Two ways of finishing a ridge dominate UK roofing, and the choice between them is where most ridge quotes start to differ. One is the traditional method, where each ridge tile is set on a bed of mortar. The other is dry ridge, in which a ridge batten, a seal and metal clips hold the tiles down and no wet mortar is used at all. Each has real strengths. Mortar looks right on an old roof and suits the people who built it. Dry ridge copes better with movement and weather, and it goes on quickly. Neither is right for every roof, and the decision depends on the covering, the age of the house, how exposed the site is and whether the building is protected. This guide compares the two on those terms. It also corrects a common assumption: since BS 5534:2014, a modern mortar ridge is no longer mortar alone, because mechanical fixings are now expected on bedded tiles as well.
How each method holds a ridge tile on
Mortar bedding
The traditional ridge sits on a bed of mortar laid along the crown of each slope, on top of the final row of tiles. The ridge tiles are pressed into that bed, overlapped end to end, and the joint is struck off by hand. The mortar both fixes the tile and seals the gap beneath it. Its weakness is that mortar is rigid and brittle in tension. A roof moves a little as timbers dry and shrink, the sun heats one side, and wind pulls at the ridge, and over time the mortar cracks, lets go of the tile or falls out in pieces.
Dry ridge
A dry ridge system replaces the bed with components. A batten runs along the apex of the roof, and the ridge tiles are then fixed down to it with clips or screws. A ridge roll or seal fills the gap beneath each tile, and an end cap finishes the run. Because the tiles are held mechanically, the fixing does not depend on mortar bonding to anything. The British Standard test specification for these systems is BS 8612:2018, which covers dry verge, hip and ridge systems, and the fuller picture is on our BS 5534 page.
The practical difference is that failure shows up differently. A mortar ridge fails by cracking and falling, and you may find lumps of mortar in the gutter. A dry ridge fails more slowly, usually through a damaged seal or a corroded fixing, and what you notice first is usually a tile sitting slightly out of line.
What BS 5534 changed for mortar
It is worth being exact about the standard, because it is often misdescribed in both directions. The tile maker Marley summarises the 2014 edition of BS 5534 this way: mortar on its own can no longer be trusted, for its tensile strength, to hold ridge and hip tiles, so bedded tiles and fittings should carry mechanical fixings too.
That sentence does two things. It does not ban mortar. Mortar bedding with mechanical fixings is still a recognised way of fixing a ridge. And it means that a new ridge laid on mortar with nothing else is not what the standard expects. So the real comparison today is between mortar with fixings and dry-fix, not between mortar and dry-fix as they were once understood.
For you, the consequence is practical. If a quote offers a re-bedded ridge, ask what mechanical fixing is included. A roofer who sets the tiles in mortar and nothing more is working to the old method. And because the standard shapes how new work is done, what it means for a ridge that was bedded years ago is a matter for your building control body, not something we would tell you from the pavement.
For the question of when Building Regulations approval applies to roof work, read the Planning Portal's re-roofing page or ask your building control body.
Roof type, age and covering
The covering decides more of the choice than most people expect. A modern concrete interlocking tile roof has ridge tiles made to match, and manufacturers publish dry ridge systems for their own ranges. Fitting one is straightforward, and the result looks the same as the original. Clay plain-tile roofs, common on older houses, often have half-round or angular clay ridges that sit comfortably with either method, though the dry system must be chosen to suit the tile profile.
Natural slate roofs have their own ridge pieces, in clay, stone or slate. A dry ridge can be fitted to them, but a heavy stone ridge piece needs a system and fixings that suit its weight, and the match of colour and profile is the main concern. Stone-tiled roofs and the older Cotswold-style coverings found around Bath are harder still, because the ridge is often bespoke.
Age matters for a different reason. An old roof has timbers that may be out of true, and a ridge batten fixed to a bowed or rotten ridge board will not sit straight. If the ridge timbers are in poor condition, the work is a timber repair first and a ridge repair second, and that is true whichever finish you choose. We look at what is underneath before recommending either.
