Hidden Water Leak Located Beneath a Suspended Floor in Little Chalfont
September 7, 2026A concealed mains-water leak was confirmed in a Chobham property after visible moisture damage appeared on the opposite side of a cloakroom wall. The investigation shows why leak detection should combine moisture testing, acoustic equipment and targeted access rather than relying on thermal imaging alone.
The reported problem
Significant water damage and salt deposits were visible around electrical sockets on a ground-floor lounge wall. A cloakroom was located immediately behind the affected wall, but it showed no corresponding surface damage.
Leak-detection investigation
A visual inspection and comparative moisture survey were completed in the lounge and adjoining cloakroom. The affected wall reached the moisture meter’s maximum reading of 999 REL, while approximately 250 REL was recorded at the adjacent floor covering.
Thermal imaging did not reveal a defined temperature anomaly and moisture readings in the cloakroom were not elevated. Electronic acoustic testing, however, identified the sound of pressurised water movement. The indication became strongest at the far corner of the boxed and tiled area behind the WC.
Targeted access and confirmed source
The suspected pipework was concealed within a plasterboard enclosure finished with tiles. Carefully targeted access provided a restricted initial view, but pipe insulation obscured the exact defect. Further localised access exposed an active leak from the concealed copper mains-water supply.
Once the insulation was removed, a pinhole defect was identified in the copper pipe. This confirmed that pressurised water had migrated through or around the dividing construction and into the adjoining lounge wall and floor area.
Outcome and recommendations
The defective copper section was removed and a temporary repair completed so that the water supply could remain in use. A permanent accessible repair and inspection of the surrounding pipework were recommended before the enclosure is reinstated.
The moisture-affected lounge wall, nearby floor finishes and concealed void require appropriate strip-out, professional drying and monitoring. Electrical fittings in the affected wall should also be checked before decorative reinstatement.
Why a combined investigation matters
In this case, thermal imaging alone was inconclusive. Comparative moisture readings established the severity of the water damage, while electronic acoustic testing localised the escape before targeted access confirmed the precise defect. Using several diagnostic methods helped keep the opening-up focused and proportionate.
Espy Leak Detection provides non-destructive leak detection, Trace and Access investigations, moisture mapping and insurer-ready reports across Buckinghamshire, Berkshire, Oxfordshire, Surrey, Hertfordshire and West London.
Concerned about a concealed water leak? Call 01494 311075 or contact Espy Leak Detection to discuss the symptoms and arrange an investigation.
For privacy, the precise property address, client and claim information have been omitted. This case study reflects the conditions observed during the inspection.
