The water appearing on a ceiling is almost never directly below the hole. Water travels along joists, down insulation and across membranes before it shows, which is why the traditional approach of opening up where the stain is so often finds nothing.
The problem with opening up
A leak is a guessing game if you can’t see the path. Lift a flat roof covering in the wrong place and you’ve created a second problem, paid for a repair that wasn’t needed, and still don’t know where the water is getting in.
The same applies to floors with buried heating pipes, to basements and to tanked structures. Breaking out concrete to look for a leak is destructive, expensive and frequently in the wrong place.
What electronic leak detection does
Electronic leak detection locates breaches in a waterproof membrane or a pipe run without taking the building apart.
The principle, broadly, is that an intact waterproof layer is an electrical insulator. A breach in it isn’t. By wetting the surface and introducing a low voltage, a defect in the membrane can be located because current passes through it where it passes through nothing else.
The result is a point on a plan rather than a general area, which means the repair opens up only where the fault actually is.
Where it’s used
- Flat roofs and terraces, including inverted roofs with ballast or paving over the membrane, where the covering is otherwise inaccessible
- Green roofs, where lifting the build-up to search is enormously disruptive
- Balconies and podium decks
- Tanked basements and below-ground structures
- Wet rooms and tiled floors
- Buried pipework and underfloor heating circuits, using related tracing methods
When it’s the right answer
It’s the right answer when the location is genuinely unknown and opening up would be destructive. On a ballasted flat roof over an occupied room, or a tiled terrace above a kitchen, the cost of a wrong guess is high enough that locating the fault first is obviously worthwhile.
It’s not the right answer for everything. A roof at the end of its life with multiple failures doesn’t need a leak located, it needs recovering. Part of our work is saying so.
It sits inside a wider investigation
Finding the entry point is one part of it. Understanding why the building is wet is the other, and the two aren’t always the same question.
Water showing inside can be a membrane breach, a failed detail at an upstand or outlet, condensation, a plumbing defect, or rising or penetrating damp with nothing to do with the roof at all. Treating the first thing you find as the cause is how a building ends up with three repairs and the same stain.
Our approach is to establish the cause rather than the symptom. See our guides to defect investigation and damp and timber surveys.
What you get
A report identifying where the defect is, what it is, and what needs doing about it, with the location recorded against a plan of the roof or floor so a contractor can go straight to it.
Where the findings matter to a claim or a dispute, the record also stands as evidence of what was found and when.
Talk to us
We carry out defect and fault finding surveys using electronic leak detection across the Cotswolds, Gloucestershire and Bath. See our problem solving page or get in touch.
Frequently asked questions
Yes. It locates the defect without opening up, so any work that follows is confined to the actual fault rather than exploratory.
Yes, and that’s one of the cases where it’s most worthwhile, because searching by hand means lifting the whole build-up.
Related tracing methods are used for buried pipework and heating circuits. Establishing which of the possible sources is responsible is part of the investigation.
