I closed the stopcock and water is still pouring out. Why?

Because the burst is upstream of that valve, on the buried supply pipe between the boundary and the house, or the stopcock is not sealing. The external stopcock in the pavement box outside the property controls the whole supply and needs a water company key. If you cannot reach it, your water supplier can shut the supply off at the boundary.

Is a repair clamp good enough?

As an overnight measure, sometimes. As a repair, no. A clamp relies on a rubber pad compressed against a pipe that has already failed once, and it will not survive the pressure cycling behind a wall or under a floor. We remove clamps and replace the section.

Can you thaw a frozen pipe instead of replacing it?

A frozen pipe that has not split can be thawed gently — warm cloths, a hairdryer on low, working from the tap end back. Never a blowtorch, and never heat applied fast, because that cracks the pipe and can ignite the joist it is notched into. The problem is that you often cannot tell whether it has already split until it thaws and starts running.

My burst pipe is in a communal riser. Who pays?

Generally the party responsible for that pipe under the lease rather than the flat it is running through, which is usually the freeholder or the managing agent. The thing that resolves it quickly is documentation: what failed, where, and what it damaged, written down at the time. That report is part of what we do.

Will you replace the floor you take up?

Yes. Reinstatement is in-house — boards, screed, tiling, plaster and decoration. The opening we make is the opening we close, and it is priced as part of the same job rather than passed to another trade.

Repairs

Burst Pipe Repair in London

Close the stopcock and open the kitchen cold tap: if the flow slows the split is inside the house, and if it does not the burst is on the buried supply pipe outside — either way the failed section is cut out and replaced, and the opening made to reach it is put back by us.

An emergency leak visit to a London home

What the job includes

Isolation and proper drain-down of the affected section
Diagnosis of whether the burst is internal, communal or on the private supply pipe
Trace work where the split is hidden in a floor, wall or ceiling void
Cut-out and replacement of the failed section — a permanent repair, not a clamp
Inspection of the rest of the run for further splits before closing up
Refill, re-pressurisation and a held test with the access open
Pipe insulation to the repaired run where freezing caused the failure
In-house making good: floors, screed, plaster, ceilings, tiling and decoration

No find, no fee · £150 per hour. The rate is fixed before we attend and does not rise for a difficult property, an awkward access or an evening visit. The total depends on how long the job takes; the rate cannot change.

Shut it down in this order

Internal stopcock, clockwise. Under the kitchen sink, in the hall cupboard, under the stairs, or where the supply rises through the floor. In flats, check the airing cupboard and behind the bath panel.
Kitchen cold tap open. This drains the rising main. Within a minute or two the flow should fall away. If it does not, the burst is upstream of your stopcock on the buried supply pipe, and only the external stopcock in the pavement box will stop it.
Heating burst? Boiler off, valves closed. A sealed system holds a finite amount of water. Closing both valves on the affected radiator or isolating the circuit stops the loss and keeps the rest of the house warm.
Lighting circuit off if water is anywhere near a ceiling rose or a downlight.
Drain a bulging ceiling from below with one hole over a bucket rather than letting the whole board come down.
Photograph before you clear up. Then start moving what can be moved and lifting what cannot.

The full symptom walkthrough is on what to do with a burst pipe.

Why pipes burst in London, specifically

Freezing

Cold snaps do the damage in the places heating never reaches: the loft of a Victorian terrace where the tank and its feeds were lagged decades ago and the lagging has slumped off, the run to an outside tap that was never isolated for winter, pipework in an unheated garage or side return, and the exposed section in a converted loft above the insulation line rather than below it. Water expands as it freezes and splits the pipe wall, but you often do not find out until the thaw, when it starts flowing again. If your water stopped during a freeze and has not come back, the pipe is frozen and possibly already split — thawing it aggressively with a blowtorch is how people set fire to joists.

Corrosion

Copper that has spent forty years notched into a joist with damp timber against it corrodes from the outside as well as the inside. Aggressive water chemistry, stray currents and old flux residue produce pinholes that open into splits. Once one appears on a run, the rest of that run is the same age and in the same condition.

Lead

A great many pre-war London properties still have a lead supply pipe from the boundary to the house, under a front path or garden that has since been paved, extended over or parked on. Lead is soft: it work-hardens, it deforms under load, and it splits along the top of the run. It also cannot be sensibly patched, because the section either side is in the same state.

Ground movement and building work

London clay shrinks and swells with the seasons, and basement digs, side returns and rear extensions put loads on shallow supply pipes that were never designed for them. A burst that appears a few months after building work usually has a cause somewhere in that work.

