We are subbing out construction of our pool and the first guy hired was to do demolition of a knee wall and footer that's in the way. When he got into it he confirmed what we suspected... that the knee wall was built on top of an old pool that was tipped in on itself and backfilled. So... the new pool will end up built inside the old pool. The demo guy said that the best way to do this would be to excavate out a rough opening and pull out all the concrete... then he would backfill the hole so the pool layout guy could mark the excavation and let our pool excavator cut the precise hole.
We talked to our excavator and he said that was for sure the cheapest way to go - if he hit any concrete in the excavation his charges go up. The demolition guy quoted us a fixed price to bust up and pull out any remnants of the old pool and backfill.
Anything I should be concerned about here?