Slate roof ridge
What ridge goes on a slate roof?
The short answer
A slate roof is usually finished with clay or other ridge tiles, a rolled lead ridge, or a dry-fix ridge system, chosen to suit the roof and the street. Whichever you pick, the ridge should be mechanically fixed. Ever since BS 5534 was revised in 2014, a mortar bed has been treated as a seal and a bedding, not as the thing that keeps these tiles on, so a bedded ridge is fixed mechanically as well.
The ridge options that suit a slate roof, how each one is held on, and what to check when you compare quotes.
Why the top line of a slate roof needs its own covering
At the crown of the roof the topmost row of slates on each side stops short of the apex. That leaves a gap, and the ridge covering closes it. Hips need the same treatment. A hip is a sloping external corner of a roof, where two faces meet and shed water in different directions. Slates cannot cover either, so a separate component has to.
It has hard work to do. It takes the wind that rushes up the slope and over the top, it sheds water to both sides, and it must stay put in a gale. When a ridge fails, rain goes straight into the roof space, so the survey begins here, from a ladder or another safe vantage, with photographs of whatever turns up. Loose joints are easy to miss from the road, so the line and both ends get a close look.
Clay, concrete and lead: the usual choices
Ridge tiles come in clay or concrete, in half-round, angled and other profiles. Clay in a colour that suits the slate is a traditional pairing and a sensible choice where the aim is to keep the old character of the house. Concrete ridge tiles are available too, though they sit differently against natural slate and weather in a different way.
Lead is the other route. A rolled lead ridge is formed from sheet over a timber core, and it is used where a finer line is wanted or where tile profiles do not suit the roof. It needs careful detailing at the ends and where hips meet it. Which covering is right depends on your roof and your street. Our guide to Victorian slate roofs shows how stacks, ridges and verges work as a set on a tall terrace, and the slate roofing page covers the wider job.
Bedded in mortar or dry-fixed: how the ridge stays on
A traditional ridge is bedded in mortar. That seals the joints well, but Marley advises mechanical fixings on any bedded tile or fitting as well, since mortar's own grip is not something to depend on any more. Mortar still has its place as the bed. It just does not carry the load by itself.
A dry-fix system holds the ridge tiles with clips, screws and a ventilated roll or strip, without a bed of mortar. BS 8612:2018 is the standard that systems of this kind are tested against. With no mortar there is nothing to crack and fall out, which is the main attraction. The price turns on how long the ridge is and how easy it is to reach, so it is worked out once the roof has been seen. Neither method is right for every roof, and the survey decides which suits yours.
Keeping the ridge in step with the street
Slate roofs often sit in streets where the skyline matters. Arun's appraisals for The Steyne and Aldwick Road want the original materials back where they were lost, and they treat the chimney stacks as features that shape the roofline. A mismatched ridge undermines both, and neighbours notice. A replacement ridge in the wrong colour or profile shows up from the pavement.
If your home is listed, works that affect its special character need consent, so ask the council before changing the ridge. In a conservation area, the council's conservation officer can advise on what suits the street. Our guide to slate roofs in a conservation area lists the questions to put first. We can match the profile and colour to what is already on your roof, and show you samples of the options before an order is placed.
Signs that the ridge needs attention
From the ground, run your eye along the ridge. A wavy line, a tile standing higher than the rest, or a gap with daylight showing means something has moved. Crumbs of mortar by the back door or in the downpipe shoe suggest the bed is breaking down, and a drip in the loft near the top of the roof often traces back to the ridge.
You do not need to go up. A photograph taken with a phone zoom is enough for a first opinion, and the survey that follows confirms it. If only a few tiles have shifted, a refix could cover it, and we would suggest only that. Where the whole length has failed, a fresh bed and fixings or a new system is the better answer, with the written quote giving a single total. See our slate roof repair guide for the neighbouring repairs.
Related questions
Ridge fixings
Is a slipped ridge tile an emergency?
It can be. A loose tile may fall in the next gale, and the gap lets rain in. If a tile has shifted, keep clear of the ground below it and phone us. Leaks and storm damage take priority with us. The first job is a temporary measure that stops the water, and the lasting repair is planned once the roof is dry enough to work on.
What should a ridge quote say about the fixings?
It should say whether the ridge is bedded with mechanical fixings or dry-fixed, name the ridge product, and describe how the ends and hips are finished. If a quote only says ridge tiles refixed, ask how they will be held, because the old habit of trusting the mortar bed alone has gone.