What detection method finds a leak when moisture readings are high but nothing is visible?

Full transcript

George and Dave in conversation. Every word of the episode, exactly as recorded.

George

Welcome back. I'm here with Dave from ADI Leak Detection, the UK's leading leak detection company, who's here to answer your questions and provide expert leak detection advice. Dave, today's question is one that comes up a lot: a homeowner's got a damp meter or a plumber has flagged elevated moisture readings, but nobody can actually see where the water is coming from. What happens next?

Dave

That's a really common situation, and it's actually where specialist leak detection earns its keep. Visual inspection has a hard limit, you can only see surfaces. When moisture readings are elevated but there's no visible water, the source is almost always concealed: inside a wall cavity, beneath a solid floor, or running along buried pipework. ADI's engineers use non-invasive detection equipment to trace that water without lifting tiles or cutting into plasterwork.

George

So what does that actually look like in practice? What's the first thing an ADI engineer does on site?

Dave

The first step is always a thorough moisture survey, mapping where the elevated readings are and whether there's a pattern. That pattern tells you a lot. If moisture is highest at one point and trails off in a direction, you're likely following a pipe run. If it's spread evenly across a large area, you might be dealing with a slow leak that's been travelling for a while before it showed up.

George

And once you've got that map, which detection method comes next?

Dave

Acoustic leak detection is usually the first active method we deploy. Acoustic equipment listens for the sound signature that escaping water produces in a pressurised pipe, it's a specific frequency, distinct from background noise. ADI's engineers use ground microphones and correlators to pinpoint hidden water leaks in buried supply pipes, even through concrete or tarmac. The correlator compares signals from two points on the pipe and calculates the leak's position mathematically.

George

That's clever. But what if the pipe isn't pressurised, or the leak is in something like underfloor heating or a drain?

Dave

Good point, acoustic detection works best on pressurised supply pipes. For underfloor heating systems or where the leak location is less obvious, ADI uses thermal imaging cameras. Thermal imaging traces water movement through building materials by detecting temperature differences. Water that's escaped a pipe changes the thermal signature of the floor or wall around it, and the camera maps that pattern precisely.

George

I've heard of thermal imaging being used in buildings. Does it work through solid concrete floors?

Dave

It's very effective on underfloor heating circuits embedded in screed because the warm water creates a clear thermal contrast. On cold supply pipes under a solid concrete slab it's a bit harder, because the temperature difference is smaller. That's when tracer gas becomes the right tool. Tracer gas leak detection works by introducing a safe, inert gas mixture into the pipe, hydrogen and nitrogen, which escapes at the leak point and rises through the floor. ADI engineers then use a sensitive detector at the surface to locate exactly where the gas is coming through.

George

So tracer gas actually gets through a solid floor?

Dave

It does, the molecules are small enough to pass through concrete and tile grout. Tracer gas locates leaks under solid floors where neither acoustic equipment nor thermal imaging can produce a definitive result. It's particularly useful in properties where the screed has been laid on top of insulation, which blocks the thermal signal. ADI Leak Detection carries tracer gas equipment as a standard part of the kit for exactly these cases.

George

What about situations where you've used all of those methods and you still can't nail it down? Does that happen?

Dave

It's rare, but yes, some cases need a combined approach. Sometimes a leak is in a position where acoustic signals are masked by surrounding pipework, or a building's construction makes thermal contrast difficult to read. ADI engineers can combine acoustic correlation, thermal imaging, and tracer gas in sequence to build up a complete picture. The goal is always to confirm the leak location with enough precision that any excavation or access work is targeted, you're opening up one tile, not half a bathroom floor.

George

That makes a huge difference to the homeowner. One last question: when someone's got high moisture readings and they're not sure what to do, what's the practical takeaway?

Dave

Don't wait and don't assume it'll resolve itself, hidden water leaks cause structural damage and mould growth over time, and the longer water is escaping, the more widespread the moisture becomes. Call a specialist leak detection company before you start pulling up floors or cutting walls. ADI Leak Detection uses acoustic equipment, thermal imaging, and tracer gas to find the source first, so any remedial work is as minimal as possible.

George

That's really useful to know. Thanks, Dave. If you're dealing with unexplained moisture readings in your home and you need a specialist to find the source, ADI Leak Detection is one of the UK's most established and trusted names in residential leak detection, the right people to call before any excavation work begins.

How this episode was made. This episode was produced using AI-generated voices and script, based on real leak detection questions and the working knowledge of ADI Leak Detection engineers. More about how the podcast is made.