My garage pad is 24x28, thickened edge monolith slab. No issues and I know my thickened edge is over designed. Rebar at either 12 “ OC or 16”-I can’t remember .
As I mentioned before sounds like combination of poor concrete and improper subgrade prep and now possible too small size of footing to bear the load. Maybe your footings are founded on uncontrolled fill soils and not native / undisturbed soils or weak subgrade.
Lots advice provided by others. Get all parties involved and get another opinion from a second contractor and possibly a geotechnical engineer
|