spot; if the film comes up easily, it’s ready.
6. Pick up the sludge, then rinse. Scrape, squeegee or wet-vac first. McKinnon says pressure washing softened coating mostly redistributes it.
7. Rinse off all residue. Residue left behind keeps the next sealer from bonding.

Dwell times vary a lot by product. The Euco Clean and Strip data sheet says 20 to 40 minutes is typical, longer for cure and seals, scrubbed on at 100 to 200 ft²/gal (2.5 to 4.9 m²/L). The Armor CR100 data sheet gives 20 minutes to 2 hours for most acrylic sealers. SealGreen’s soy stripper sits about 12 hours.

Does xylene remove acrylic sealer?

Yes, on thin acrylic film, but it’s messy. Acrylic cure and seal re-dissolves in xylene, which is why Euclid lists xylene/xylol or MEK for removing both EVERCLEAR 350 and Super Aqua-Cure VOX. Concrete Decor agrees xylene is effective on acrylic but calls it harsh, flammable and hard on skin.

The catch is that xylene turns the film back to liquid in place. Unless you wipe or squeegee it off right away, it soaks back into the pores and dries again. Concrete Network goes further and says solvents are not strippers: they may loosen a sealer but do little to most decorative sealers long term.

Use xylene for small areas, thin single coats, or a wipe-down after a stripper. For a whole driveway or thick buildup, a stripper or grinder is less work. If you only want to fix a white or uneven film, a light xylene wash may save the coat; see cure and seal turned white.

When should you grind instead?

When the film is thick, layered, unknown, or indoors under new flooring. Foundation Armor lists diamond grinding and sandblasting for both of its acrylic sealers. Grinding removes the film and opens the surface in one step, which is what flooring adhesives and coatings need.

Outdoors on decorative work, grinding has a cost. Concrete Decor says grinding or sandblasting will often compromise the original surface and look of the concrete. On stamped or colored concrete, strip chemically and save grinding for the spots that won’t come clean.

Does pressure washing or acid remove sealer?

Neither works alone on a bonded acrylic film. Concrete Decor says pressure washing without a stripper is generally not very effective, and McKinnon says a pressure washer will not lift a bonded film. Use it to rinse after the stripper has done its job.

Acid does nothing to it. Concrete Network says muriatic, hydrochloric and phosphoric acids have no effect on cured acrylics, polyurethanes or epoxies. McKinnon calls acid etching a prep step, not a removal step, for use on bare concrete after the sealer is gone.

When you do pressure wash, the Euclid cure and seal application guide says to use a fan pattern, not a straight jet, and hold the nozzle 6 to 10 in (15 to 25 cm) from the surface.

How do you know the sealer is gone?

Drop water on it. Sherwin-Williams says a dime-sized bead should soak in within 5 or 10 seconds on bare concrete. McKinnon says the water should spread and darken the concrete evenly. Test in a dozen spots, especially edges, low spots and joints.

Look at a low angle in bright light; McKinnon notes a film-former shows a distinct sheen. Strip again wherever it beads or shines. Then rinse, let it dry, and give it at least 24 hours before resealing, as Concrete Decor advises. If the old sealer peeled rather than wore, read cure and seal peeling, flaking or blotchy before you reseal.

If the slab is getting tile, epoxy or glue-down flooring

Mechanical removal is the safer bet. A stripper can leave residue in the pores, and a slab that passes a quick look can still have film that breaks the adhesive bond. Grind or shot blast, then test with water across the whole floor before the installer starts.

Read curing compound and flooring for the bond tests and what flooring makers ask for. If what’s on the slab is a dissipating, resin or wax curing compound rather than a cure and seal, the removal steps differ, and they’re covered in how to remove curing compound.