The mistake this page exists to stop
Most people search for water damage repair while looking at the damage, not at the leak. The ceiling is stained, the floor has lifted, there is a tide mark up the wall, and the obvious next step is to get someone in to put it back.
It is the wrong next step. Reinstating over a leak that is still running, or over a structure still holding water, is money burnt twice. Fresh plaster on a wet wall blows or stays damp-stained. A new floor laid on wet screed cups, lifts or grows mould underneath. New plasterboard on a ceiling that is still drying above will show through in weeks.
So the sequence is: dead leak, dry structure, then make good. Nothing on this page is more important than that.
Stage one: prove the leak is dead
"It stopped dripping" is not evidence. A lot of leaks appear to stop because the path the water was taking has filled, saturated, or found somewhere else to go. Intermittent leaks stop on their own, then start again the moment the shower runs or the heating fires.
Before any repair work is priced, one of these should be true:
- The failed component was replaced. A split pipe cut out and a new section soldered or fitted in. A failed valve, tap tail, waste trap or shower tray seal renewed. You can see the new part.
- The circuit was pressure-tested and held. For heating and mains pipework this is the only real proof. The section is isolated, pressurised and watched. A system that holds a test pressure for a sustained period with no drop is not leaking.
- The source was reproduced and no longer appears. For shower, bath and waste leaks, that means running the appliance the way it was being used when the damage happened — not a quick rinse — and finding nothing below afterwards.
If none of those has happened, you do not have a stopped leak. You have a leak that is not currently visible. Those are different things, and the second one is what makes people pay for the same ceiling twice.
The awkward case: two leaks
It happens more than you would think, particularly in older London flats. A fixed waste pipe and an unrelated weeping heating joint above the same ceiling look like one fix that did not work. Tell them apart by cause, not by staining: if the damp pattern changes when the heating runs but not when the bathroom is used, you have a second source. If water is still appearing after a repair, start again from where the water is coming through rather than assuming the first repair failed.
Stage two: drying, which cannot be hurried
Once the source is genuinely dead, the building has to give back the water it absorbed. That is a physical process. It moves at the speed the material, the temperature and the air will allow, and no amount of urgency changes it.
What actually governs how long it takes:
| Factor | Why it matters |
|---|
| What got wet | Plasterboard gives water up quickly. Sand-cement screed, solid brick, concrete and thick lime plaster hold it for far longer, because the water has further to travel to reach a surface. |
| How long it was wet | A burst noticed within an hour has wet the surface. A slow leak running for months has saturated depth, and depth is what takes time. |
| Whether it is trapped | Water under vinyl, under laminate, inside a floor void, or behind a tiled wall has no escape route. Until that layer is lifted or ventilated, it barely dries at all. |
| Air movement and temperature | Still, cold, saturated air stops drying. Warm moving air that is then dehumidified is what carries moisture out of the structure. |
| Ventilation | A dehumidifier in a sealed room with no air movement dries the air near it and little else. It needs fans moving air across the wet surfaces. |
We will not quote you a number of days for drying, and you should be sceptical of anyone who does before they have measured. A plasterboard ceiling and a screed floor with heating pipes in it are separated by weeks, not hours. The structure is dry when a meter says it is dry, taken at more than one point and more than one depth, and stable across readings on different days.
What tells you it is finished
Not the look of it. A surface can look dry with the material behind it still saturated. Drying is finished when a moisture meter reading has stopped falling and matches an unaffected area of the same material elsewhere in the property. Until it matches, it is still wet, and anything you fix to it is temporary.
Sealing damp up behind new finishes is a health question as well as a building one. Government guidance on damp and mould is direct that the underlying moisture source has to be dealt with rather than covered over.
Stage three: making good, material by material
This is the part most leak firms do not do. They find the leak, cut the access, fix the pipe, and leave you with a hole and a list of other trades to chase. Our handymen and builders are in-house, so the same job carries through to a finished room. This is what leak damage repair and reinstatement actually involves for each material.