Pressure and water hammer

A banging pipe when a tap or a washing machine valve closes is a shock wave hitting fittings repeatedly. It loosens compression joints and fatigues push-fit connections, and the failure appears at a joint rather than mid-run.

What we do on site

Confirm isolation and drain the affected section down properly, rather than working on a pipe that is still charged.
Establish whether the failure is inside, in a communal riser, or on the private supply pipe outside. Those are three different jobs with three different owners.
Locate the split. A visible burst is straightforward. A burst that has soaked a floor or a ceiling without showing itself gets the same trace treatment as a hidden leak: pressure test, thermal, acoustic, moisture mapping, tracer gas where needed.
Open access at the located point only.
Cut out the failed length and replace it. Not a repair clamp — a clamp is a way of getting through a night, not a repair, and we will say so if one has been fitted before we arrived.
Inspect the rest of the run while it is open. A single freeze split often has a second one a metre away that has not let go yet.
Refill, pressurise, hold and watch the joint before anything is closed.
Make the opening good.

Repair or re-run

We will tell you which of these you have, and we will not sell you the larger job if the smaller one is right.

Situation	What we recommend
Single freeze split on otherwise sound copper	Cut out and replace the split section, then insulate the run properly so it does not happen again next winter.
Second or third pinhole on the same copper run	Replace the run. Patching a pipe that has failed repeatedly means paying for access again in a few months.
Burst lead supply pipe	Replace in MDPE from the boundary to the house. Lead does not take a patch.
Push-fit joint blown out	Remake the joint properly with the insert seated, and check the rest of the joints on that run, because they were all made by the same hands on the same day.
Burst in a communal riser	Isolate, document, and report to the managing agent or freeholder. We can carry out the repair where you have the authority to instruct it.

The mess afterwards, which is ours to fix

A burst does two kinds of damage: the pipe, and everything the water and the access went through. We have handymen and builders in-house, so both halves are one job. Lifted boards relaid and the finish floor made good, cut screed filled and levelled, plasterboard replaced and skimmed, ceilings repaired and repainted, tiles cut in and grouted, skirting refitted, decoration finished. You get a repaired pipe and a room you can use, not a repaired pipe and a list of other trades to chase.

Preventing the next one

Lag every pipe in the loft, the garage and any unheated void, and make sure the lagging actually closes around the pipe rather than sitting next to it.
Fit and use an isolation valve for the outside tap, and drain it before winter.
If you leave a London flat empty over Christmas, leave the heating on a low frost setting rather than off.
Learn where your stopcock is and turn it fully off and on once a year, so it is not seized on the night you need it.
If pipes bang when a tap closes, get it looked at before it fatigues a joint.

Terms

£150 per hour, agreed before we attend and unchanged for a difficult property, an awkward access or an evening visit. The total depends on hours and materials — the rate is fixed, the job length is not, and we will give you our read on likely duration once we have seen it. No find, no fee on detection: if we cannot find the leak, you do not pay for the time spent looking. A written report for a trace and access claim comes with the job; see insurance claims for what an adjuster will want from you.

Frequently asked

I closed the stopcock and water is still pouring out. Why?: Because the burst is upstream of that valve, on the buried supply pipe between the boundary and the house, or the stopcock is not sealing. The external stopcock in the pavement box outside the property controls the whole supply and needs a water company key. If you cannot reach it, your water supplier can shut the supply off at the boundary.
Is a repair clamp good enough?: As an overnight measure, sometimes. As a repair, no. A clamp relies on a rubber pad compressed against a pipe that has already failed once, and it will not survive the pressure cycling behind a wall or under a floor. We remove clamps and replace the section.
Can you thaw a frozen pipe instead of replacing it?: A frozen pipe that has not split can be thawed gently — warm cloths, a hairdryer on low, working from the tap end back. Never a blowtorch, and never heat applied fast, because that cracks the pipe and can ignite the joist it is notched into. The problem is that you often cannot tell whether it has already split until it thaws and starts running.
My burst pipe is in a communal riser. Who pays?: Generally the party responsible for that pipe under the lease rather than the flat it is running through, which is usually the freeholder or the managing agent. The thing that resolves it quickly is documentation: what failed, where, and what it damaged, written down at the time. That report is part of what we do.
Will you replace the floor you take up?: Yes. Reinstatement is in-house — boards, screed, tiling, plaster and decoration. The opening we make is the opening we close, and it is priced as part of the same job rather than passed to another trade.

Problems this repair solves

I have a burst pipe