Roof leak: what to do now, common causes and repair costs
What to do in the first hour of a roof leak, how to tell it from condensation or a burst pipe, the common causes, 2026 repair prices and what home insurance covers.
A roof leak needs two things fast: the water caught and the electrics made safe. Then a roofer has to find where it gets in. Most leaks come from slipped tiles, failed lead flashing or a split flat roof, and most repairs cost £150 to £1,200 in 2026. We cover the first hour, how to tell a leak from condensation, the causes and their prices, insurance, and when to replace instead.
What to do if your roof is leaking
Deal with the water inside first and the roof second. None of these steps needs a ladder against the house or a foot on the roof.
- Make the electrics safe. If water is near a light fitting, a socket or the consumer unit, switch the electricity off at the consumer unit if you can reach it safely. Electrical Safety First's flood advice is to leave lights and appliances in the wet area off until a registered electrician has checked them, and never to touch exposed wires.
- Catch the water. Put buckets or bowls under every drip with towels around them, and move furniture, electronics and rugs out of the wet area.
- Release a bulging ceiling. A ceiling bulging with water is holding it in. Put a bucket underneath and pierce the lowest point with a small screwdriver so it drains in a controlled way rather than all at once.
- Check the loft. With a torch, find where the water comes in, put a tray or bucket under the drip and mark the spot for the roofer. Stand only on the joists or boards.
- Photograph everything. Take photos and video of the ceiling, the loft and anything damaged before you clean up, then ring your insurer before booking a permanent repair.
- Clear what you can reach from the ground. A gutter or downpipe overflowing onto the wall is worth clearing if you can reach it safely. Anything higher is the roofer's job.
- Get the leak covered. A roofer's temporary visit to fit a tarpaulin and secure loose tiles costs £150 to £400, and it buys time to get a proper quote.
Stay off the roof. Walking on a pitched roof, climbing a ladder in wet or windy weather, working lead and brushing sealant on in the rain are all jobs for a roofer.
Surface damp that lasts more than 24 hours can start to grow mould, so dry the room as soon as the water stops: heating on, windows open and a dehumidifier running. One from around £100 that removes at least 5 litres a day earns its place in the week after a leak.
Is it the roof? Signs of a leak and the look-alikes
The signs that point to the roof are a water stain in the loft or on an upstairs ceiling, damp patches, slime or moss on the outside walls, and mould or a musty smell in a top-floor room. Water can run along a rafter or the felt before it drips, so the stain may show some way from the gap it came through.
Droplets spread across the felt and beading on the nails are condensation in the loft, and the fix is air moving through the roof space, not a roofer. Water coming through the ceiling below a bathroom or a cold water tank is more likely a pipe than the roof, so the stopcock and a plumber come first.
| What you see | Most likely cause | The giveaway |
|---|---|---|
| One wet patch on an upstairs ceiling | Roof leak | Same place every time, and it follows rain |
| Droplets across the underside of the roof and on the nail tips | Condensation in the loft | Worst on cold mornings, whatever the weather did |
| A stain below a bathroom or a water tank | Pipe or tank leak | Shows when water is used, or all the time |
| A damp patch high on an outside wall | Overflowing gutter or penetrating damp | Follows heavy or wind-driven rain |
Common causes of a roof leak
Where a roof lets water in depends on the type of roof you have. A pitched tiled or slate roof fails at its tiles and at the joints between them: the ridge, the valleys, the verges and the lead around chimneys and walls. A flat roof fails at its membrane, its seams and its outlets.
