Curing Compound for Contractors: Specs, VOC Limits and Bulk
On a spec job, three things pick the curing compound: the ASTM type and class in the spec, the VOC limit where you pour, and what the next trade puts on the slab. Get all three right before you order, and use a dissipating cure where flooring or coatings follow.
Guides in this section
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ASTM C309
Types 1, 1-D and 2, Class A and B, and the water-loss test.
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ASTM C1315
The cure and seal standard, and how it differs from C309.
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VOC limits
Look up the VOC limit for your state, air district or country.
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State DOT requirements
How DOTs specify and approve curing compounds.
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Specifier checklist
What to put in Section 03 39 00 and what to ask for in submittals.
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Test for curing compound
Water drop test, bond test and what the results mean.
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Best curing compounds
Data sheet comparison of the compounds contractors buy most.
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Hot and windy weather
Evaporation rate, plastic shrinkage cracks and evaporation retarders.
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Cold weather
Blankets, heat, and why water-based compound must not freeze.
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Cost
Price per gallon and per square foot, checked at retailers.
Read the spec first
- ASTM C309: the curing compound standard. Type 1 is clear or fugitive dye, Type 2 is white pigmented; Class A has no limit on the solids, Class B must be resin.
- ASTM C1315: cure and seal films, with a tighter water loss limit (0.40 kg/m²) and classes that rate yellowing.
- DOT work: many state DOTs accept only products on their approved list, and some add stricter limits than C309.
- Submittals: our specifier checklist lists what to ask for, from the data sheet to the flooring compatibility letter.
Check the VOC limit before you order
The federal limit for curing compounds is 350 g/L, with 700 g/L allowed for C1315 cure and seals. California, Canada and several eastern states hold everything to 350 g/L with no 700 category, and Southern California's South Coast district caps most uses at 100 g/L. Look up your area in our VOC limits table.
Protect the flooring handoff
Most bond failures start with a cure and seal left on a slab that later gets adhesive or a coating. Where flooring follows, spec a dissipating resin cure, get the flooring maker's sign-off, and run the water drop and bond tests before the installer arrives. See testing for curing compound.
Products by job
| Job | What to use | Examples on our review pages |
|---|---|---|
| Interior slab getting flooring or a densifier | Dissipating resin, C309 Type 1 | Euclid Kurez DR VOX, W.R. Meadows 1100, Dayton J11W |
| Bare slab, inside or out | 25% solids cure and seal, C1315 Class A | Dayton J22WB, Concrete Sealers USA TS202 |
| Exterior paving in sun | White pigmented, C309 Type 2 | W.R. Meadows 1600-WHITE |
| Stamped or colored exterior | Solvent acrylic cure and seal | Nox-Crete Cure & Seal 1315, Concrete Sealers USA TS200 where 700 g/L is allowed |
For the full side by side, see best curing compounds.
Weather and bulk buying
- In heat and wind, spray right behind the finishers. See hot weather curing.
- In cold, water-based products can freeze in the drum and on the slab. See cold weather curing.
- Drums and totes cut the price per gallon. See curing compound cost and shelf life and storage before you stock up.