Damage without an active drip
The kitchen ceiling was marked and damaged, but initially read dry on the moisture meter. Camera checks through spotlight openings revealed no active leak.
Narrowing down the source
Bathroom dye testing did not bring dye through the ceiling. Hot and cold supply pressure tests showed no drop.
Agreed ceiling openings allowed closer inspection. ADI found a wet overflow waste pipe connected to the hot water cylinder. Small pieces of wood between the pipe and its rubber gasket were preventing the joint from sealing.
Replacing the faulty connection
The engineer replaced the affected section and fittings with new plastic waste pipework. Testing after the repair found no further leaks.
In this case, the initial dry reading did not identify the fault. Direct inspection of the concealed connection was needed to establish the source.