I plan on water-curing a concrete slab (4' x 8' x 4"). I figured I would just spray it with some water to keep it wet. How often do I need to spray water on the slab? When should I start spraying it?

1 Answer 1


Cover fresh concrete with some foil to prevent the water from evaporating. After one day you can start to spray. The duration depends on the quality of the concrete. It could be from one to seven days.

The most important part is to keep the concrete wet so there is enough water for the hardening process.

  • 1
    The quality of the cured concrete depends on the duration, too - the longer you keep it wet, the stronger it gets, though there are diminishing returns.
    – Ecnerwal
    Commented May 5, 2017 at 0:18
  • @Ecnerwal. That is correct. Lack of water is fatal
    – Decapod
    Commented May 5, 2017 at 10:13
  • I don't see freshly redone concrete sidewalks or even roads being sprayed or kept wet during curing. Does this mean that these surfaces are not as durable as they could be and would be if kept wet? Or would spraying result in a surface which would be hard but slicker than desirable? Commented May 5, 2017 at 10:38
  • 1
    foil to cover concrete? I use plastic sheeting when it is hot. a light spray every couple of hours really helps the concrete cure well and reduces cracking especially when the temps are up.
    – Ed Beal
    Commented May 5, 2017 at 13:11
  • @EdBeal. With the plastic sheeting you do the same. The only purpose is to prevent water from evaporating. Keeping the water in the concrete is important see also comment of Ecnerwal.
    – Decapod
    Commented May 5, 2017 at 15:57

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