Plaster on masonry
Hacked back to sound, dry masonry — usually further than the visible stain, because salts travel. The wall then has to dry before it is re-plastered. Re-skim, then a mist coat, then decoration. Plaster needs its own drying time after it is applied, before paint goes on; painting fresh plaster too early traps moisture in the new coat and shows as patchy flat spots.
Plasterboard
Wet plasterboard is usually replaced rather than dried. It loses strength once saturated, sags, and the paper face holds what feeds mould. Cut back to the nearest sound joists or studs, new board, tape, joint, skim, decorate.
Screed floors
The slowest thing in the building, and the one people most often try to skip. Screed absorbs water through its whole thickness and gives it back through one face. If there is underfloor heating in it, the circuit must be proved sound before anything is laid on top — see underfloor heating leak repair. Gentle heating can help once the leak is dead, but running a floor hard to force drying can crack screed.
Timber floors
Solid boards often recover if they dry slowly and evenly; cupping frequently relaxes. Engineered board and laminate usually do not — the core delaminates and the joints swell permanently. Joists and the underside of boards need checking and ventilating, because water sits in a floor void with nowhere to go. Do not re-lay a floor covering while the subfloor is still reading wet.
Ceilings
Anything sagging or bulging comes down; the weight of held water is what causes the collapse people are afraid of. Once down, the void above is inspected and dried before new board goes up. Insulation that got wet is removed, not dried in place. Old lath and plaster is a judgement call between patch and replace, and it is usually worth saying out loud which one you are getting.
Tiling and wet rooms
Tiles come off the affected area, the substrate is checked for damage, tanking or the waterproof layer is reinstated where it was breached, then re-tiled and re-grouted. Matching existing tiles is the common problem: on older bathrooms there is often no match available, and the honest options are a feature band, a full wall, or a full room. We would rather say that at the quote than after the tiling has started.
Signs the damage goes further than the stain
The mark you can see is the part of the damage that reached a surface. Before anyone quotes for making good, it is worth checking for the parts that have not:
- Skirting boards that have swollen, split at the joints or pulled away from the wall. Water travels along the floor and wicks up the back of the timber.
- Flooring that has lifted, cupped or feels soft underfoot a metre or more from the obvious wet area.
- Paint that bubbles, or wallpaper that lifts, without being wet to the touch. The moisture is in the plaster behind it.
- A musty smell in a cupboard or under stairs next to the affected room.
- Tide marks on the ceiling below, including in a neighbour's flat, which may show before anything shows on your side.
- Doors that have started sticking in frames near the leak.
Any of these means the quote for making good should wait for a moisture survey of the wider area. For a ceiling that is still marking, see a damp patch on the ceiling and ceiling leak repair. If the leak itself has not been found yet, that comes first: how to find a water leak in a wall covers the checks you can make before anyone attends.
Where this sits with an insurance claim
Most home policies deal with this in two parts. Trace and access covers finding the leak and making good the damage caused by getting to it. Escape of water covers the damage the water itself did. They are different sections of the same policy and they are often assessed differently.
Our leak detection visit includes a written report prepared to support a trace-and-access claim — what was found, where, how it was located, what was opened. What the insurer pays is the insurer's decision, and no one who tells you otherwise before a policy has been read is being straight with you. What we can do is give you the documentation that means the claim is not declined for lack of evidence. There is more detail in our insurance claims guides.
What we charge, and what we will tell you not to do
We work at £150 per hour, agreed before we attend, with no call-out fee. If we are there to find a leak and we do not find it, you do not pay for the looking time. Reinstatement is quoted once the extent is known, which is deliberately after drying rather than before — a quote given while a wall is still wet is a guess at how far back the plaster has to come off. Our pricing page sets out how that works.
And the part that costs us work: if you call us about damage and the leak has not been proved dead, or the structure is still wet, we will tell you to wait. It is a worse conversation than taking the booking, and it is the right one. The alternative is us doing the same room twice and you paying for it once we have both pretended the timing was fine.
