The short answer
A dry ridge system fixes the ridge tiles to the roof with screws, clips and brackets instead of bedding them in wet mortar. The ridge is the apex of the roof, the line where the two slopes meet. A strip or roll under the tiles closes the gap and lets the loft breathe. BS 8612 is the standard these systems are tested to.
Dry ridge puts the same ridge tiles on top, held down a different way. The parts underneath are what make it work, and each can be named in a sentence.
The idea in plain words
Where two slopes of a pitched roof meet, a gap is left at the apex. Ridge tiles, the curved or angled tiles at the very top, cover that gap. For a long time they were set on a bed of mortar, which set hard and held them in place by its own weight and grip.
What does dry mean here?
It means no wet mix and no waiting for anything to harden. A dry ridge can be walked off the day it is finished, and the first shower does it no harm. A dry ridge is built from parts that are fixed in place mechanically. The tiles are held by screws, clips or brackets into a timber, so the grip comes from metal and the structure, and not from cement. If one tile ever needs replacing, it can be unscrewed and lifted without breaking its neighbours. Nothing has to cure, and nothing rigid is asked to cope with a moving roof.
Marley reports that BS 5534, in its 2014 revision, accepted that bedding on its own cannot be trusted to hold the tiles. Dry fix is one way of meeting that. Our page on dry ridge against mortar weighs up the two methods and the reasons a roofer might pick either.
The parts under the tiles
A dry ridge has a handful of components, and each does one job. Knowing them makes it easier to read a quote or a survey photo, and to ask a roofer the right questions about the job.
What holds the ridge tiles down?
A ridge batten or board is a length of timber fixed along the apex. The tiles are screwed or clipped to it, so the load goes into the roof structure. Some systems use a bracket that clamps to the batten, and others use long fixings that pass through the tile.
What is the roll or strip for?
The gap between the ridge tile and the top of the roof tiles needs closing, or rain and birds would get in. A roll is a flexible, often ribbed strip that does this, and it moulds itself to the shape of the roof tiles beneath. Many rolls are also vented, which lets damp air leave the loft, as our page on a ventilated dry ridge explains.
At each end of a ridge, a union joins it to the verge or hip. The pieces are matched to the tile profile, which is why a system for one tile will not suit another. Colour matters as well, because a grey roll under a red ridge shows from the street, so most ranges offer several shades.
Standards, testing and where you see it
BS 8612:2018 is current. Marley describes it as the specification that tests dry systems for verge, hip and ridge, so a product tested to it has been put through a set method. The data sheet lists the results, and you can ask to see that sheet before any work begins.
Is it only for new roofs?
No. Dry ridge is fitted on new builds and also used to replace a failed mortar ridge on an older house. Many of the big new estates around Taunton, Monkton Heathfield and Comeytrowe among them, have dry ridge and verge on their roofs, and for a builder with rows of identical houses the speed of fitting is an obvious attraction.
It is also used on hips, the sloping ridges that run down the corner of a hipped roof, and on verges at the gable edge. Hips and verges use matching parts, with a different union at each junction, so one system can cover the whole roof.
Is it right for your roof?
Dry fix suits many concrete and clay tile roofs, but not every one. The tile profile, the pitch and the exposure all matter, and a listed or conservation-area home may need a consent route before the finish changes. Ask Somerset Council's planning team whether that applies to you.
Is it required by law?
No. Marley says BS 5534 is not required by law, and no rule bans mortar. What the standard asks is that ridge tiles be mechanically fixed, which dry ridge does by design. Our page on whether dry ridge is a legal requirement goes through that question.
The way to know is to have the ridge looked at. We photograph the tile, the batten and the line, talk through the pictures, and explain which finish suits. The quote is a single written price covering the whole ridge. Our overview of dry ridge and verge work sets out the full approach, and a picture of your ridge, snapped from the lawn, gives us a starting point for the conversation.
More on dry ridge
Does a dry ridge look different from a mortar ridge?
From the street the tiles look very similar. Without mortar there are no hand-finished mortar lines, and the joints between tiles are cleaner. Colours are chosen to match the roof tiles, and we check a sample against your roof before ordering anything for the job.
Can birds nest in a dry ridge?
The roll or strip closes the gap beneath the ridge tiles, which stops birds and insects getting in. Where a gap is left, they can. The survey checks every end and join for gaps, and a nest found in use is dealt with in line with the law on nesting birds.
The full picture: Dry ridge and verge repairs in Taunton ยท More short answers