Roof leak investigations by drone
Find where water is getting in before you pay for scaffold or opening up. Close-up and thermal drone images of the whole roof, with the likely entry points marked and measured.
Why leaks keep coming back
Water rarely comes in where the stain is. It runs along membranes, decks and joists before it shows inside, so patching the obvious spot often fixes nothing. Repeated coating repairs over a roof that is holding water just move the problem.
How we investigate
- Whole-roof capture: close-up photos of every outlet, seam, upstand and flashing, not just the area above the stain.
- Thermal imaging: shows where water is held in or under the roof covering.
- Marked-up findings: tide marks, ponding and failed repairs marked on the images and measured.
- Confirmation: where the building needs it, our rope access team can water-test the suspect areas from roof level.
You end up with a short, clear scope: where the water is getting in, how big the repair areas are, and whether targeted repairs or a full re-cover makes more sense.
Two real investigations
On a housing estate in Pimlico, the drone found water holding around most outlets and spreading beyond the visible tide marks. At a school in Lee, the defects ran along most of a 61 m roof, not just the patches that had leaked.
How do you find where a roof leak is coming from?
We photograph the whole roof close up, use thermal imaging to see where water is being held, and look at the details that usually fail: outlets, seams, flashings, upstands and old repairs. Where needed we confirm the entry point with a water test.
Why not just send a roofer up?
You can, but on many buildings that first needs scaffold or access equipment, which you pay for before anyone knows what is wrong. A drone survey shows where the problem is first, so access is only paid for where the repair actually is.
Can you look at a leak on a house?
Yes. We investigate leaks on houses and small buildings as well as blocks, schools and commercial roofs.
Is it legal to fly a drone over buildings in London?
Yes, when it is done under the right authorisation. 901 Aerial Surveys flies under a CAA operational authorisation (PDRA01), which covers commercial flights close to people and buildings. Much of London sits inside controlled or restricted airspace, so we arrange any permissions needed before the day.
Do you need access to my property?
Usually only a small, controlled take-off area, such as a car park, garden or a quiet stretch of pavement. Nobody needs to go onto the roof or into the building for the inspection itself.
What happens if the weather is bad?
Drones cannot fly safely in rain or strong wind, so we watch the forecast and move the flight if needed. We confirm the day with you beforehand.
Tell us about the leak
Send the address and what you need to know. We come back with a survey plan, a price and any airspace permissions needed.