The short answer
A slate roof can take a clay or concrete ridge tile, a cast or stone ridge, a slate ridge formed from slates cut to a profile, or a lead roll over a timber core. Each can be bedded in mortar or fixed dry with mechanical clips. Current standards expect the ridge to be mechanically fixed, not held by mortar alone. The right choice depends on the roof's character, its exposure and the budget.
What the ridge has to do
The ridge caps the join between the two top courses of slates on each side. It has to keep rain and wind out of that gap, allow the roof space to ventilate if the design relies on it, and stay put in a gale. It is also the most exposed part of the roof, taking the full force of wind and often the first place a roof shows age. The ridge can be as plain as a row of pressed tiles or as decorative as a run of crested clay. The choice affects the look as well as the performance, and it should suit the house.
The main ridge types
Clay ridge tiles are the traditional partner of slate in many parts of England. They come in half-round, angled and decorative profiles, in red, buff or blue-black, and are bedded in mortar and often mechanically fixed. Concrete ridge tiles are cheaper, plainer and heavier. Cast or stone ridges are rarer and found on grand or historic buildings. A slate ridge is made from slates cut and mitred to a profile, sometimes called a wrap-over or a mitred ridge, and gives a clean, all-slate finish. A lead roll over a shaped timber batten gives a slim, hard-wearing alternative that is common on good-quality or heritage work.
A dry-fix system uses a ridge board or batten, plastic or metal clips and sealing strips so the ridge tiles are held mechanically, with breathable gaps for ventilation. Our page on ridge, verge and dry-fix repairs covers these systems in depth.
Mortar or dry-fix
For many years ridges were set in a bed of mortar, and the tiles stayed up so long as the mortar did. Mortar cracks with weathering and movement, and a fallen ridge is a common storm casualty. Under BS 5534:2014 the ridge, hips and verges must be fixed mechanically, so mortar by itself is no longer relied on, while BS 8612:2018 sets the performance rules for dry-fix systems. In practice, a new ridge today is mechanically fixed with clips or screws, and the mortar, if used at all, is cosmetic.
A dry ridge has a practical advantage: it needs no bedding mortar to crack and fall, and it goes on quickly. One published guide gives £900 to £1,600 for a dry ridge on a semi-detached house, with scaffold adding £300 to £900. Your fixed quote follows the survey. Against that, a dry ridge changes the look of the roofline a little, since the end caps and sealing strips are visible, and some owners prefer the traditional bedded finish on a period house.
Choosing for a slate roof
Start with the house. A Victorian slate roof usually suits a clay ridge, often in a matching or slightly contrasting colour, while a modern home with a grey slate roof may look best with a slate or dark concrete ridge. Check the profile against the roof's pitch, because a half-round ridge looks wrong on a low roof. Consider exposure too: a roof on high ground or by an open field needs the strongest fixings. Ventilation also matters. If the roof relies on a vented ridge to remove moisture, the system must have the right airflow, which our guide on slate roof underlay and ventilation explains.
Hips, the sloping lines at the ends of a hipped roof, take similar finishes, often with a bonnet or mitred approach. See what mitred hips are.
The ridge forms part of a listed or conservation-area building's character, so a change of style may need consent, and the council's conservation officer is the person to ask.
Ridge faults to look for from the ground
You can often judge a ridge without leaving the garden. Look for tiles that sit at an angle or have a visible gap between them, bedding mortar that has crumbled and left dark lines, end caps missing from a dry system, and moss packed along the joints. Check the gutter for pieces of mortar, which are a sign the bedding is breaking up. Inside the loft, daylight along the ridge line or stains on the ridge board point to a failed seal. Early repair of loose pieces is far cheaper than replacing tiles that have fallen in a gale and taken slates with them.
We survey the ridge from the ground and, where safe, at close quarters, and take pictures of any cracked bedding, loose tiles or failed fixings. Whatever we recommend, the price is fixed in writing. Browse our other slate roof services in Basingstoke for related work.
Every roof is different. A free survey with photos settles it for yours.
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