Interesting basement foundation, need some guidance

[denele]

After a full day of continuous rain I noticed a leak coming from under our stairs. It was coming from a fully boxed in section at the bottom of the stairs, so after pulling it apart I noticed there is a decent amount of foundation that never got poured!

Appreciate any suggestions on what needs to be done to fix this??

 

[Sparky617]

I'd be concerned about what appears to be untreated wood in contact with the concrete floor and walls. You could mix up a bag of concrete to even the floor. If the wood isn't pressure treated, I'd rip it out and replace it with PT wood before you put it back together again.

 

[denele]

I'd be concerned about what appears to be untreated wood in contact with the concrete floor and walls. You could mix up a bag of concrete to even the floor. If the wood isn't pressure treated, I'd rip it out and replace it with PT wood before you put it back together again.

Thanks! Do I need to put some ready-mix concrete to fill in the area where it's missing?

 

[Sparky617]

Structurally, not needed. I think it happened because the stairs were built before the slab was poured. There would be no reason not to finish the floor completely if the slab were poured first. It looks like the concrete oozed under the stair landing and however it set was all that was, or could be done since it wasn't accessible at the time of the pour. It wouldn't cost much to add it, so if you want to do it, go for it. Either way your house won't fall down because of missing couple of cubic feet of concrete.

 

[nealtw]

The problem is with the perimeter drain on the outside, damp proofing on the outside should prevent water from wicking in there.