Pipes freeze in two situations: an under-insulated supply or waste run in a loft, garage, or external wall during a sub-zero spell, and an exposed condensate trap on a modern combi boiler that locks the boiler out by triggering its frost cut-out. The risk is not the ice itself, it is what happens when the ice thaws. The pipe looks intact while frozen, then bursts the moment the ice plug melts and the system repressurises. A controlled, monitored thaw is the only safe way to recover service without turning a frozen pipe into a burst pipe.
We thaw with low, even heat applied along the full length of the affected run, never with a blowtorch and never from one end. The mains supply is isolated first at the BS1010 stop-tap or the external boundary stop-cock, so if a hidden split is revealed by the thaw the leak is contained. Where a frozen condensate trap has locked out a Worcester, Vaillant, or Ideal combi, we clear the trap, insulate the external run with closed-cell foam, and where the original run is non-compliant we relocate or upsize the condensate to current Building Regulations Part L geometry. After a successful thaw, the entire system is pressure-tested and walked end-to-end with a thermal camera to confirm there is no hidden ice plug still in place.
Where this service applies
- No water at any tap after a sub-zero overnight low, classic frozen supply
- Frozen condensate trap on a combi boiler, fault code locking the unit out
- Outside tap or garden supply line frozen, ice extending back into the wall
- Loft tank feed or vent pipe frozen on a traditional gravity-fed system
- Frozen waste run on a flat-roof discharge, soil stack venting blocked at the cap
- Frozen MDPE supply on a buried run where the depth is less than the recommended 750mm
- Suspected hidden burst behind a freeze, controlled thaw plus pressure test required
- Unoccupied property where the system was not drained before a cold spell
- Lead supply pipework where freeze damage may have caused a pinhole or full split
How we deliver
No surprises, no upselling. The exact path every job follows.
- 1
Isolate before thaw
Internal BS1010 stop-tap closed (and the boundary box stop-cock if accessible) so that any split revealed during the thaw is contained. Buckets and towels positioned at suspect joints. - 2
Thermal scan to locate the ice plug
Thermal imaging camera run along the suspect pipework to find the cold zone. This avoids guesswork and ensures heat is applied to the right section, typically a short length under 2 metres long. - 3
Controlled low-temperature thaw
Heat applied with a hot-air gun on low setting, warm cloths, or trace-heating tape over the full ice section, working from the open end of the run inwards so meltwater can escape. Never a blowtorch. - 4
Stage the recommissioning
Once the thaw is complete the stop-tap is opened slowly while we listen for the rush-and-stop signature of a hidden split. Pressure is held for a 10-minute drop test before any room is left unattended. - 5
Repair any thaw-revealed split
If the thaw exposes a burst we cut out the damaged section and remake the joint in copper with soldered or compression fittings, or in WRAS-approved push-fit where access is restricted. Pressure tested afresh after repair. - 6
Insulate and protect
Affected run lagged with the correct-bore closed-cell foam (19mm wall on 15mm copper, 25mm wall on 22mm copper) and any external condensate run upsized to 32mm overflow to current Part L geometry. - 7
Frost-prevention advice and trace-heat option
We walk the property looking for other at-risk runs, and where the property is unoccupied or repeatedly affected we quote for thermostatic trace-heating tape on the critical sections.