I have a slab leak in the kitchen so I saw-cut and chipped about a 15" square through the 4" slab to get to the copper pipe. I centered the square over the area I expected the leak to be, but I was off by about 12+/- inches. The leak is further upstream and appears to be under the doorway between the kitchen and the dining room, but the copper is running THROUGH concrete rather than under the 4" slab. At the doorway, the concrete is thicker than the slab. Is this an interior footing? (It runs under the peak/ridge line of the roof, so is it a footing for a bearing wall?) The copper is about 3 1/2" under the doorway so I would need to chip away the concrete to get to the leak. If it is a footing for a bearing wall, are there any issues with chipping 4" off the top to expose the copper? Any insight and/or advice would be much appreciated.

Thanx

James