Flat Roof Repair London | Leak Repairs

Right now

Three things worth doing before anyone arrives

Deal with the inside first. Something under the drip and something absorbent around it saves the floor as well as the ceiling. Anything electrical near the wet area, a fitting or a hatch above it, is a reason to turn that circuit off.
Photograph the ceiling, with the date showing. How fast a stain spreads cannot be reconstructed afterwards, and the same shot taken again a week later settles more than a paragraph about it ever will.
Stay off the roof while it is wet. It is slippery, and on an older covering there is no telling from up there what will take your weight.

The rest of it is in what to do in the first hour of a leak.

The short answer: Most leaking flat roofs are repairable. What decides is not how big the leak looks but the state of the boarding beneath it: dry boarding takes a localised repair, while boarding saturated over years will hold nothing laid on it.

Services

What we repair

Most leaks come from a handful of causes. We repair all of them:

Splits, cracks and punctures in felt and other membranes (the waterproof covering itself)
Blistering and lifting where layers have lost their bond
Failed laps (the overlapping seams between sheets) letting water track under the membrane
Cracked or lifting upstands (the turned-up edges at walls), flashings and edge details
Leaking junctions around vents and pipe penetrations (anything passing through the roof), and around rooflights and their kerbs, which fail on their own terms
Blocked or failed outlets (the roof's rainwater drains), and standing water that never clears
Overflowing gutters and tired fascias, soffits and gutters that soak the roof edge
Storm damage, including wind-lifted coverings, where the record of what happened matters as much as the repair
Crazing, cracking and blown surfacing on an asphalt roof, which fails by hardening rather than by splitting
Opening welds, punctures and shrinkage on single ply, TPO and EPDM, where the sheet usually outlives the seams that hold it together
Weeping laps, tired fasteners and corroding gutter lines on a profiled metal roof, which leaks at its joints long before the sheet gives up
Water arriving in the flat below from a balcony or a terrace, where the waterproofing sits under whatever people walk on

The system on your roof changes the repair rather than whether one is possible. We lay felt and liquid ourselves and mend the rest in a way that is compatible with what is already there, which is why the first question on site is always what the covering actually is. Where the answer turns out to be that the covering is finished rather than faulty, you will hear that instead, and what the deck beneath it is doing becomes the next question rather than an afterthought.

The process

How we diagnose a leak

We read the whole covering, never the damp patch alone. That means the membrane surface, every upstand, lap and penetration, the outlets and the evidence indoors, because a leaking flat roof rarely leaks where the water shows up inside. Water can enter at one point and appear somewhere else entirely, which is why guesswork is expensive.

We trace the fault to its source, explain what has gone wrong in plain English, and carry out a repair designed to last, not a patch that fails at the next downpour. You get a clear explanation of what we found, photos of the problem, and a written price for the fix before any work starts.

Repair, overlay or replace?

Not every tired roof needs stripping. Where the covering is broadly sound, a patch or an overlay, a fresh waterproof layer laid over the old one, can add years of service for a small share of what replacement would take. If the roof is beyond sensible repair, we will say so and price the options honestly. Either way you will know exactly where you stand.

The repair

How we repair

What goes on the roof

Our core repair system is torch-on felt. It is bitumen sheet bonded down in layers: tough, proven and compatible with most existing flat roofs. At upstands, edges, penetrations and anywhere a flame has no business being, the work is closed in cold-applied liquid waterproofing, which is what that material exists for.

Homes and blocks alike

We repair flat roofs on homes, extensions and garages as well as commercial and residential blocks. For property managers we can combine a repair visit with a wider roof condition survey, so one call-out answers the bigger question too: how long has this roof got? Garages fail in an order of their own, beginning at an edge nobody ever looks at, so they have a page to themselves.

After you call

What happens when you report a leak

Three things make the first reply useful: where the water is showing inside, when it started or last got worse, and how the roof is reached. A picture of the ceiling helps, and one of the roof if there is a safe window to take it from. What to do while you wait for that reply, indoors and before anybody climbs anything, is set out in the first hour of a leak.

You get an answer, usually within one working day, saying what we think is happening and what we need to see to be sure. We do not price a repair from a description: the figure follows the inspection and is written down before any work begins.

Distance shapes that reply as much as anything. Leaks in the borough we work out of and the ones immediately around it can usually be seen soonest, while an address out at the far side of the A20, across the Earlsfield and Southfields terraces or over toward the south-western river bend is planned into a run rather than squeezed in.

Temporary protection, and when it earns its place

When water is actively coming in and the forecast is against us, a holding measure can keep the inside dry until the real repair is possible: a sheet dressed over the failed area, a blocked outlet cleared, a split sealed to get through the next front. It buys time rather than fixing anything, and we say which of the two we have done.

Questions

Frequently asked questions

How do you find the source of a flat roof leak?

By reading every part of the covering, not the damp spot alone. Water can enter at a split, a failed lap or a cracked upstand and travel a long way under the membrane before it shows inside, so we check the surface, every detail and penetration, and the outlets before recommending a repair.

Can a flat roof be repaired, or does it need replacing?

Most flat roofs can be repaired if the deck (the boards under the covering) and the insulation are still dry. Localised splits, blisters and failed details can be patched with felt or made good with liquid-applied waterproofing. Replacement earns its place only once water has got into the build-up itself, or the covering has given up everywhere at once rather than in one spot.

What is ponding water, and is it a problem?

Ponding is rainwater that has not cleared roughly two days after the last downpour, the interval the British Standard code of practice for flat roofs, BS 6229, uses to define it. It usually points to blocked outlets or a deck that has sagged over time. On its own it is not always a defect, but it speeds up wear at laps and details, so persistent ponding is worth investigating.

Do you work for both homeowners and businesses?

Yes. Homes, extensions and garages on one side; blocks, estates and trading premises on the other, for the agents, landlords and in-house teams responsible for them. Same crews, same reporting, across South London and Greater London.

How much does a flat roof repair cost?

It depends on the size of the fault, the access and how the roof was built, so we do not publish flat rates. Every repair starts with an inspection and a written price agreed before any work begins, so you know the cost up front. Pricing a repair is free: nothing is charged for coming out, looking and putting a figure in writing. A visit becomes chargeable only when its product is a written report rather than a quotation: a full condition survey, a pre-purchase report, a dilapidations assessment or a storm report for an insurer. That fee is agreed beforehand and set against the works if you proceed.

Got a leak? Tell us what is happening

Send us a few details and a photo if you have one. We will come back to you with next steps.

Coming out and pricing the work is free; a written condition survey carries a fee, agreed before the visit and taken off the price of the work if you go ahead.

Flat Roof & Leak Repairs Across London