Can you fix a roof leak from inside?

1What you can safely do indoors

The first job is to stop the water doing more harm. Put a bucket or basin under any drip, with a towel inside to quieten the splash. Shift sofas, rugs and anything electrical clear. If water is dripping from a light fitting, or plaster around a socket is wet, turn that lighting or power circuit off at the fuse board and stay away until an electrician has checked it.

A ceiling that sags or bulges with trapped water may need relief. Place a bucket underneath and make a small hole with a screwdriver at the lowest point, so the water runs out in a stream you control instead of bringing down the plaster. Stand to one side while you do it.

In the loft, move stored boxes off the damp area, and lay a plastic sheet or a tray under the drip so insulation does not soak up and sag. Wet insulation loses its value and weighs on the ceiling below.

Photograph everything, with dates. Those pictures help a roofer and, if you claim, an insurer.

2Why a repair from the loft side does not work

Roofs are built to shed water from the outside in. The tiles, slates, flashings and lead are the weatherproof layer, and the underlay below is only a second line of defence. A hole in that outer layer lets water in however the underside is treated.

Spraying foam, smearing sealant or taping over the damp patch on the underside of the roof stops nothing at source. Water finds the next route, and the substance forms a skin that holds moisture against the timber, which can lead to rot. Spray foam applied to roof timbers also complicates later surveys and sales. RICS publishes a consumer guide on it, which is worth reading before anyone offers to foam your loft.

A tarpaulin or a bag of sand can look like a quick fix, but anything fixed on a roof in poor weather needs proper access. Falls from roofs and ladders are a real danger, and we ask homeowners to stay on the ground.

3Reading the leak from inside

Inside is where you can help the most, because the stain is evidence. Notice the shape and position of the marks, the date they first appeared and the weather before. A ring that grows after every shower, a patch near a chimney breast, a mark on the wall at ceiling level, or drips only when the wind is from one quarter all narrow the possible entry points.

Remember that the stain is rarely under the hole. Water runs along rafters, battens and the underlay before it drops. A tide mark on the ceiling can sit a metre or more downslope from where it came in. That is why a flashing, valley or gutter higher up so often turns out to be the cause. Our page on why a blocked valley leaks shows one common source, and cracked mortar fillets another.

Writing down what you see, even roughly, saves time during the survey and makes the work cheaper to diagnose.

4Insurance: speak to your insurer first

If a storm lies behind the damage, ring your insurer before ordering permanent work. After Storm Eunice in 2022, the trade body for insurers advised householders to have temporary emergency repairs done to limit further damage, but only after speaking to their own insurer. Keep receipts and photographs.

When a claim is disputed, the Financial Ombudsman Service looks at the storm itself, how well the damage fits storm behaviour and whether something else might have caused it anyway. Its guidance adds that policy exclusions often cover damage that happens gradually. Which? lists a leak caused by a roof that was not looked after as wear and tear.

Nobody at a roofing firm can tell you how an insurer will decide. A clear photographic record of the cause is what we can offer, and you are free to pass it on. If you disagree with a refusal, the Ombudsman's service costs you nothing, though it expects the insurer to have replied to your complaint first.

5What happens next, and how long to leave it

Once the water is contained and the room is safe, the next step is a survey from outside. A leak stopped from indoors is only paused. The longer the covering stays open, the more the timber, insulation and plaster take up water. Can a small roof leak wait looks at what is reasonable to risk.

Our survey checks from the loft first, matching the stain to a point on the slope, then goes outside to confirm it. Stopping further water and danger comes ahead of everything else. Pictures of the fault on your own house arrive with the written quote, which shows exactly what the work is for. Where the cause is a single tile or a lifted flashing, the job is only that big. If the roof turns out to need much more, the report spells out why, and what could wait if you would rather spread the cost over time.

Everything we do is set out under roof repairs.