High moisture readings after a leak repair, what to do next

Full transcript

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

George

Welcome to the ADI Leak Detection podcast. 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 comes from a homeowner who had a pipe repaired under their kitchen floor, the plumber said the job's done, but their damp meter is still reading high weeks later. They're worried the leak hasn't actually been fixed. What's going on there?

Dave

Yeah, this comes up a lot and it causes real anxiety for homeowners. The repair itself can be perfectly sound, but water that escaped before the fix has already soaked into the screed, the subfloor, maybe the wall base as well. That moisture doesn't disappear the moment you turn the stopcock back on.

George

So the meter's picking up old water, not a new leak?

Dave

Exactly right. The damp meter can't tell you whether water is actively escaping right now or whether it's residual moisture sitting in the structure from before the repair. That's the distinction that matters, and it's the reason you need specialist detection equipment rather than just a moisture reading on its own.

George

So what does ADI actually bring to that situation? What equipment are we talking about?

Dave

The first tool ADI's engineers reach for in this scenario is a thermal imaging camera. Thermal imaging detects temperature differentials across surfaces, so it shows us where moisture has migrated within a wall or floor slab. Active water loss from an unrepaired pipe tends to show a continuing wet front that's spreading or staying wet, whereas residual moisture from a fixed leak gradually dries from the edges inward.

George

That's a really useful distinction. Does thermal imaging work on solid concrete floors, or does it need a surface to read off?

Dave

Thermal imaging works brilliantly on floor surfaces and walls because it reads what's radiating from the surface rather than needing to penetrate it. What it won't do is tell you definitively whether the pipe below is still leaking. For that, ADI's engineers pair the thermal survey with acoustic leak detection equipment.

George

Tell us how acoustic detection works in this context.

Dave

Acoustic leak detection equipment listens for the sound signature of water escaping under pressure. A leaking pipe produces a very specific noise that transmits through the surrounding material, and the listening gear picks that up even through a concrete slab. If the repair is sound and no water is escaping, the acoustic survey returns silence on the supply line. That's your confirmation the defect is genuinely fixed.

George

And if the acoustic survey does pick something up?

Dave

Then you've got an active defect that still needs attention, which is exactly what the homeowner feared. But it also means you haven't wasted time and money on a drying programme for a structure that's still taking in water. Finding that out early saves a lot of disruption.

George

There's another method I've heard ADI mention before, tracer gas testing. Where does that fit in?

Dave

Tracer gas is particularly useful where acoustic equipment can't get a clear signal, which can happen under very thick concrete or where there's a lot of background noise in the building. ADI uses tracer gas by introducing a safe, inert gas mixture into the pipe under low pressure. The gas escapes at any defect point and rises through the floor, and a surface probe detects it. If the pipe is properly repaired, no gas surfaces. It's a very clean pass or fail result.

George

So once you've confirmed the repair is actually sound, what happens to all that residual moisture? Does ADI map that out too?

Dave

ADI's engineers produce a moisture map using calibrated damp meters and pin probes to record readings at multiple points across the affected area. That map tells the homeowner and any drying contractor exactly how far the moisture has spread and how wet the structure actually is. It gives the drying process a proper baseline so you know when the material has genuinely returned to acceptable levels, rather than just guessing.

George

That's really practical. So the summary is: high moisture readings after a repair don't automatically mean the repair has failed, but you do need specialist equipment to tell those two situations apart.

Dave

That's it precisely. Thermal imaging, acoustic equipment and tracer gas testing each address a different part of the question. Used together, they give a definitive answer, and that's a much better position to be in than staring at a damp meter reading and not knowing whether to call the plumber back or just wait.

George

Brilliant. Thanks Dave, that's genuinely useful to know. If you're dealing with persistent damp after a repair and you need that clarity, ADI Leak Detection's engineers are among the most experienced water leak specialists in the UK. We'll be back with another episode shortly.

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.