Sometimes when core drilling
you run against a fairly tough concrete wall. This wall had 1 1/2" steel reinforcing rebar every 13-inches embedded into the concrete. Right in the location that the plumbers need a six-inch core drill hole through the wall was 2 of the rebars had somehow gotten entangled inside the wall. Added to the pressure of the job was there were black sharpie marks made on the black water barrier where GPR (ground penetrating radar) operators had scanned the wall for any rebar that would be in the way of the core drill bit because the developer wanted to avoid cutting any rebar if possible.
Well, we cut through the two pieces that were matted together making the total amount of metal cut roughly 3-inches by 3-inches of the radius of the diameter of the 6-inch core drill hole. But in the end, we find six-inch coring in reinforced concrete commercial walls with alot of metal well within our abilities, cutting the concrete is the easy part.