01
Follow the building connections
Water can move along framing or other surfaces before it drips onto a ceiling. A mark near a chimney may involve roof flashing, masonry, or another moisture source. Give the inspector photographs that show the stain in relation to exterior walls and roof features. Do not assume that replacing the slate directly above the mark will solve the problem.
02
Ask for evidence before authorizing repairs
A useful diagnosis explains the suspected entry point, the route water may follow, and what observations support that explanation. Ask the contractor to distinguish confirmed defects from possibilities that need further investigation. If a controlled test is proposed, it should be planned and performed professionally to avoid adding water damage. Keep before-and-after photographs so recurring symptoms can be compared with the original condition.