Underfloor Heating Leak Detection in London
An underfloor heating pipe failure gives you very little to work with at first. Your boiler pressure drops, the system tops up more often than it should, or a patch of floor feels warmer than the rest. By the time damp appears at the surface or your screed begins to crack, the leak has often been running for weeks. Because the pipework is buried, there is no visible drip and no obvious starting point.
Signs of an Underfloor Heating Leak
An underfloor heating pipe failure gives you very little to work with at first. Your boiler pressure drops, the system tops up more often than it should, or a patch of floor feels warmer than the rest. By the time damp appears at the surface or your screed begins to crack, the leak has often been running for weeks. Because the pipework is buried, there is no visible drip and no obvious starting point.
ClearFlow uses thermal imaging and tracer gas to find the exact fault location before anything is lifted. Thermal imaging reveals the temperature anomaly caused by escaping heated water, narrowing the search to a specific zone. We then introduce a hydrogen-nitrogen tracer gas into the isolated circuit and detect it at the surface using an electronic probe, accurate to within a few centimetres through concrete, screed, or tile.
We work with homeowners, managing agents, and contractors across London. Our written report includes the confirmed fault location, photographs, the method used, and a clear repair recommendation. All major UK insurers and loss adjusters accept it without question. Where access is needed, we mark the exact point on the floor so your contractor opens only the minimum area required.
- Boiler pressure dropping repeatedly without an obvious cause
- Cold spots or uneven heat distribution across the floor
- Unexplained rise in water or energy bills
- Damp patches appearing on the floor surface or screed
- Floor tiles lifting, cracking, or separating at the grout lines
- Musty smell coming from the floor or skirting area
- System constantly needing to be topped up with water
- Visible moisture seeping through grout lines or tile edges
How We Locate Underfloor Heating Leaks
We review the symptoms, building type and pipe layout before selecting any equipment.
One or more methods are deployed to identify the source zone, typically narrowed to within 10–30 cm.
A second method cross-checks the result before we mark the repair point — no guesswork.
A written report with findings and photographs is issued — suitable for insurance claims.
Underfloor Heating Situations We Cover
Wet system under screed
The most common underfloor heating configuration in London properties. If the pressurised circuit is losing water, we isolate each loop individually to identify which section is failing, then use tracer gas to pinpoint the breach within centimetres. Only the affected loop requires attention, keeping disruption to a minimum.
Pipe fault under concrete slab
Pipes embedded in a solid concrete slab are the hardest to access and the most expensive to open unnecessarily. Tracer gas permeates through the slab and registers at the surface, giving a precise fix point before any concrete is broken. This applies equally to ground-floor slabs and structural concrete in flats.
Leaking circuit under tiled floor
Lifting tiles without knowing the fault location can disturb the entire floor and damage an otherwise intact heating circuit. We map the heat signature with thermal imaging first, then confirm the exact point with tracer gas. Only the tiles directly above the fault need to be removed for the repair.
Fault in a new installation
Installation faults often present within the first heating season as joints or compression fittings settle under thermal cycling. We identify the failure point quickly, giving your installer the precise location they need to make a warranty repair. The process is fully documented so there is no dispute about where the fault occurred.
Insurance trace and access claim
Most buildings insurance policies include a trace and access clause covering the cost of locating a hidden pipe fault. We provide a written report with photographs and methodology accepted by all major UK insurers and loss adjusters. We can liaise directly with your insurer on request.
Underfloor heating in a bathroom
Bathrooms see repeated thermal cycling and moisture exposure, which can accelerate failure at pipe joints and fittings over time. We investigate without lifting tiles, confirm the fault location precisely, and document the findings so the repair can be carried out with minimum disruption to the room.
What You Can Expect
We've been detecting hidden leaks across London for years. Every engineer is directly employed by us, DBS-checked and WaterSafe registered. We don't subcontract.
- Pinpoints the exact fault location before any floor surface is lifted
- Thermal imaging and tracer gas used together for confirmed results
- No Find No Fee: you pay nothing if we cannot locate the source
- Written report accepted by all major UK insurers included as standard
- Non-invasive process: the floor is marked, not opened, until the repair stage
- Same-day appointments available across London, seven days a week
Trusted Across London
Absolutely quality service and what plumbers should exemplify. Turned up when they said, was kind, answered all my questions and wasn't being dodgy with anything. Skilful and efficient! Would highly recommend.
The technician arrived on time, was polite, and explained the process clearly before starting. They used advanced, non-invasive equipment to locate the leak quickly without causing any unnecessary damage to my property.
Really impressed with the service. They responded quickly and were able to accurately detect the leak without causing unnecessary damage. Professional, efficient, and clearly experienced — would highly recommend to anyone dealing with a hidden leak.
