How long before a concrete slab can be rained on?

between 4-8 hours

Once the concrete has been finished (between 4-8 hours after pouring) and has set hard enough for walking on, the effects of rain should be minimal.

Can you lay a concrete slab in the rain?





Of course, pouring concrete mix in the rain is best avoided altogether, but sometimes it isn’t possible to wait. If rain is forecast on the day you are pouring concrete, make sure the site is well covered with plastic sheets and tarpaulin to keep the ground as dry as possible.

Can you pour a slab on wet ground?

Damp ground will not be a problem unless is can not support the weight of the concrete. Cement/concrete does not “dry” , it cures , a chemical reaction. It absorbs water to cure, as noted , some concrete applications are sprayed with water to aid the cure.