Pipe Leaks (Hidden & Surface)
Underfloor heating leaks can cause serious damage if left undetected. Learn the warning signs and how professional leak detection works.
Important: Underfloor heating leaks can remain hidden for years, causing structural damage, mould growth, and increasing repair costs. Early detection is crucial.
Warning Signs of a Leak
Continuous pressure loss
System pressure drops repeatedly after topping up, indicating water escaping.
Damp patches on floor surface
Wet areas appearing on flooring, especially in consistent locations.
Floor lifting or cracking
Tiles popping, laminate buckling, or screed cracking due to moisture damage.
Increased water bills
Unexplained increase in water usage if system is fed from mains.
Mould or musty smell
Moisture beneath flooring causing mould growth and odours.
Warm spots when heating off
Localised warm areas when system isn't running may indicate leak location.
Professional Detection Methods
Thermal Imaging
Infrared cameras detect temperature differences caused by leaking water, non-invasive.
Pressure Decay Test
System pressurised and monitored. Pressure drop indicates leak presence and approximate size.
Acoustic Detection
Sensitive microphones detect sound of water escaping, helps pinpoint location.
Tracer Gas
Hydrogen/nitrogen mix introduced to system. Gas escapes at leak and is detected at surface.
Moisture Meters
Electronic meters detect moisture levels in flooring to identify affected areas.
Common Causes of Leaks
Installation Damage
Pipes damaged during installation by screws, nails, or tools penetrating the screed.
Solution: Requires professional leak detection and repair. Damaged section must be located and repaired with approved fittings.
Poor Quality Joints
Connections made incorrectly or with substandard fittings failing over time.
Solution: Locate joint using thermal imaging or pressure testing. Excavate and remake joint with quality fittings.
Pipe Corrosion
Older metal pipes or incompatible metals causing galvanic corrosion and pinhole leaks.
Solution: May require section replacement or full system upgrade to modern PEX or PEX-Al-PEX pipes.
Structural Movement
Building settlement or thermal expansion causing stress on pipes at fixed points.
Solution: Repair leak and add expansion loops or flexible sections at stress points.
Rodent Damage
Mice or rats gnawing through plastic pipes, particularly in accessible areas.
Solution: Repair damaged section. Install rodent protection and address pest problem.
Freeze Damage
Water freezing in pipes causing expansion and splits, common in unheated extensions.
Solution: Replace damaged pipe sections. Add frost protection or insulation.
Frequently Asked Questions
Related Faults
Need an engineer?
If this guide points to a fault you would rather not tackle yourself, our REFCOM-registered, F-Gas certified engineers cover London and the M25 with 24/7 emergency callout. Engineer time is £120 + VAT per hour with a written quote before any chargeable parts are fitted. Start with the relevant service below, or contact us for a site survey.