How to Apply Curing Compound
Spray curing compound once the water sheen has left the surface and finishing is complete, and cover the whole slab evenly at the data sheet rate. These guides cover timing, application, coverage, sprayers and weather.
Guides in this section
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When to apply
The window between the water sheen leaving and the surface drying out.
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How to apply
Sprayer setup, coverage, two coats and what to do if it rains.
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Coverage calculator
Gallons and five-gallon pails for your slab.
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Sprayers
Pump-up vs power sprayers, tips and how to stop clogs.
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Cold weather
Blankets, heat, and why water-based compound must not freeze.
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Hot and windy weather
Evaporation rate, plastic shrinkage cracks and evaporation retarders.
The short version, step by step
- Finish first. Complete all finishing before you spray. Compound does nothing useful if a trowel goes over it.
- Wait for the sheen to go. Spray when the water sheen has left the surface. Too early traps bleed water; too late and the surface has already lost moisture. See when to apply.
- Spray at the data sheet rate. Many products list about 200 ft² per gallon (4.9 m²/L). Use the coverage calculator to turn that into pails.
- Cover it all, evenly. Two light passes at right angles beat one heavy pass. Heavy coats cause peeling and blotching later. See how to apply.
- Re-spray after rain. If rain hits the slab within 3 hours of application, spray it again.
- Keep curing at least 7 days. The membrane does that job as long as it stays intact.
Coverage in pails
| Area | At 200 ft²/gal | At 300 ft²/gal | At 400 ft²/gal |
|---|---|---|---|
| 500 ft² | 2.5 gal | 1.7 gal | 1.25 gal |
| 1,000 ft² | 5 gal (1 pail) | 3.3 gal | 2.5 gal |
| 2,500 ft² | 12.5 gal | 8.3 gal | 6.25 gal |
| 5,000 ft² | 25 gal (5 pails) | 16.7 gal | 12.5 gal |
Double these for two coats. Round up to whole pails, and use the rate on your product's sheet rather than the column that looks cheapest.
Weather changes the plan
Heat, sun and wind dry the surface fast, so the window between the sheen leaving and the surface drying out gets short. Have the sprayer loaded before you finish. See hot, windy weather.
Cold slows everything and rules out water-based products below 40°F (4°C) concrete temperature. See cold weather curing for blankets and other options.