I just applied some Quikrete brand Quick-Setting Cement (No. 1240) to fill a 16x16x1.5" hole in my basement floor.

Regarding curing, the datasheet just says

"Efficient damp curing is required for 48 hours"

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I googled "Efficient damp curing" and all the results were the same datasheet, so this doesn't seem to be a standard industry term. Can anyone clarify what it means?

For now, I've just covered it with a plastic sheet held up off the fresh concrete by a 2x4 straddling a couple of bricks on either side of the new concrete. Weighed the sheet down around the perimeter so air can't flow through. Turned off the basement dehumidifier and central AC for the night so it doesn't get too dry. It's about 22'C (72F) and about 50% humidity in the basement.

Is that sufficient or should I spray or mist it with more water in the morning and remainder of the 48 hours period?


  • 1
    I always read/heard to keep it damp. Misting every so often should keep it damp instead of drying out. About the only way to make it efficient is to use an automatic mister.
    – crip659
    Sep 7, 2022 at 0:30
  • 2
    Once the initial set has occurred (it's no longer wet, surface is hard, but still weak) lay a wet rag under your plastic. on the surface. Easier than building a dam around it and flooding it, though that's a good technique too.
    – Ecnerwal
    Sep 7, 2022 at 3:18

1 Answer 1


As the package says, concrete does not dry, it cures. This is a chemical process that requires water.

Normal evaporation can remove the water from the outer layers of the concrete, and the chemical process is exothermic (meaning it produces heat), so evaporation is always a risk factor. Therefore, keeping it damp will ensure there is the right amount for it to harden. If the surface gets too dry you may end up with a rough surface that spalls easily. Stick to the prescribed proportions though (don't add extra water), as too much water in the mixture may result in more porous or less smooth concrete.

Regular misting will help (especially in a climate with low humidity). Another alternative is covering with thick plastic (so that the ideal composition that you produced while mixing the concrete will be preserved).

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