Pitched roof leak repair starts with a question that sounds simple: where is the water actually getting in? On a tiled roof the answer is rarely straight above the stain. Rain that slips past a cracked tile lands on the underlay, a membrane fixed beneath the battens that acts as the backup barrier, and runs downhill until it finds a nail hole, a tear or a badly lapped joint. From there it can follow a rafter or soak along a roll of insulation before it ever marks the plaster.
Tiled roofs around Taunton come in many profiles: concrete interlocking tiles, pantiles, small clay plain tiles and the Double Roman, a wide interlocking tile that Bridgwater's yards once turned out alongside bricks and ridge tiles. Each one lets water in at its own weak points. This post walks through those places in turn: slipped and cracked tiles, tired underlay, valleys, abutments, chimneys, ridges and verges. It covers what you can check safely from the garden and the loft, what typical UK repair figures look like, and what to do on the evening the drip starts.
Why the drip is rarely below the fault
Picture a tiled roof as two layers working together. The tiles shed nearly all the rain. Behind them, the underlay catches whatever is blown or drawn past and carries it down to the gutter. Battens, the horizontal timber strips the tiles hang on, are nailed through that underlay into the rafters. Water inside the house means both layers have let it through at once, and the two openings can sit well apart from each other.
How far can water travel before it shows?
Further than people expect. A trickle that gets past a cracked tile near the top of a slope can run down the underlay, pass several battens, then drip off where the sheet sags or has torn lower down. Once it reaches a rafter it may track sideways along the timber, or soak into the loft insulation and spread out before it finds the ceiling below. The stain you can see is simply the spot where the water ran out of road.
Why does the stain move after each storm?
Wind changes the way rain strikes the roof. A south-westerly gale pushes water up under the laps of tiles on one slope, while a soft easterly shower might not get in at all. If the patch only appears in certain weather, keep a note of the date, the wind direction and how hard it rained. Those notes narrow the search before anyone sets up a ladder, and they help us decide which slope, valley or chimney to open up first when we arrive to look.
Reading the loft before anyone climbs
Much of the detective work can be done from inside, and it is far safer than a ladder. Choose a dry day soon after rain, take a good torch, and only step on the ceiling joists or on boarding. Your foot will go straight through plasterboard between joists.
Stand roughly above the ceiling stain and look up. You are hunting for tide marks on the underlay, dark streaks running down a rafter, damp or flattened insulation, and rusty nail heads where the battens are fixed. Follow any streak uphill with the torch. Where it starts is the area we will check from outside. On older roofs with no underlay at all, you may see the back of the tiles directly, and a cracked or slipped one can show as a thin line of daylight.
Photograph what you find with your phone. Pictures taken in the loft are a big help to a roofer and to your insurer if you need to make a claim.
Is it a leak or condensation?
Condensation can look like a leak, so rule it out early. It tends to show as droplets spread over a wide area of underlay, worst on cold mornings, and it appears whether or not it has rained. A leak follows the weather and leaves one trail. Older bitumen felt and modern HR underlay are both non-breathable, so a cold loft under them depends on airflow at the eaves. On a cold roof where HR underlay sits beneath a pitch above 15 degrees, Marley gives "10mm along the length of the eaves" under BS 5250. Our guide to felt, breathable and HR underlay explains how each type behaves.
Slipped, cracked and missing tiles
A tile that has moved is the simplest leak to find and usually a small job to put right. Stand back from the house, ideally with binoculars, and scan each slope row by row. Look for a tile that has dropped below those beside it, a hole in a course, a lighter edge where a corner has snapped off, or pieces of tile in the gutter.
Why do tiles slip in the first place?
Old nails rust through, battens soften and split, and frost can crack the nibs that hook each tile over its batten. Our answer on why roof tiles slip goes through each cause. A single slipped tile on a sound roof is a quick repair. A whole slope of them creeping downhill points to failing fixings behind, which is a bigger conversation.
Does a cracked tile always leak?
Not straight away. An interlocking concrete tile with a hairline crack can shed a summer shower for months, then let water through the first time a gale drives rain into it. Our piece on whether a cracked tile is an emergency helps you judge how quickly to act.
Replacing a tile means lifting or easing the ones above, sliding a matching tile into place and fixing it so the wind cannot lift it. On older clay roofs, finding a match is the hard part. We keep sound salvaged tiles where we can, because a mismatched profile can leave a gap water will find.
Typical UK range for replacing roof tiles (MyJobQuote, Oct 2026): five tiles £150 to £200, with an average of around £215; ten to twenty tiles £200 to £275. Access and the tile profile move the figure.
Valleys, abutments and chimney flashings
Where a roof changes direction or meets masonry, it relies on lead, mortar or a formed channel instead of overlapping tiles. Those joins take more water than any open slope, so they deserve a close look.
What goes wrong in a valley?
