Will this find the exact point where water is getting in?

It shows the extent of trapped moisture, not necessarily the entry point, which can be some distance from where the wet patch reads largest, because water tends to travel sideways under a membrane before it pools. A contractor uses the mapped area as the starting point for a closer inspection.

Is this useful for an insurance claim?

It gives dated, photographed evidence of the extent of a moisture problem on the day it was flown, which insurers commonly ask for. It is not a loss adjuster's report and does not price a repair, and the report is written to be clear about that distinction.

Can you survey several blocks or addresses in one visit?

Yes, where they are close together, which is common for managing agents with a small portfolio. Send the addresses and the roof types and a realistic schedule for the evening flights comes back.

Thermal Drone Survey

Damp and Flat Roof Moisture Survey

A thermal check for trapped moisture beneath a flat roof membrane, aimed at landlords, managing agents and homeowners with an extension roof that never quite seems right.

Book a thermal survey Call 07576 544932

Overhead thermal camera image of a flat roof showing an irregular warm zone near a rooflight, suggesting trapped moisture beneath the membrane

Water trapped under a flat roof membrane or within the insulation layer beneath it changes how that area holds and releases heat compared with the dry material around it, and that shows up as a temperature difference at the surface, usually most clearly in the hours after sunset when the roof is cooling.

This matters because a flat roof rarely fails all at once. A membrane can look intact from above for years while moisture spreads underneath it, and by the time a stain appears on a ceiling below, the wet area is usually much larger than the point it is coming through.

A thermal survey does not fix a leak or tell you exactly where water is entering the roof build-up. What it does is show the extent of a wet area that is otherwise invisible, which changes a repair from guesswork and stripping back large sections to a targeted job.

What is included

A full thermal pass over the flat roof area in the right conditions for a moisture read
Extent and rough shape of any suspected trapped moisture mapped against the roof plan
Parapet gutters, upstands, rooflights and roof edges checked, which is where most failures start
A written report within 48 hours, suitable for a managing agent's file or a contractor's quote
A plain note on confidence, and where a physical moisture meter check would confirm the finding
Insurance certificate supplied up front for compliance files

Why the evening flight, specifically

During the day, sun falling on a flat roof warms the whole surface, wet and dry areas alike, which can hide the difference a thermal camera is looking for. As the sun goes and the roof starts to cool, dry insulation loses its stored heat quickly while wet insulation, which holds more thermal mass, cools more slowly and stays measurably warmer for a period after sunset.

That window, roughly the first few hours after a sunny or bright day turns to a clear evening, is usually the most reliable time to fly a flat roof moisture survey. A flat, overcast day with little solar gain to begin with gives the camera much less to work with, which is why the flight is scheduled around actual recent weather rather than a fixed slot in the diary.

What a false positive looks like, and how it gets ruled out

Several things can mimic trapped moisture on a flat roof thermal image: a rooflight or extract vent radiating warmth from inside the building, a shadow cast by a parapet or an adjoining wall, and reflective or metallic surfaces that do not behave like the membrane around them and can throw the reading off entirely.

Each suspected area is checked against its surroundings and against what is physically at that location, a vent, an upstand, a change in membrane colour, before it goes in the report as a likely moisture finding rather than one of these known false readings. Where the picture is actually ambiguous, the report says that plainly rather than reporting a suspicion as a fact.

On the day

How a damp and flat roof moisture runs

Step 1
Roof plan and history
Any known leak history, recent repairs, or a rough roof plan if one exists. None of this is essential, but it saves time on the day if it is available.
Step 2
Timing agreed
Flat roof moisture reads best after a period of solar gain during the day followed by cooling in the evening, so the wet, denser material releases its stored heat more slowly than the dry material around it. That timing is set around recent and forecast weather.
Step 3
The flight
A close, overhead pass across the whole flat roof area, usually in the evening or after dark, working from a lawful launch point nearby.
Step 4
The report
A mapped image of the roof showing any suspected wet areas against the dry field, with a written explanation and a confidence note, within 48 hours.

Behind the work

Kit, cover and qualifications

CAA registered

Operator ID and Flyer ID held, plus the A2 Certificate of Competency. Every flight, including the early morning and after-dark ones this survey often needs, is planned to the rules that apply to the site.

Radiometric thermal camera

A DJI Mavic 2 Enterprise Advanced carrying a 640 by 512 radiometric sensor. Radiometric means every pixel is an actual temperature reading, not just a colour, which is what makes a genuine comparison across a roof or a wall possible.

100 megapixel visual pass

A DJI Mavic 4 Pro with a Hasselblad camera flies alongside the thermal camera on every job, so a warm or cool patch on the thermal image can be matched back to the actual roof feature or wall detail underneath it.

Insured with Coverdrone

Full commercial cover for the operation. Certificates go to managing agents, landlords and insurers as a matter of course, without anyone having to chase for them.

Damp and flat roof moisture