We found these problems with this chimney during a recent home inspection.
The base flashing had been removed and someone painted on roofing cement in an ill attempt to stop water leaks. From the ground these repairs looked a little off, but nothing very alarming. My home inspector antennae went up just enough to make sure I got a closer look. These repairs have been leaking for sometime and there is an unknown amount of wood rot surrounding the chimney in the attic.
The chimney cap mortar has completely disintegrated and was falling off the chimney while we were there. Rain had been getting inside and causing even more problems. Upon closer examination, we found a crack at the outside of the chimney which carried through to the clay liner inside. This is certainly a fire and safety hazard!
The buyers are certainly glad we climbed the roof and found these dangerous and very costly problems during our home inspection.