Recently we had a leak in our basement, and upon opening the wall found that the pipe had cracked. After figuring out that it was a waste pipe for the kitchen above, we called a plumber who came and replaced that section of pipe as well as one right above it where another crack had formed.
This image is of the lower crack. You can see at the top of the picture, the next segment of the pipe curves back into the concrete, where it is followed by another curve that sends the pipe up the wall. The second crack is on the pipe heading up immediately after the second curve.
This has been repaired, but upon questioning the plumber, he has no clue what caused it. Unfortunately, the insurance company would like a list of possible causes, and I have nothing to tell them. Does anyone have any ideas?