Concrete Cure and Seal: What It Is and When to Use It

What is concrete cure and seal?

Cure and seal is a liquid acrylic, water-based or solvent-based, that you spray or roll on fresh concrete. It does the curing compound’s job of slowing water loss, then stays on as a thin protective film. The Euclid Chemical selection guide describes it as used the same way as a curing compound, but lasting longer and often adding gloss.

A plain curing compound is built to wear or weather off within weeks. Cure and seal carries more resin, so the film sticks around. That extra resin is why the solids percentage on the label matters, covered on our cure and seal solids content page.

What does cure and seal do for concrete?

It does four things, and you should only pay for it if you want most of them:

• Cures: holds mix water in the top of the slab during the first days so the surface gains strength instead of drying out.
• Seals: leaves a film that slows water, salt and dirt from soaking in.
• Changes the look: darkens the concrete and gives it a wet, glossy look, which makes colored and stamped work pop.
• Saves a step: you cure and seal in one trip instead of curing now and sealing a month later.

What it does not do is fix bad concrete. The Euclid guide is plain about that, and it also notes cure and seal can be stained by gasoline, oil and most chemicals. It is a light-duty film, not a coating.

Should you use cure and seal on your pour?

Use it on exterior flatwork where you want the wet look and plan to reseal every few years. Skip it on anything getting flooring, paint or a penetrating sealer, because the film has to come off first. Here is how it shakes out by job.

For stamped and decorative work, the product type matters more. See cure and seal for driveways and stamped concrete for what to look for on those jobs.

The Euclid guide’s alternative for new driveways: use a dissipating cure, clean it off after 4 to 6 weeks, then apply a penetrating water repellent. It says a penetrating sealer on a driveway lasts 5 to 10 years, with no shine.

When do you apply cure and seal to new concrete?

Apply it as soon as the surface water sheen is gone, finishing is done and the concrete won’t mark when you walk on it. The Quikrete 8730 data sheet puts that at 4 to 6 hours after placing, as little as 2 to 3 hours in hot, windy weather, and at least 10 to 12 hours in cool weather.

Don’t wait until the next morning to cure. The Euclid guide says next-day application is not as effective, because the slab has already lost water it needed. If you plan to seal later, cure on time with something else and seal once the slab is dry.

What weather limits do the data sheets set?

Rain, cold and humidity are the three things that ruin a cure and seal job. The numbers vary by product, so read your label, but these are the limits printed on three data sheets and the Euclid guide:

Can you put cure and seal on old concrete?

Yes, as a sealer. The Sakrete Cure ‘n Seal data sheet says to remove dirt, oil, grease, efflorescence and old loose coatings first. Euclid adds that you should let the slab dry 1 to 2 days after pressure washing, because sealer on damp concrete fogs up and turns white.

Water-based or solvent-based cure and seal?

Water-based is the safer pick for most homeowners and any indoor or closed-in space. Solvent-based gives more gloss and darker color and tolerates cooler weather, but it smells, it is flammable, and it bubbles in hot sun. Euclid says that once both are fully dry, they work about the same.

Never run water-based and solvent-based product through the same sprayer. The VOCOMP-25 sheet prints that warning in capitals.

What should the cure and seal data sheet say?

Look for a claim to ASTM C1315, the cure and seal standard, plus the type and class. Type I is clear. Class A is non-yellowing, which you want on colored and decorative work. Some products sold as cure and seal claim only C309, the plain curing compound spec, which has no solids minimum.

The Dayton Superior technical notes give the C1315 numbers: maximum water loss of 0.40 kg/m² in 72 hours at 300 ft²/gal (7.4 m²/L), and minimum 25% solids. C1315 also adds UV, acid and alkali, and tile adhesive bond tests that C309 does not have.

Here is what four data sheets actually claim. This is a sample, not a ranking.

Sources: Quikrete 8730, Sakrete Cure ‘n Seal, VOCOMP-25, Dayton Superior notes.

A C309-only product still cures fine. It just was not tested to the tougher water-loss, yellowing and adhesion limits, and with no solids minimum it may wear off sooner.

How much cure and seal do you need, and how many coats?

Plan on two thin coats, not one heavy one. The Euclid guide uses 300 ft²/gal (7.4 m²/L) as a typical rate, so a 960 ft² (89 m²) driveway takes about 3.2 gallons (12 L) per coat. Put the second coat on 2 to 24 hours later, once the first is tack free.

Spray or roll at right angles to the first pass and don’t leave puddles. Quikrete warns that uneven application shows as uneven color on colored concrete. Euclid calls over-application the most common cause of failure, including bubbling, whitening and peeling.

How long does cure and seal last?

Expect 1 to 3 years. That is the range in Euclid’s CP-05 troubleshooting bulletin, and the selection guide says traffic lanes show wear after a year or two. Reseal every 2 to 3 years, when the sheen is gone and water soaks right into the concrete.

Film thickness is the reason it doesn’t last longer. Euclid’s curing and sealing blog works it out: a 25% solids product leaves about 1.3 mils (33 µm) of dry film at the standard rate, and a 30% product only about 1.6 mils (41 µm).

If your cure and seal turned white, peeled or went blotchy

Most failures trace back to too much product, too many coats, or bad weather during application. A milky or white haze usually means trapped moisture. Solvent-based product can often be re-wet with xylene and fixed in place, while water-based usually has to be stripped. Our guide to cure and seal that turned white walks through the diagnosis and fix.

If the slab is inside and you now want to put tile, vinyl or epoxy over it, the film is the problem, not the look. Start with our curing compound and flooring guide before you put down any adhesive.

What to ask your concrete contractor

Ask these before the pour, so you’re not finding out on the day:

1. Which standard does the product meet: C1315 Type I Class A, or only C309?
2. Water-based or solvent-based, and is the forecast inside the label’s temperature and rain limits?
3. Two thin coats, and at what rate per gallon?
4. Is anything going over this slab later, like flooring, paint or a penetrating sealer?
5. On stairs or a pool deck, is a non-skid additive going in?