Reading a ceiling stain
Brown rings mean the water has been there before and dried, while a dark and growing spot means the leak is active. A moisture meter and thermal camera find the real wet area, which is usually larger than the stain. The source may be a supply pipe, a drain, a roof opening or an appliance in the unit above.
Draining a bulging ceiling
Water pooled behind drywall can bring the whole ceiling down, so a small hole is cut over a bucket to let it out. After that, wet drywall and insulation are removed in sections, leaving as much dry material as possible in place.
Drying the cavity and the room
Air is pushed through the open cavity while dehumidifiers pull moisture from the room. When the leak started in another unit, documentation matters for the building and the insurers, so photos and readings are kept. See roof leak water damage and appliance leak water damage for common sources.



