It rained heavily on the day that our concrete slab for our house was poured. What problems will result?

Question

This happened last Thursday in Texas. Rainfall totaled .63 in for that day. And it actually rained while pouring the slab. The surface of the slab appeared 'bumpy.' In talking to the contractor, he said it wasn't enough rain to matter. He mentioned something about adjusting the mix to compensate for the extra water. He said that a structural engineer inspected the slab and everything is fine, but I am still a little skeptical.

Answer 1

Actually as long as the rain did not hit the slab you concrete will be all the better. Concrete takes months to cure correctly and if the humidity is really low and the heat is high then your concrete will dry very quickly and crack. The very best time to pour is at night time so that you concrete can cure slowly. If you had the rain actually pour on to the slab that could create problems in the future of surface chipping, because the water makes a thin layer of cement that is very weak. So if the rain did not actually touch the cement or if it was 2 or 3 hours before it rained on the slab no problem.

Answer 2

Depends on what state the concrete was in when it started raining. If the concrete had hardened before the rain started, it did no damage at all. If the surface was still moist (like you could put your initials in it) then the top surface will have been diluted and the concrete will be weakened. In that case, they should remove the slab and start over.