The short answer
If your roof is still leaking after a repair, tell the roofer promptly and send dated photographs of the stain and of the weather it appeared in. The usual causes are a second leak source that was always there, a cause that was misread because water travels, or a repair that has not yet had a real storm to test it. A return visit to find which one it is should be your first request.
Why a roof can keep leaking after it has been repaired
Water on a ceiling is a symptom, and the roof that produced it can be a long way off. Rain that gets under a tile will run along the underlay or down a rafter before it drips, so the brown ring above your bed can be found some distance downslope of the hole. If the first visit fixed the nearest defect and missed the one upslope, the stain returns with the next downpour and looks as though nothing was done.
Gutters add to the confusion. An outlet that is blocked or a joint that has opened lets rain overshoot onto the fascia and back under the lowest course of tiles, producing a damp patch that reads as a roof fault. A look along the eaves for staining is cheap and quick, and it rules a cause in or out before anyone lifts a tile.
There is also the case where the first repair was right but the roof had two faults at once. A cracked ridge bedding and a failed chimney flashing can feed the same wet patch. Fixing one gives partial relief, which is confusing, because the leak is smaller but still there.
The four usual explanations, and how to tell them apart
Think of these as questions to put to the roofer, in roughly this order.
A second source
Does the leak appear only in particular weather, such as driving rain from one side? That points to a second entry point on a different face, such as a verge, a flashing or a gutter overflowing behind a fascia.
A misdiagnosis
Was the repair made where the water showed rather than where it entered? This is the commonest error on a loft with no lining and a long, shallow slope. Following the water from the loft side, torch in hand, tells you more than a glance from the ladder, and a hose test one slope at a time can confirm it.
An unfinished repair
Some repairs are deliberately temporary, such as a sealed slate or a tarpaulin. They stop the worst of the water but are not meant to last, and a second visit is part of the plan. If yours was temporary, say so to yourself before assuming it failed.
Condensation
Damp that forms on the rafters and beneath the covering can look like a leak and drip in cold spells without any rain. Our guide on finding a roof leak covers how it differs from water coming in.
What to record before you phone the roofer
A tidy record turns a vague complaint into a job that can be solved. Photograph the stain with a coin or tape measure beside it, and again each day it changes. Write down the date, the hour and the weather: wind direction matters as much as the amount of rain. If water drips, note whether it comes quickly or only after a long spell of wet. Put a bowl or a towel under it and mark the water level so you can see how fast it fills, and check it again after a few hours so the roofer has a rate to work with.
If the loft is safe to reach, look for wet timber, dark stains on boards and damp insulation beneath the spot, and photograph them from the hatch rather than leaning over joists. Never step between the joists in the dark, and keep clear of any wiring; water near lights is a separate issue, covered in our answer on water near light fittings.
Raising it with the roofer and what a fair response looks like
Contact the roofer in writing as well as by phone, and attach the record. Ask for a return visit to find the cause, not simply to apply more sealant on top of the old repair. A fair roofer will accept that a recurring leak is part of the original job until proved otherwise, and will look at the first repair, the surrounding slope, and the loft side together.
Where access is the stumbling block, say so. Reaching a high valley or a rear slope from a ladder is often what limited the first diagnosis, and whether a roof repair needs scaffolding is worth reading before the second visit. Weather can limit the testing too: running a hose over the roof in sections is a reasonable way to find an entry point, but the limits on working in rain still apply to any fix.
Where the guarantee comes in
A written guarantee only helps if you know what it covers, and our page on roof repair guarantees explains the usual terms. A repeat leak at the same spot normally falls inside workmanship cover, while a new leak from a part that was never touched may not.
If you are reading this as one of our customers, our workmanship guarantee runs for 10 years and is written down and we would want to see the roof again. If you are dealing with another firm, keep their quote and invoice, ask for any guarantee in writing, and give them a fair chance to return before involving anyone else. Our roof repairs page shows how we approach a survey, and you can reach us on 01453 933613 or through WhatsApp or the form.