Wayne and his colleague came and within an hour found the leak deep underneath my cellar and came up with a perfect plan which made the pipe redundant and re-routed it the following morning. An excellent option if you're having a problem with a leak you cannot find.
Called Wayne Monday and he was round Tuesday evening — came out of hours to help me out. Very professional, punctual and great with communication. Fair priced too. Will definitely recommend and use again.
Contacted them and they were at the property within an hour. Honest, well priced and gave a detailed report that will likely save me hundreds of pounds. Will definitely recommend and if necessary will use again.
Wonderful efficient service — came out the same day, nothing was too much trouble. Engineers were professional and polite, explained the problem and persevered until the blockage was cleared. Would highly recommend this company.
The staff were so professional and friendly. The technician was nice and informative — he advised me the leak was outside and wrote me a report which I sent to Thames Water. In a few days they sent a repair team and found the leak. Clear Flow are great at what they do.
I received a letter from Thames Water about high water usage. Wayne arrived on time, was so professional, guided me through what he was doing and advised me of the next steps. He also wrote me a report to send to the water board. 100% recommend.
Thermal Imaging of Your Floor
The investigation begins with a thermal imaging scan of the floor surface. A leaking underfloor heating pipe raises the temperature of the surrounding screed or concrete, and a calibrated thermal camera picks up that differential even when the floor covering is intact. We scan the entire affected zone and identify the area of elevated temperature. This gives us a defined search area before we introduce any tracer gas, which speeds up the process and reduces the likelihood of a missed fault.
Tracer Gas Confirmation
Once thermal imaging has narrowed the location, we isolate the suspect loop and introduce a hydrogen-nitrogen tracer gas mix into the pipe circuit. This inert, non-toxic gas permeates through the material above the pipe and escapes at the surface. An electronic detector traces the gas signature, and the point of highest concentration marks the exact fault location. We then mark that point on the floor so the repair contractor knows precisely where to work.
Your Investigation Report
At the end of the investigation, you receive a written report covering the fault location with coordinates referenced to fixed points in the room, the method used to identify it, photographic evidence from the thermal imaging scan, and a recommended repair approach. This report is accepted by all major UK insurers and loss adjusters. If your policy includes trace and access cover, we can liaise directly with your insurer on your behalf.
Common in London New Builds and Extensions
Underfloor heating is now common in London new builds, extensions, and renovated properties, and the pipe networks vary considerably in age, layout, and construction. Older systems using polybutylene pipe are more prone to joint failure, while newer manifold-fed systems can still develop faults at compression fittings or where the pipe has been disturbed during a subsequent fit-out. Whatever the system type, the investigation method is the same, and the outcome is a precise fault location rather than a best guess.
Underfloor Heating Leak Investigations
FAQs About Underfloor Heating Leak
Can't find what you're looking for? Call us on 0203 886 2316 and we'll answer on the spot.
What are the signs of an underfloor heating leak?
The most common indicators are a drop in boiler pressure that recurs after topping up, uneven floor temperatures, and an unexplained increase in energy or water bills. As the leak progresses, you may see damp patches on the floor surface, tiles lifting at the grout lines, or a persistent musty smell near the skirting. Because the pipework is buried, the early signs are often subtle and easy to dismiss until the damage is already significant.
How do you detect a leak in underfloor heating without lifting the floor?
We use two methods in combination. Thermal imaging scans the floor surface for temperature anomalies caused by escaping heated water, narrowing the search to a specific area. We then introduce a hydrogen-nitrogen tracer gas into the isolated circuit and detect it at the surface with an electronic probe, accurate to within a few centimetres through concrete, screed, or tile. Nothing is opened until the fault point is confirmed.
How much does underfloor heating leak detection cost?
Detection costs depend on the size of the system, the floor construction, and access requirements. We provide a fixed quote before we attend so there are no surprises on the day. Our No Find No Fee guarantee applies: if we cannot locate the source, you pay nothing for the investigation.
Can you find a water leak under a concrete or tiled floor?
Yes. Tracer gas is specifically suited to this situation. The gas permeates through solid concrete, screed, and tile grout, and a surface probe detects it at the point of escape. This gives a precise fix point, typically accurate to within a few centimetres, without breaking open any of the floor first.
Is underfloor heating leak detection covered by home insurance?
Most buildings insurance policies include a trace and access clause, which covers the cost of locating a hidden pipe fault. We provide a written report with photographs and methodology that satisfies the requirements of all major UK insurers and loss adjusters. We recommend checking your policy wording before you book, as cover limits and excess amounts vary by insurer.