Clay tile roofs can be mixed in appearance too. Hand-made clay tiles vary in colour and size, and a ridge bedded in mortar can be dressed to follow the variation along the line. A dry system sits on a straight batten, so it suits the regular lines of modern machine-made tiles more easily. On a roof with a deliberately wavy character, that difference can show.
Lifespan and guarantees: what the sources say
The figures here need careful handling, because dry-fix lifespans are not independently published and the sources that exist measure different things. The table sets out what we can state, with each figure labelled for what it is.
| Item | Figure | What it measures |
|---|---|---|
| Mortar bedding | 15 to 30 years | Typical life reported by BestBuilders (2026) |
| Dry ridge, manufacturer | Up to 15 years | A guarantee from Marley (2023), not a lifespan |
| Dry ridge, installer | At least 10 years | Typical installer warranty per MyBuilder (2026) |
Treat the first row with caution. It comes from a single trade guide and is a range, not a promise, and a well-built mortar ridge in a sheltered spot may last longer while an exposed one may last less. The second and third rows are guarantees, which describe what a maker or installer will stand behind, and they say nothing firm about how long the system survives beyond that.
The safe conclusion is only that the two methods wear out in different ways. Mortar cracks and falls away, and the only cure is to renew it. Dry ridge relies on its seals and fixings, which can be checked and renewed without re-laying the tiles. We cover how long a dry system is likely to last on our page about dry ridge lifespan.
Weather, movement and ventilation
Exposure is the second big factor. A hill-top house in the countryside around Bath gives its ridge far more wind than a sheltered valley street does. Wind lifts ridge tiles as well as pushing on them, and the load is carried by whatever fixes the tile. Mortar relies on its bond. Dry-fix relies on clips and screws. In places where the roof is regularly battered, mechanical fixing has an obvious advantage.
Movement is the other. Roofs flex in wind, expand in sun and shrink in frost. A rigid mortar joint has no give, so it cracks along the line where the movement happens. A dry system has seals that tolerate small movement, which is one reason it is promoted for roofs on timber frames and lightweight coverings.
Ventilation is a point in dry ridge's favour that people overlook. Some systems have a vented seal that lets moist air escape from the roof space at the apex, which can help a cold roof lose condensation. Not every roof needs it, and a mortar ridge can be built with ventilation too, but a ventilated dry system is a straightforward way to add it. Our guide to ventilated dry ridge explains how it works and when it helps.
One caution: ventilation at the ridge has to work with the rest of the roof. Vents at the eaves, the type of underlay and the way the loft is insulated all affect how air moves. A vented ridge fitted without regard to those can do little. We check them together when we look at a roof.
Appearance, heritage and cost
On a plain modern roof the two methods look almost the same from the ground. On a period roof the difference is visible. Bedded ridges have a handmade look that dry systems rarely match, particularly on old clay or stone, and a ridge that forms part of a listed building may be best kept in mortar, with concealed fixings added. For a listed house, B&NES Council decides whether a change to the ridge needs listed building consent, so ask before work is planned, since work without consent is an offence. Lime mortar can still be used with mechanical fixings, a pairing described on the lime mortar ridge page.
On cost, the only sourced national figure is for dry ridge: MyBuilder (2026) reports a typical range of £40 to £60 a linear metre, with a whole installation usually between £500 and £1,000. We have no sourced per-metre price for mortar re-bedding, so a direct comparison on price is not possible from published data. In practice the labour is the larger part of both, and the final difference often comes down to access and how many tiles must be replaced. The money side is broken down on our ridge repair cost page.
For a quick steer, mortar with fixings tends to suit old, listed or hand-made roofs where look matters most. Dry ridge tends to suit modern tile roofs, exposed sites and roofs where speed and fewer repeat visits matter. The survey is how that general rule is checked against your own ridge, and where a roof falls between the two descriptions we set out both options with their prices so you can choose. Ridge work is a small part of the whole roof, so it also makes sense to read it alongside the rest of our ridge, hip and verge repairs service, and to look at hips and verges while the scaffold or tower is up. A repair to the repointing alone is covered in our answer on repointing ridge tiles.