Should I be concerned about torrential rain after concrete walls poured?
legovkram
| Posted in General Discussion on
Currently building a house. Hole dug, footings poured and allowed to cure for 2-3 days. Just when the concrete was poured into the forms for the walls, a storm started and dumped over four inches of rain in our area over the next two days with more to come. The poured wall contractor was going to remove the forms the day after the pour, but they were rained out and the forms will have to stay on over the weekend (walls poured on Thursday). The water in the hole is now approximately two feet deep, covering the footings and up about 16″ on the forms. Should I be concerned about the integrity of the concrete and the foundation system as a whole?
Replies
If the concrete had been placed in the forms and consolidated (vibrated to eliminate voids) before the rain started, I would not worry.
remember that concrete does not really dry, the chemical composition absorbs water as it sets and cures.
If the rain was heavy and steady right as they were finishing up, some of the top surface may show exposed aggregate. but if it had enough time to set, you may not even find any trace.
Thanks for your reply. We've now had close to 7" of rain since it was poured. The water is now about 2-3 feet deep in the hole, and yes you can see exposed aggregate on the exposed concrete at the top of the forms. Not sure if that's a problem?
Once the concrete is set in place, the wetter the better for curing. https://www.concretenetwork.com/curing-concrete/
whatever effect the rainfall had on the top surface of the wall, it should be localized, and not hurt the rest of the wall. If the exposed aggregate is firmly bonded into the concrete, it should stay that way.
The criticality of this surface depends on how the rest of your house will interface with the foundation.
If you want a secondary opinion in addition to whatever the concrete contractor and builder says, you can engage the services of a local engineer to evaluate the result.
As long as flowing water cannot take the fines out of the concrete mixture you should be fine. The real worry is concrete drying too fast, this will weaken the structure.
My concern would be the liquidification (sp?) of the soils under the footings. A basic rule is if your footings are into the water table the width should be doubled. Might want to shoot some elevations to check for differential settlement.
My guess is that you are ok. Ask a structural engineer to come review the site, might cost $500 but give peace of mind. Once it stops raining you can dig a sump and start de-watering your hole. Aside from the top surface of the foundation wall being washed out a little the concrete within the forms should be just fine.
Good luck! We have record breaking heat here...