Guides for HomeownersContractors
ConcreteCuringCompound

Concrete Curing Compound: The Buyer-Side Guide

Know your bucket before you pour.

There are three kinds of curing compound. Each one is perfect for some slabs and a headache on others. We'll tell you which is which, and why.

Find my pail How much do I need?
DISSIPATING RESIN ASTM C309 · TYPE 1 WHITE PIGMENTED ASTM C309 · TYPE 2 CURE & SEAL ASTM C1315

ASTM C309 · Type 1 or 1-D

Dissipating resin

Holds water in for the cure, then breaks down in sun and traffic, often within 4 to 8 weeks.

Flooring later?
Usually the right pick. Bond test first.
Watch out for
Indoors with no sun, it may never dissipate.
Read the guide

ASTM C1315 or C309

Cure and seal

Cures and leaves a protective film that lasts about 1 to 3 years. The go-to for driveways and decorative work.

Flooring later?
Risky. Test your exact adhesive first.
Watch out for
Turns white if rain or dew hits it too soon.
Read the guide

ASTM C309 · Type 2

White pigmented

Reflects at least 60% of daylight to keep big pours cooler. Standard on DOT paving and bridge decks.

Flooring later?
No. It has to come off first.
Watch out for
Wax versions never dissipate on their own.
Read the guide

Which one are you?

Homeowners and contractors buy for different reasons. Each page starts with the answer for your job.

I am a homeowner Curing my own driveway, patio or garage floor
  • Which jug to buy
  • How many gallons
  • Fixing white haze and peeling
Open the homeowners guide I am a contractor Meeting the spec on a job I have to sign off
  • C309 and C1315 types
  • VOC limits and DOT lists
  • The flooring handoff
Open the contractors guide

Something already went sideways?

The six problems behind most curing compound searches. Each guide gives you the fix in the first two lines.

The flooring won't stick The compound film blocks adhesive. Bond test at 72 hours; shot blast it off if the patch lets go. My cure and seal turned white Moisture got trapped. Solvent films often re-melt with xylene; water-based ones usually get stripped. Is there compound on my slab? Drip some water on it. If it beads up instead of soaking in within seconds, a film is still there. When exactly do I spray it? The moment the water sheen is gone after final finishing. Too early traps bleed water; too late does little. Peeling, flaking or blotchy Usually sprayed too heavy or in too many coats. The right coverage rate fixes it, not more product. Is it even legal where I work? Most of the US caps curing compound at 350 g/L VOC. Southern California's limit is 100 g/L for most uses.

Pick the right pail. Then buy the right number of them.

Which one do I need?

Will flooring, tile, epoxy or polish go on this slab later?
Is the concrete colored, stamped or decorative?
Is the slab indoors or outdoors?

Answer the questions to see a recommendation.

How much do I need?

Units

0 gallons

200 ft²/gal (5.0 m²/L) is the rate used to test compounds under ASTM C309, not a product rate. Use the coverage rate on your product's data sheet.

Open the full product chooserCoverage calculator with metric units and tips

From the last trowel pass to a floor that stays down.

Not to scale. When to apply curing compound

MINUTESHOURSDAYSWEEKS Final finish Trowel or broom Sheen gone: spray Within minutes, not hours 3 hours Rain before this? Re-spray 7 days Minimum curing period Water drop test Beads mean film's still there 72-hour bond test Holds? Install the floor 4 to 8 weeks Dissipating film breaks down in sun

How to read the label on the pail.

Five lines on the side of the bucket tell you almost everything. Here's what each one means.

  1. The standard. C309 means it cures. C1315 means it also seals and passed extra UV, alkali and bond tests.
  2. Type and class. Type 1 is clear, 1-D has a dye that fades within 7 days, Type 2 is white. Class B means resin only; Class A allows wax.
  3. VOC. 350 g/L is the US federal limit. Southern California allows 100 g/L for most uses.
  4. Coverage. Spray at this rate. Going heavier is the top cause of peeling and blotching.
  5. Storage. Water-based products are ruined by freezing. Keep them above 40°F (4°C).

ASTM C309 in plain English VOC limits by state

EXAMPLE
CURE & SEAL 25 5 GAL
Water-based acrylic curing and sealing compound
  • Meets ASTM C309 and ASTM C1315
  • Type 1, Class A and B
  • VOC less than 350 g/L
  • Coverage: [rate from data sheet] ft²/gal
  • DO NOT FREEZE

Start with these.

Curing basics How long does concrete take to cure? Product guides Curing compound vs sealer vs cure and seal: what's the difference Flooring How to remove curing compound Standards ASTM C309 explained

Quick answers.

The questions we hear most from contractors and homeowners.

Is a curing compound the same as a sealer?

No. A curing compound (ASTM C309) holds mix water in for the first days. A cure and seal (ASTM C1315) also leaves a protective film that lasts about 1 to 3 years.

Can I tile or glue flooring over it?

Not without testing. ACI 302.1R advises against curing compounds on slabs getting resilient flooring unless the maker issues a compatibility letter. Run a 72-hour bond test; if it fails, remove the compound, usually by shot blasting.

How long until a dissipating cure breaks down?

Usually 4 to 8 weeks with sunlight and traffic. Under a roof, or when sprayed too heavy, it can take far longer. Confirm with a water drop test.

What if it rains right after I spray?

Spray it again. A Corps of Engineers spec quoted by the FHWA calls for a new coat on any area hit by rain within 3 hours of application.

Can I keep leftover product for next season?

Only if it never froze. Store water-based compounds above 40°F (4°C); state DOTs reject carryover lots that have frozen. Stir gently before use.