Do Ridge Tiles Always Need Mortar?

Ridge tiles sit along the crest, over the joint between the two slopes. There are three common ways to hold those tiles on. The first is the older method: tiles bedded on mortar with nothing else. The second is mortar plus mechanical fixings, where clips, screws or straps hold each tile and the mortar mainly fills and seals the joints. The third is a dry ridge: a batten along the top, fixings through or over it, and a roll or strip that seals and ventilates, with no mortar bed at all.

Each has its place. Mortar-only ridges still exist on a great many older roofs, and they work until the bed cracks. The other two systems are the ones now recommended for new work and repairs. A dry ridge also has no wet trade, so it can be fitted in cold or damp weather that would spoil mortar. Our page on what a dry ridge system is (the dry ridge page) shows the parts and how they fit together.

BS 5534 is the code of practice for pitched roofs covered in slates or tiles, and BSI lists the 2014 edition with its 2018 amendment as current. BSI cautions that some of it may not suit an old roof built from traditional or salvaged materials. The practical effect for ridges is that mortar is not relied upon alone to resist wind, so tiles set in a bed are expected to be clipped or screwed down as well, whether they sit at the ridge or along a hip. Marley, a tile maker, says the same about the 2014 revision.

BS 8612 sets out the tests that a manufacturer's dry ridge, dry hip and dry verge systems are put through, and it is how a maker shows a product has been properly assessed. Nothing in law forces a roofer to follow BS 5534, so a mortar ridge is not unlawful and nobody should tell you it is. It is, though, the standard a careful roofer works to, so ask which one will be used on your roof and why. A clear answer is a good sign of a clear quote.

On some roofs, mortar with fixings is the better answer. A period house with irregular, reclaimed or handmade ridge tiles may not suit a standard dry system, because the fittings are made for regular profiles. A conservation area or listed building may call for a traditional look, so check with the council's planning team before the ridge is altered, and ask your roofer to photograph the existing tiles so the new ones can follow their shape. Some owners simply prefer the finish of a bedded ridge, and on a short run with sound tiles that is a reasonable choice. The key is that the tiles are secured to the roof and not just stuck to each other, whatever the system.

If you keep mortar, the bed should still sit over mechanical fixings, be mixed correctly and be laid onto a clean, damp base. Repointing a cracked ridge costs less in the short term but does not add the fixings that older ridges lack, so the same cracks tend to return. It is a stopgap more than a cure. Our answer on cracked ridge mortar explains when repointing is enough, and the page on BS 5534 ridge and verge fixing covers the standard in more depth.

A dry ridge suits a roof of regular concrete or clay tiles where the mortar has failed more than once. There is nothing to crack, moss or fall out, and the strip beneath can help the ridge breathe. It also comes with a set of compatible fittings, such as end caps and hip trays, so the whole line is made to work together. Fitting is quicker than bedding, so scaffold time can be shorter, and there is no waiting for mortar to cure before the weather turns. That is a real advantage in a wet spring.

The ridge still needs sound timbers and tiles that suit the system, and the old mortar has to come off first. As a national guide, Checkatrade's June 2026 repair table gives £50 to £70 per metre for dry ridge, while your own figure depends on length and access. Our comparison of dry ridge and mortar weighs the two, and the dry ridge and dry verge page gives the wider picture. Photos of your ridge and its ends are all we need to begin, and the survey that follows confirms the tile type, the timber beneath and the best fixing for the roof.