What Ridge Goes on a Slate Roof?

Where the two slopes of a pitched roof join at the summit, the line they make is called the ridge. A row of ridge tiles caps that join, each one a curved or angled piece that carries rain over the join. A clay ridge in a warm red or buff sets off blue-grey slate well, so the two read as a matched pair from the street.

Is a clay ridge right for my slate roof?

Often, yes. Somerset has a long record of making tiles. The South West Heritage Trust reports that Bridgwater's yards made bricks, plain tiles, pantiles and terracotta ornaments in variety, and a local heritage leaflet adds that ridge tiles, once called crease tiles, belonged to the same trade. A clay ridge keeps faith with the county's tile-making past, which matters when you want the roof to read as it always has. Colour is worth a look before you order, because clay varies from kiln to kiln and a ridge that is a shade too bright will show on the skyline.

The weight of a clay ridge puts a premium on good fixing, and how the ridge is held down matters as much as its looks. See our slate roofing page for the full picture. Our page on dry ridge and verge explains the alternatives to a mortar bed in plain terms.

A ridge can also be made from the roof's own stone. Slate ridges are formed by cutting slates and fixing them over the apex so the whole roof reads as one material. They suit buildings where appearance counts, such as a listed house, but they are skilled work and slower to do than a row of tiles, and the ridge slates must be cut to the pitch of both slopes. Expect the price to reflect that labour.

What is a lead roll ridge?

A roll is a length of lead dressed over a timber core along the ridge. It sheds water and can be shaped to the line of the roof. On lead, MyJobQuote says flashing can last for over 80 years, and a lead roll is cut from the same metal. Lead can stand in for a tile ridge on a slate roof, and it weathers to a soft grey. It is a different job from a clay tile, with different fixings and a different price, and it suits owners who want a low profile. We cover the metal in our lead work service.

Ridge tiles were bedded in mortar for generations. Marley explains that when BS 5534 was revised in 2014, it made plain that mortar's grip alone could no longer be counted on for ridges and hips, and a bedded tile therefore wants a clip or screw in addition. That pairing, mortar plus a clip or screw, is what you will see on a properly repaired ridge. Mortar is not banned. It is simply no longer trusted to resist a gale by itself.

What is a dry-fix ridge?

A dry-fix system holds the tiles with clips, screws and a vent strip in place of a wet bed. BS 8612 is the standard these dry systems are tested against, covering the ridge, hip and verge parts. Ask any supplier whether the system you are offered has been through it. With no mortar bed there is nothing to crack along the joint. Each maker has its own instructions, so we follow the data sheet for the product chosen. Look at our answer on slate roof vents for how a dry ridge ties in with loft airflow.

We look at four things on the survey. How old is the ridge, and is its bed cracked or loose? What do the other ridges and hips on the property look like, since a match matters on the street side? Is the building listed or in a conservation area, where the look of the roof forms part of the consent? And how exposed is the site to wind? A hilltop cottage and a sheltered terrace do not need the same fixings, and a ridge that runs the full length of a long barn will move more than one over a small porch.

Do I need consent to change the ridge?

Replacing a ridge in the same style is normally permitted development on a house. A listed house needs listed building consent too if the work would alter how the building looks, and a conservation area calls for a word with Somerset Council's planning team about any change in the style of ridge. Send us a photo of your ridge from the ground, and we will say what we would examine first once we are up on the roof.