| Cause | Where the water shows | Usual repair | Price |
|---|---|---|---|
| Slipped, cracked or missing tiles or slates | Under the damaged patch, worse in wind-driven rain | Replace 1 to 5 tiles | £150 – £400 |
| Failed lead flashing at a chimney or wall | Around the chimney breast, or where the roof meets a wall | Repoint or replace the flashing | £150 – £800 |
| Cracked ridge mortar or loose ridge tiles | Along the line of the ridge, often in the loft first | Repoint, re-bed or fit a dry ridge | £30 – £120 per metre |
| Worn valley lead or cracked valley mortar | Where two roof slopes meet | Re-line the valley in lead or GRP | £50 – £150 per metre |
| Cracked verge mortar or a poor dry verge | At the gable end, down the top of the wall | Repair the verge | £30 – £60 per metre |
| Blocked or overflowing gutters | High on an outside wall, or inside at the eaves | Clear the gutter and reseat the joints | £80 – £220 |
| Split, blistered or lifted flat roof membrane | The ceiling under the flat roof | Patch or seam repair | £150 – £500 |
| Damaged underlay under the tiles | Drips in the loft with no broken tile in sight | Lift the tiles and patch or renew the underlay | Priced after inspection |
| Badly fitted roof window, vent or fixings | Around the roof window frame or the vent | Re-seal or re-flash the window or vent | Priced after inspection |
Age sits behind many of these. Ridge mortar re-bedded today lasts 15 to 25 years and a felt patch on a flat roof 3 to 7, so an older roof starts leaking at its joints. Storms, overhanging branches and tradespeople working on the roof break tiles that were sound the day before.
Chimney leaks
A chimney lets water in through its flashing, the lead that seals the join between the stack and the roof, or through cracks in the stack itself. Repointing existing flashing costs £150 to £350 and re-flashing one chimney £400 to £800. A full re-flash, with stepped flashing, apron and back gutter, costs £800 to £1,500.
Flat roof leaks
A flat roof leaks where its membrane has split, blistered or pulled away at an edge, or where water ponds behind a blocked outlet. The water can travel under the covering before it finds a way through, so the drip does not always sit under the split.
A patch on felt costs £150 to £350, an EPDM seam repair £200 to £400 and a crack in GRP £250 to £500. Re-covering a small section of up to 10 m² costs £500 to £1,200. A patch is the right call while the damage is confined to one place, the felt is under 15 years old or the EPDM or GRP under 25, and the repair comes to less than 20% of the cost of replacing a flat roof.
Once water still stands on it 48 hours after rain, or each patch is followed by a new leak somewhere else, the covering has worn out.
Roof leak repair costs in 2026
Most roof leak repairs cost £150 to £1,200 in 2026. A few slipped tiles or a short run of flashing is half a day's work. Replacing flashing, re-bedding a ridge or repairing a valley takes 1 to 2 days, and rotten timber or several faults at once move a repair past £1,200.
| Repair | Price | Time on the roof |
|---|---|---|
| Minor: a few tiles, a small flashing fix, a gutter seal | £95 – £400 | Half a day |
| Medium: flashing replaced, ridge re-bedded, valley repaired | £400 – £1,200 | 1 – 2 days |
| Major: structural timber, a large section re-covered, several faults | £1,200 – £3,000+ | 2 – 5 days |
| Temporary weatherproofing visit | £150 – £400 | One visit |
| Scaffolding, where the repair needs it | £400 – £1,200 | Up for the length of the job |
Tile and slate replacement prices
The material sets the price of replacing tiles, and natural slate costs the most at every size of job.
| Tiles replaced | Concrete | Clay | Natural slate |
|---|---|---|---|
| 1 – 5 | £150 – £250 | £200 – £350 | £250 – £400 |
| 6 – 15 | £250 – £450 | £350 – £550 | £400 – £700 |
| Over 15, a large section | £450 – £800 | £550 – £1,000 | £700 – £1,500 |
Emergency repairs and scaffolding
An emergency repair costs 20% to 50% more than the same job booked in advance, because of the urgency and the out-of-hours work. On a £400 repair, that makes it £480 to £600.
Scaffolding adds £400 to £1,200 where the roofer cannot reach the repair safely by ladder, and £400 to £800 on a tile replacement. It can turn a £250 tile repair into a £650 to £1,050 job, so ask whether it is needed before accepting a quote.
Roof repair prices by region
Labour is the part of the price that moves with the postcode. A roofer's day rate runs £150 to £220 in the North and £180 to £250 in the Midlands, against £250 to £350 for a roofer in London. Repair prices in London and the South East sit 15% to 30% above the national average.
Can you fix a roof leak yourself?
From the inside, for a day or two, yes. Buckets, a tray in the loft, towels and a gutter cleared from the ground all keep the damage down. The repair itself is a roofer's job, and these four are the ones to leave alone:
- Walking on a pitched roof: tiles and slates crack under a foot, so a look around can add to the repair.
- Ladders in wet or windy weather: the ladder is the danger even when the fix at the top is simple.
