Can a drone inspection find the cause of a roof leak?

Internal evidence gives you the destination: where water appears, where it has run, which timbers are wet. Drone imagery gives you the candidate entry points above and around that area — a cracked slate, an open flashing, a blocked valley, a failed bedding joint.

Where those two lines of evidence meet, you have a diagnosis rather than a guess. Where they do not meet, the honest conclusion is that further investigation is required.

Water travels. It enters at one point, runs along underlay, a batten or a rafter, and emerges somewhere else entirely. A covering that looks perfect can sit above a failed underlay lap. A flashing that looks sound may not be built far enough into the brickwork to see.

In those cases the next steps are roof space inspection, targeted physical access, or a controlled water test.

That drone imagery detects leaks beneath a covering, or that a survey proves what condition concealed materials are in. It does not, and saying otherwise leads to repairs aimed at the wrong place.

Thermal imagery can sometimes indicate anomalies consistent with moisture, but it is an indication requiring confirmation, not a finding on its own.

Record the symptom and the weather it comes with. Have the roof space looked at. Have the roof surveyed. Where those three agree, repair the identified defect. Where they do not, invest in the further investigation rather than in speculative work.

Some leaks only appear in particular conditions: driving rain from one direction, heavy snow load, or after prolonged saturation rather than a brief shower. A dry-day survey may show no active evidence at all, which is a limitation of timing rather than a clean bill of health.

Where a leak is intermittent, noting the exact conditions that trigger it and passing that to whoever surveys the roof narrows the search considerably, and a second visit in the relevant weather sometimes settles a question a single dry visit cannot.