What it does
A dry ridge holds the ridge tiles down and keeps rain out of the apex of the roof. Each tile has its own mechanical fixing, so the ridge relies on screws and clips rather than on mortar staying stuck to the tiles.
BS 5534, the British Standard code of practice for slating and tiling, changed this. BSI says reliance on mortar bedding to resist wind uplift has been withdrawn, and Marley says that since the 2014 revision all bedded tiles and fittings should include mechanical fixings. Many systems also leave a continuous vent along the apex to help control condensation in the loft.
Where you will find it on a Yorkshire roof
BSI notes that more than half of the UK's new and refurbished roofs use dry-fixed ridge and hip systems, so you will see them on new estates and on re-tiled post-war semis and Victorian terraces. Older terrace ridges in Yorkshire were bedded in mortar, and many still are.
From the street, the ridge tiles sit in a straight line with no grey mortar at their edges. You may see a small plastic union where two tiles meet and an end cap at each gable. From the loft you may see a ridge batten held on brackets.
On Pennine stone slate and some listed buildings a mortar ridge may be kept for its traditional look.
Types and materials
- Roll-out dry ridge kit. A flexible roll runs the length of the ridge with an adhesive strip pressed onto the tiles each side. Marley's RidgeFast roll overlaps 100 mm at joints and is screwed into the ridge batten at about 2 m centres.
- Ventilated roll. Many rolls double as high-level ventilation. Glidevale states 5,000 mm² per metre for its RediRoll, the figure it gives for BS 5250.
- Unions and clamps. Marley joins each ridge tile to the next with a ridge union and union clamp.
- Mortar bed with mechanical fixings. Not a dry system, but a mortar route that can meet BS 5534, such as Marley's Mortar Bedded Security Ridge kit.
The product standard is BS 8612:2018, published by BSI on 31 January 2018. It sets performance requirements and tests for dry-fixed ridge, hip and verge systems, covering fixing resistance, weather-tightness and durability. SIG Roofing's contractor brochure lists dry fix ridge systems as a range of their own (June 2020, p.11).
How it fails and the signs
A dry ridge has no mortar to crack. Marley describes mortar joints as prone to cracking and weathering, especially where the building moves.
Dry systems have their own faults. BSI says some have had significant problems with tile security and weather-tightness, which is part of why BS 8612 was written. Signs you can see from the garden, the street or a window:
- a ridge tile sitting higher than its neighbours, or out of line;
- a gap where a union is missing between two tiles;
- the edge of the roll lifting or peeled back from the tiles;
- damp staining on the timber under the ridge, seen from the loft.
Left alone, a loose ridge tile can blow off and rain can reach the roof timbers. See our answer on roofs that rattle or bang in the wind.
Repair or replace
A single lifted tile or a missing union is a small repair. Which? puts replacing a single ridge tile at £80 to £300, including labour and materials but excluding VAT, from a November 2025 survey of 11 Which? Trusted Traders.
Changing a mortar ridge to a dry ridge is a bigger job: the ridge tiles are lifted, the old mortar cleared, the batten and roll fitted and each tile fixed back. BSI says BS 5534 covers repairs as well as new roofs, so a re-bed should be mechanically fixed too. Marley says mortar needs dry weather and 5°C to 25°C to cure, while dry fix can go on in most safe working conditions, a help in a Yorkshire winter.
Price ranges are compared in our answer on ridge re-bed and dry ridge costs, the rules in our BS 5534 guide and the work on our dry ridge, hip and verge page.
At a glance
- Also called
- Dry fix ridge, dry ridge system 7
- Code of practice
- BS 5534:2014+A2:2018 (mortar alone no longer relied on to resist wind uplift) 1
- Product standard
- BS 8612:2018, published 31 January 2018 2
- How common
- Used on more than half of UK new and refurbished roofs 2
- Ventilation
- Vented rolls such as Glidevale RediRoll give 5,000 mm² per metre 5
- Fitting weather
- Most safe working conditions; mortar needs 5°C to 25°C to cure 3
- Common fault
- Tile security and weather-tightness problems with some systems 2
Take a photo from the ground, a window or the loft and send it on WhatsApp. We will tell you what it is and whether it needs a visit. Quotes are free and itemised.
Sources
- BSI, BS 5534:2014+A2:2018 Slating and tiling for pitched roofs and vertical cladding. Code of practice (published 28 February 2018)
- BSI, BS 8612:2018 Dry fixed ridge, hip, and verge systems for slating and tiling. Specification
- Marley, Should I use mortar or dry fix for my ridge and hip tiles? (updated 27 February 2026)
- Marley, How to fix ridge tiles to a roof
- NBS Source, Glidevale Protect Fulmetal RediRoll dry fix ridge and hip ventilation system
- Which?, How much do roofers cost? (survey of 11 Which? Trusted Traders, November 2025)
- SIG Roofing, Contractor Brochure 'It's Job Done' (June 2020), p.11
General information about roofing in England, checked against the sources above when published. It is not a substitute for advice about your own roof.
