Retrofit basement footers
I’m adding a lally column to and undersized midpsan girder in the basement and I’m about cut my holes through the slab. My footers are going to be 24”x24” but after marking it out I thought it might be less intrusive to cut the slab hole smaller and instead dig out more underneath the existing slab to get my 24 inches. Any benefit to do this or not do this? Am I over thinking it and just making it more difficult to remove soil for no reason.
Your basement slab may have some layers between it and the undisturbed soil. You would have some issues trying to sort it all out with an undersized hole.
I would cut the slab as large as you need the footing.