- BS 5534 is the British Standard code of practice for slating and tiling. The current edition is BS 5534:2014+A2:2018.
- Since 2014, ridge and hip tiles must be mechanically fixed with screws, clips or a dry fix system. Mortar on its own is not a fixing.
- Every interlocking (single-lap) tile needs at least one fixing, and tiles at the eaves, verges, ridge and abutments need two.
- A compliant ridge is dry-fixed or screwed and clamped. A mortar-only ridge cracks within a few winters and has to be re-bedded again and again.
What BS 5534 is
BS 5534 is the British Standard code of practice for slating and tiling. It sets out how tiles, slates, ridges, hips, verges and underlay should be fixed so that a roof stays on in the wind and keeps the water out. Roofers, manufacturers, Building Control and insurers all refer to it. The current edition is BS 5534:2014, amended in 2015 and again in 2018, which is why you will see it written as BS 5534:2014+A2:2018.
Most homeowners have never heard of it. Most roofing disputes in England come down to it.
What changed in 2014
Before 2014, ridge and hip tiles were traditionally bedded in sand and cement mortar and that was considered adequate. The 2014 revision recognised what every roofer in Yorkshire already knew: mortar is not a fixing. It cracks, it lets go, and ridge tiles come off in storms. The standard changed in three ways that matter to you:
- Ridge and hip tiles must be mechanically fixed. Screws, clips or a dry fix system. Mortar can still be used for appearance and weathering, but it cannot be the only thing holding the tile on.
- Every single-lap tile must be mechanically fixed. Single-lap means interlocking tiles, the large concrete tiles on most post-war houses. Each one now needs at least one nail or clip, whereas older practice nailed only every few courses.
- Perimeter tiles need two fixings. Tiles at the eaves, verges, ridge and abutments, where the wind gets under them, need two fixings each.
The standard also tightened the requirements for underlay, because a roof's underlay has to resist wind uplift too, and the 2018 amendment clarified how dry-fixed ridge, hip and verge systems should perform, referring to a companion standard, BS 8612.
What it means for your roof
If you have a roof re-covered today, every tile should be fixed and the ridge should be screwed or dry-fixed. If a roofer proposes bedding the ridge in mortar alone, they are proposing work that does not meet the current standard, and if it fails, you will find that insurers and Building Control take the standard's side.
For repairs to an existing roof, the position is that where ridge or hip tiles are re-bedded or replaced, they should now be mechanically fixed too. Re-bedding in mortar alone simply restarts the failure clock.
A roofer can bed a ridge in mortar for weathering, but the tiles must also be mechanically fixed to meet BS 5534. A quote that proposes mortar as the only fixing is quoting for work that does not meet the standard. Ask them how the ridge tiles will be fixed. If the answer is mortar, that is your answer.
What a compliant ridge looks like
You can check your own ridge from the pavement.
- Dry ridge. A roll or strip of ventilated material sits under the ridge tiles, colour-matched to the roof, and each ridge tile is held by a clamp between it and the next, screwed down to a batten along the ridge. From the ground you see a straight ridge with a thin band beneath the tiles and no mortar.
- Mechanically fixed and bedded. The ridge tiles are bedded in mortar for appearance but each one is also screwed or clipped to a ridge batten. From the ground it looks like a traditional ridge, but the fixings are what hold it.
- Mortar only. Ridge tiles sitting on a bed of mortar and nothing else. Cracks along the joints within a few years, then movement, then a tile in the garden.
The same applies to hips (the sloping external corners on a hipped roof) and to verges (the edge of the roof at a gable). Dry verge units clip over the edge of the tiles and remove the mortar that always falls out of a verge.
Why mortar fails in Yorkshire
Mortar shrinks as it cures. The roof moves as it heats and cools. Rain gets into the hairline cracks, freezes and opens them. Within three to five winters a mortar-only ridge is visibly cracked, and once cracked it holds water rather than shedding it. Re-bedding it is a few hundred pounds every few years for the rest of the roof's life. A dry ridge is fitted once.
What Roofline fits
Roofline fits dry ridge, hip and verge systems as standard on new roofs and re-roofs, and mechanically fixes ridge tiles on repairs. Every interlocking tile is nailed or clipped and perimeter tiles get two fixings. It is not a premium option. It is what the standard requires and it is priced into every quote. See our dry ridge, hip and verge page.
This guide is general information about roofing in England and is not a substitute for advice about your own roof. Standards and regulations are updated from time to time; check the current edition before relying on a specific requirement. Written by Roofline, roofers in Barnsley. Last reviewed September 2026.