- Leadwork: flashing is cut, shaped and dressed into place, and badly fitted flashing is itself a cause of leaks.
- Patching a flat roof: the patch has to be the right material for felt, EPDM or GRP.
Call a roofer the same day when the ceiling is bulging or cracking, the leak is growing or has appeared in a second room, or you can see from the ground that a storm has moved tiles. Where water has reached the electrics, a registered electrician needs to check them too.
Does home insurance cover a roof leak?
Home insurance usually pays when a specific event damaged the roof: a storm, a fallen tree, flying debris or tiles torn off in high wind. It does not pay for a roof that has worn out, was poorly maintained or failed gradually, and a failed flat roof membrane usually counts as wear.
Ring the insurer before any work beyond keeping the weather out. Most policies want photographs of the damage and more than one quote before the permanent repair starts, and receipts for the tarpaulin visit belong with the claim.
Repair or replace the roof
Repair while the fault is local: a few tiles, one flashing, a single leak. Replace once repairs stop being occasional. When repairs over a rolling five years add up to 30% to 40% of a full roof replacement, replacing is the better value, and a pitched re-roof costs £4,000 to £20,000 on most UK houses.
A roof that needs £800 of repairs every year has cost £4,000 after five, the price of re-roofing a small terraced house. The other sign is how much of the roof is failing: once more than 25% to 30% of the tiles are damaged, replacing usually works out cheaper over the long run than repairing them one leak at a time.
Does a roof repair need building regulations approval?
In England, most roof repairs need no approval. The government's building regulations guidance exempts most repairs and maintenance, but lists replacing the covering on a pitched or flat roof as work that needs approval. A few tiles or a length of flashing is a repair. Stripping and re-covering the roof is a replacement, and a roofer on a competent person scheme that covers the work can self-certify it.
- Wales runs its own building regulations. Welsh Government guidance says re-roofing needs approval in most situations, while some flat roof repairs need no application.
- Scotland uses building warrants. Replacing a covering in whole or in part with material of the same general type needs no warrant under Schedule 3 of Scotland's building standards, but the work still has to meet the standards. The council's building standards team confirms where a job sits.
- Northern Ireland has its own building control, run by the district councils. Its Technical Booklet F1 counts replacing a flat roof's waterproof membrane as renovation, but not a patch repair.
Common questions
What should I do if my roof is leaking?
Catch the water, move your belongings and switch off the electricity at the consumer unit if water is near lights or sockets and you can reach it safely. Photograph the damage, ring your insurer and get a roofer to fit a tarpaulin over the leak, which costs £150 to £400. Stay off the roof yourself.
How much does it cost to fix a roof leak in the UK?
Most roof leak repairs cost £150 to £1,200 in 2026. Replacing a few slipped tiles costs £150 to £400 and re-flashing a chimney £400 to £800. Scaffolding adds £400 to £1,200 where the roofer needs it, and rotten timber or several faults at once push a repair to £1,200 to £3,000.
Is it normal for a roof to leak a little?
No, a roof should keep out all water, and a small leak is a fault that grows. Droplets across the underside of the roof on cold mornings are usually condensation, and the fix there is ventilation. A patch that appears in the same place after rain is a leak and needs a roofer.
Does house insurance cover roof leaks in the UK?
Home insurance usually covers a roof leak caused by a specific event, such as a storm or a fallen tree. It does not cover a roof that has worn out, was poorly maintained or failed gradually, and a worn flat roof membrane usually counts as wear and tear. Photograph the damage and tell the insurer before any permanent repair.
Why does my roof only leak in heavy rain?
A roof that leaks only in heavy rain has a small gap that wind-driven rain reaches and light rain does not. The usual causes are a slipped tile, lifted lead flashing, cracked ridge mortar, or a gutter or valley that cannot carry the volume and backs up under the tiles. Note where it drips and the wind direction so the roofer can find it in dry weather.
Do roof leak sealants work?
A leak sealant or roof paint is a stopgap that keeps water out until a roofer comes, not a repair. Even a proper felt patch on a flat roof lasts only 3 to 7 years, against 30 to 50 years for new lead flashing on a pitched roof. Brushing sealant on in the rain, or from a ladder in wind, is a job to leave to a roofer.