A valley forms on the inside corner between two slopes and channels the rain off both. Lead valleys split at the joints or creep down over the years; tiled and mortar-bedded valleys crack and lose their bedding. Leaves and moss also dam the channel, so water rides up under the tiles at its sides. A full roof valley replacement has a typical UK figure of around £540 (MyJobQuote, Sep 2026), though a clearing and re-dressing can be all a sound valley needs.
How do lead soakers and flashings fail?
An abutment is any line where the roof runs into a wall, such as a two-storey house beside a single-storey kitchen. There, soakers (small pieces of lead tucked under each course of tiles) sit under a flashing, a strip of lead dressed down over them and wedged into a mortar joint in the brickwork. Lead is graded by a code number that reflects thickness; Royston Lead lists code 3 for "soakers only" and code 4 and up for flashings. Lead itself "can last for over 80 years", so when a flashing leaks we look hard at the pointing it sits in and how it was dressed.
Chimneys gather every one of these joins in one place, plus the flaunching, the mortar collar that seals the chimney pots into the stack. Typical UK chimney leadwork runs from a £150 to £250 patch to £350 to £920 for a full set (MyJobQuote, Sep 2026).
Ridges, verges and tired underlay
The ridge runs along the summit of the roof under a row of capping tiles, while a hip is the angled external corner where two slopes join. A verge is where the tiles finish along the slanting edge beside a gable wall. On older Somerset roofs, all three were traditionally bedded in mortar, and that mortar cracks, shrinks and washes out over time. Once it goes, rain blown across the roof can run straight in at the top or edge.
Can a ridge still be bedded in mortar?
Yes. Mortar is not banned. Marley explains that the 2014 revision of BS 5534 stopped treating a mortar bed on its own as enough to hold ridge and hip tiles down, so bedded tiles now get mechanical fixings as well. A dry-fix system, which fixes ridge, hip or verge tiles using clips and caps in place of mortar, is the other route; BS 8612 is its test specification. Typical UK ridge work comes in between £225 and £550 (MyJobQuote, Oct 2026), and a dry verge system is typically £500 to £2,000 (MyJobQuote, Oct 2026).
When is the underlay the real problem?
Sometimes the tiles are fine and the sheet behind them has given up. Old bitumen felt can turn brittle, tear where it sags between rafters and rot away at the eaves above the gutter. A few loose tiles over that kind of felt will keep leaking even after they are refixed, because nothing behind them catches the water. If the loft shows perished underlay right across a slope, we will say so, and talk you through whether stripping and re-tiling that slope is the better buy. For scale, MyJobQuote puts a full re-tile of an 80m² roof at £3,000 to £8,000 (Oct 2026).
Making it safe, then putting it right
When water is coming through, the first job is limiting the damage. Put a bucket under the drip and move furniture and rugs out of the way. If the ceiling is bulging or water is near a light fitting, keep everyone out of that room and switch off the lights on that circuit at the consumer unit. Please stay off ladders and the roof itself in wind or rain; nothing up there is worth a fall.
What happens on an emergency visit?
First, the leaking roof is made safe. That might mean refitting a slipped tile, a temporary patch over a split valley, or a weighted sheet across a damaged area until the weather allows a proper repair. Our emergency and general roof repairs page sets out how that visit works. For a guide to the outlay, MyJobQuote gives a typical UK emergency call-out of £150 to £300 (Oct 2026).
Who should I tell first, my insurer or a roofer?
Your insurer comes first; after that, set up the temporary repair so the damage cannot spread. Keep photos of the ceiling, the loft and the roof, and keep every receipt. Whether a policy pays depends on its wording and the cause, so read your cover before assuming either way.
Once the roof is weathertight, we come back to look properly. We go up, find the cause, and show you pictures taken on your own roof, where the slipped tile, the split lead or the perished felt is plain to see. You can read more about how we approach pitched roofing work across Taunton and the villages around it.
Before you ring about a leak
Can a leak be fixed with sealant instead of new tiles?
Sealant smeared over a tile can hold for a season, but it traps water behind the laps, stops tiles lifting cleanly later and does nothing for torn underlay or a split valley. We would rather swap the broken tile, re-dress the flashing or refix the ridge, so the roof sheds water the way it was laid to.
What does a leak that only shows in gales mean?
Rain pushed sideways by a strong wind gets under tile laps, verges and flashings that stay dry in a straight downpour. A leak that appears only in gales often points to a verge, a ridge, a lifted flashing or a tile sitting slightly proud. Note the wind direction each time, because it tells us which slope to start on.
Will a temporary repair affect my insurance claim?
Telling the insurer first and then stopping further damage with a temporary repair is the order to follow, so the patch itself is part of the right response. Keep photos from before and after, and every receipt. If you and the insurer are unable to agree, the Financial Ombudsman Service handles complaints, and using it costs nothing.
More on this subject: Pitched roofing in Taunton
