The short answer
Replace a cracked ridge tile unless the crack is a hairline in an otherwise sound, well-fixed run. Sealant can slow water for a while, but it does not restore the tile's strength, and a split tile can fall in the next gale. A roofer lifts the tile, checks the bedding and fixings beneath, and fits a new one with proper mechanical fixing, usually within a short visit.
What a ridge tile does, and what a crack means
Where two slopes of a pitched roof meet at the summit, the join is called the ridge. Ridge tiles are the curved or angled caps that close it and stop rain entering the opening beneath. They take the full force of wind and weather, so they crack more than most tiles.
Cracks have several causes. Frost gets into small flaws and widens them over successive winters. Movement in the roof or a settling gable makes a rigid tile snap. Old mortar bedding shrinks and loses its grip, leaving the tile resting on a few high spots that act as pressure points. A heavy knock from a falling branch, a ladder head or a boot on the top finishes the job, and so does a failed fixing that lets the tile rock in the wind.
The question is whether the crack has gone through the whole thickness of the tile. A surface craze line is cosmetic. A split that you can see daylight through, or a tile that rocks when touched, is a failed tile, and water will find it.
When a sealed crack will do, and when it will not
Sealing has a narrow place. If a ridge tile has a fine surface crack, is firmly bedded and mechanically fixed, and the neighbouring run is sound, a roofer may brush on a flexible sealant as a stop-gap and keep an eye on it. That buys time while a bigger job is planned.
It is the wrong answer in several cases. A tile cracked right through will not be held together by sealant, and the two halves keep moving, so the seal tears. A tile that is loose cannot be fixed by gluing the top. Sealant also traps water if it is smeared over a gap, and moisture sitting in the joint speeds up the next failure.
Rain, frost and sunshine age sealant within a few seasons. Treat any sealed crack as a temporary measure with a date by which it needs a proper fix. A cosmetic repair sold as a cure helps nobody.
How a cracked ridge tile is replaced
The work is straightforward for an experienced roofer. The cracked tile is cut free from the bedding and lifted off. The surface underneath is cleaned, and the ridge timber and the top course of tiles are checked for rot or movement. A new tile of matching shape then goes into fresh mortar, with the joint finished neatly.
BS 5534:2014 changed the rules of thumb: the tiles on a ridge or hip are now secured mechanically as well as bedded, whether by metal fixings or by a system tested to BS 8612. So a proper replacement includes a fixing, and that is why a quick mortar dab by a general handyman does not match what a roofer provides. Our page on ridge mortar mix explains what the bedding itself should contain.
Matching deserves care, because the cracked piece may be decades old. Ridge tiles come as half-round, angled, ogee and others, and colour fades with age, so we look for a close match to the neighbours.
What the repair is likely to cost
National figures give a guide. MyBuilder's slate roof guide, updated on 21 August 2026, lists re-bedding or replacing ridge tiles at £300 to £600, and repointing ridge or hip tiles at £200 to £400. Checkatrade, in its repair guide updated in October 2026, quotes dry ridge at £50 to £70 per metre and dry hip at £70 to £100 per metre, before VAT.
These are national guide figures. What moves the figure on a single cracked tile is mainly access: a ladder is enough on a bungalow, but a three-storey house usually needs scaffolding, and that can cost more than the tile work. How many tiles are cracked, and whether the bedding beneath is sound, also play a part.
The written quote follows our survey. Whoever quotes, check that VAT and any scaffolding are covered by the total they give you.
Why one cracked tile often means looking at more
Ridge tiles are laid in a line, each bedded against the next. If one has cracked, the others share the same age, the same mortar and the same weather. Walk the ridge, from the ground with binoculars, and look for gaps at the joints, mortar crumbling out, ends that no longer line up and tiles at an angle.
Where the damage is local, a single replacement is fair. Where several tiles are loose or the mortar runs out along the whole ridge, re-bedding the full run is better value than coming back each year. Our guide to hip tile repairs deals with the angled capping that runs down the corners of a hipped roof.
A wind-blown dry verge can also point to loose edges. We treat that separately on the page about dry verge caps blown off.
Doing it yourself, and what to do now
A ridge sits at the highest, most exposed point of the house, and getting to it safely needs scaffolding or a proper roof ladder. Please do not climb up to dab sealant on it. Our page on DIY ridge tile repair explains the risks.
What you can do from the ground is photograph the ridge with a zoom lens. Note the position, whether any tile is on the ground, and whether you see staining in the loft below. If a piece has fallen, keep it, because it helps with matching.
We survey the ridge, photograph the problem tiles and send a written quote. A fix like this carries a 10-year workmanship guarantee in writing. Our ridge, verge and dry-fix service covers the whole top edge of the roof. Our number is 01793 626096, and WhatsApp or the web form reach us too.