My radiator is leaking from the valve. Can I just tighten it?

An eighth of a turn on a nut is worth trying once. Beyond that you are crushing an olive into a pipe that has already been compressed, and the usual outcome is that a weep becomes a spray while you are out. If an eighth of a turn does not stop it, close both valves and leave it.

There is rust on the radiator and water beading on the panel. Can that be patched?

No. A bead forming on the panel means the steel has perforated from the inside, and there is no repair for that — the radiator is replaced. It is also a signal about the system water, so it is worth checking the inhibitor level and looking at the other radiators at the same time.

Will you have to drain the whole system?

Not always. Many valve and tail repairs can be done with the unit isolated locally, which saves the refill, the vent and the inhibitor. Where the valve itself has to come off the pipe, or where the leak is below the floor, a drain-down is usually unavoidable, and the inhibitor is replaced afterwards.

Water is appearing on the floor near the radiator but the valves are dry. What is it?

Most likely the tail or a buried joint under the floorboard, corroded where the pipe passes through damp timber. It cannot be assessed from above, so the board has to come up. That is also the case that leaves a stain on the ceiling below in a flat.

Do you put the floor back afterwards?

Yes. Flooring, plaster, skirting and decoration are all in-house, so the board we lift is the board we relay and the chase we open is the chase we fill. That is part of the job rather than a separate trade you have to arrange.

Repairs

Radiator & Valve Leak Repair in London

A drip at a valve is a gland, a nut or an olive and is usually a short repair; a bead forming on the radiator panel itself is corrosion working outwards and can only be replaced — and if the water is arriving from under the floor, the tail has failed and the board has to come up.

Flooring and plaster being made good after a leak repair

What the job includes

Every radiator, towel rail and valve in the property checked, not just the reported one
System pressure check to rule out a second, concealed loss
Local isolation and drain-down where possible to avoid a full system refill
Gland repacking, valve replacement, olive and tail nut remake, or blanking plug reseal
Corroded radiators and towel rails replaced where the panel itself has perforated
Floor lifted where the failure is at the tail below floor level, and the run inspected
Refill, full vent, re-pressurisation, lockshield rebalanced and inhibitor replaced
Making good in-house: flooring relaid, chases filled and plastered, decoration finished

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.

Work out which of the five it is

Almost every radiator leak is one of five things, and you can narrow it yourself in two minutes with a dry tissue. Dry everything thoroughly, then run the tissue around each point in turn and watch where it marks.

Where it wets	What it is	Scale of repair
Around the valve spindle, under the head	Failed gland packing or O-ring in the valve	Repack or replace the valve head or body
At the nut where the valve meets the radiator	The tail nut or its fibre washer	Remake the joint, renew the washer
At the nut where the valve meets the pipe	Compression olive on a scored or moved pipe	Remake, or cut back and refit a new olive
At the top corner, around a small plug	Bleed valve or blanking plug seal	Reseal or replace the plug
A bead on the panel itself, often with a rust bloom	Corrosion perforating the panel from the inside	Replacement radiator — this cannot be repaired

The last row is the one people waste money on. A radiator that has rusted through from the inside is telling you about the water in the system, not about the radiator. Sealants and stop-leak additives will buy weeks at best, and they clog the rest of the system doing it. If one panel has gone, look at the others, and look at whether the system has inhibitor in it.

The symptom pages go further into each pattern: a radiator leaking from the valve, a leaking radiator generally, and a leaking towel rail.

What to do right now

Close both valves. The thermostatic or wheel head turns clockwise to zero. The lockshield at the other end takes a small spanner or an allen key on the spindle under the cap — count the turns as you close it so it can be reset to the same balance afterwards.
Put something under it and get a towel around the wet joint. Heating water is dirty, and it stains carpet, timber and plaster permanently within hours.
Do not over-tighten. The instinct is to put a spanner on the nut and pull. On an old compression joint that crushes the olive further into a pipe that has already been compressed, and a weep becomes a spray with nobody home.
Watch the boiler gauge. Radiator leaks are system losses, so the pressure will fall. If it drops out of the band the boiler will lock out.

