Frozen pipe thawing across London

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.

How we deliver

No surprises, no upselling. The exact path every job follows.

1. 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. 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. 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. 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. 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. 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. 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.