How the visit runs

Every radiator, towel rail and valve in the property is checked, not just the one you called about. On an older system where one valve gland has failed, the others are the same age.
The system is checked for pressure loss overall, because a radiator weep and a concealed pipe leak can be happening at once and the visible one gets blamed for both.
The affected unit is isolated and drained locally where the repair allows it, or the system is drained down where it does not. Draining locally saves you the refill, the vent and the inhibitor.
The repair is carried out — gland repacked, valve replaced, tail renewed, olive remade, plug resealed, or the radiator swapped.
Where the leak is at or below floor level, the board comes up and the tail and pipework under it are inspected properly. A tail that has corroded at the point it passes through the floor is a common find and cannot be assessed from above.
Refill, vent every unit in the property, re-pressurise, and rebalance the lockshield to where it was.
Inhibitor is replaced if the system has been drained.
Floor, decoration and any damaged plaster are made good.

What London properties throw up

Victorian and Edwardian terraces

Microbore systems from the 1970s and 1980s with copper tails dropping through suspended timber floors. The tail corrodes where it passes through the board or where it has sat in damp. Under the board there is frequently an old compression joint from a previous repair, and that is the point that finally goes. Column radiators fitted for period effect often use valve arrangements that need specific parts rather than whatever is on the van.

Purpose-built blocks

Solid floors, so tails come out of the wall instead of the floor and the pipework is chased and plastered over. A leak behind the plaster shows as a damp patch on the wall below the valve rather than as a drip. Bathroom towel rails in these flats are a standing problem: they run hot, they are often the last thing on the circuit, and pinholes appear in the horizontal tubes.

Converted flats

Retrofitted heating with long horizontal runs above the ceiling of the flat below, so a failed tail in your bedroom appears as a ceiling stain in someone else's living room. Those two calls come in separately and are one job.

Anywhere with a communal system

Where the heating is communal you may not be able to isolate or drain without the managing agent, and pressure is not yours to control. We will establish that before starting rather than after.

The part nobody else does: the floor and the wall

Getting at a failed radiator tail means lifting flooring, and getting at a chased pipe means opening plaster. Every other firm hands that back to you. We have handymen and builders in-house, so the boards go back down and the engineered wood, laminate or carpet over them is relaid, the chase is filled, plastered and made flat, the skirting is refitted, and the decoration is finished so the wall matches. Heating water also stains: where a leak has marked plaster or timber, the staining is sealed before it is painted, because it bleeds through otherwise.

When you do not need us

A radiator that is cold at the top is air, not a leak. Bleed it.
A radiator cold at the bottom is sludge, not a leak. That is a flush or a power flush.
A TRV head that has stuck often frees off by pulling the head and pressing the pin under it. No water involved.
A tiny weep at a nut you have never touched will sometimes stop with an eighth of a turn, no more. If it does not stop with that, stop turning and call someone, because the next eighth is what floods the room.
A radiator you want moved or replaced for decoration is not a leak job, and you will pay less for it as planned work.

Terms

£150 per hour, agreed before we attend, the same for an evening or weekend visit and the same for a difficult property. The total depends on hours and parts — a valve gland and a radiator replacement are not the same job, and neither can be priced before it is seen. No find, no fee applies to the detection work: if we do not find the leak, you do not pay for the time spent looking. A written report for a trace and access claim is included where there is damage to claim for. See pricing.

Frequently asked

My radiator is leaking from the valve. Can I just tighten it?: An eighth of a turn on a nut is worth trying once. Beyond that you are crushing an olive into a pipe that has already been compressed, and the usual outcome is that a weep becomes a spray while you are out. If an eighth of a turn does not stop it, close both valves and leave it.
There is rust on the radiator and water beading on the panel. Can that be patched?: No. A bead forming on the panel means the steel has perforated from the inside, and there is no repair for that — the radiator is replaced. It is also a signal about the system water, so it is worth checking the inhibitor level and looking at the other radiators at the same time.
Will you have to drain the whole system?: Not always. Many valve and tail repairs can be done with the unit isolated locally, which saves the refill, the vent and the inhibitor. Where the valve itself has to come off the pipe, or where the leak is below the floor, a drain-down is usually unavoidable, and the inhibitor is replaced afterwards.
Water is appearing on the floor near the radiator but the valves are dry. What is it?: Most likely the tail or a buried joint under the floorboard, corroded where the pipe passes through damp timber. It cannot be assessed from above, so the board has to come up. That is also the case that leaves a stain on the ceiling below in a flat.
Do you put the floor back afterwards?: Yes. Flooring, plaster, skirting and decoration are all in-house, so the board we lift is the board we relay and the chase we open is the chase we fill. That is part of the job rather than a separate trade you have to arrange.