Ridge tile and verge repairs in Bath

At the apex, the last course of tiles on each side stops short of the very top. A row of curved or angled ridge tiles is laid over the gap to close it. They shed rain away from the joint, and they hide the top edge of the tiles and the battens beneath. Battens are the thin timber strips fixed across the rafters that every tile hangs from. Nothing stands higher on the house, so the ridge is where wind pulls hardest.

Ridge tiles come in several profiles. Half-round tiles are a simple arch and are common on clay roofs. Angled ridges have two flat faces that meet at a crisp line. Segmental and hogback types suit particular tile families, and some roofs carry decorative crested or finial ends. On a plain tile roof the ridge tile is usually clay; on a concrete roof it is normally concrete in the same colour. When we repair a ridge we match the profile and the material to the tiles already on the roof, because a mismatched ridge shows from the street even when the slopes below it look right.

What holds a ridge tile on

Traditionally every ridge tile was set in a bed of sand and cement or lime mortar laid along the apex, with the joints between tiles filled and struck off. It looked simple and it lasted for years, but the bond depends entirely on the mortar. Since BS 5534:2014, a bedded ridge should also be fixed mechanically, so that the tile does not rely on mortar alone. The mortar still has a job to do: it fills the gap, keeps out driven rain and gives the tile a bed to sit on. The fixing, usually a screw or a clip to a timber ridge board or batten, is what stops the tile leaving the roof.

How a ridge fails

Mortar loses its grip slowly. Frost gets into cracks, water swells the sand, and the bed shrinks away from the tile. You will see hairline cracks along the joints, then gaps, then a tile that rocks when touched. Sooner or later a gust lifts it, and the tile slides down the slope or drops into the garden. Moss and lichen growing along the mortar line are a sign that moisture is sitting there.

The effects reach indoors in a particular way. Rain driven into an open ridge joint runs down the underlay or onto the timbers at the top of the loft, so the first sign is often a stain high on a bedroom wall or ceiling, not a drip. A leak that appears only in a south-westerly gale usually has a ridge or a verge behind it. A quick look from the ground with binoculars, from both sides of the house, will show you missing pointing, tilted tiles and gaps at the ends. Do not climb up to check; loose tiles at the top of a roof are the ones most likely to give way underfoot.

On a survey we walk the full length of the ridge, press each tile for movement, look at the mortar joint by joint, and check the ridge board or batten from the loft where we can reach it. That tells us whether the ridge needs pointing, re-bedding or a different system altogether.

If your ridge has started to shed tiles, our guide to re-bedding ridge tiles step by step sets out the order of work, and the page on ridge tile types helps you identify what you have. A single loose tile is a small repair, but it is often the first of several, so it is worth having the whole line checked while access is arranged.

Verge is the word for the roof edge that runs up the side of a gable, the triangle of wall that rises to the apex at the end of the house. Unlike the eaves at the bottom, there is no gutter here. Instead, the tiles stop at the face of the wall, and the edge has to be sealed against rain running across it and against wind pressing up under it. How that edge is finished depends on the age and type of the roof.

A traditional mortar verge has three parts. Under the edge tiles is an undercloak, a strip of plain tile, slate or board laid along the top of the gable wall so the first row of tiles overhangs it. The edge tiles then sit on that, projecting over the wall face by a small amount so rain drips clear. Finally, the gap between the tiles and the wall is filled with mortar, bedded and struck off at a slope. Some roofs add a bargeboard, a timber board fixed along the gable edge, with the tiles running over the top.

Why verges fail

The mortar line along a verge is long, thin and fully exposed. It cracks as the roof timbers move through the seasons, and it loses its grip on the tiles where moss and frost work behind it. Once the bed has gone, nothing holds the edge tiles but their own weight, and a strong wind blowing across the gable can lift a row of them together. Water then runs down the face of the undercloak and into the wall head, where it rots the timber and stains the gable wall. The first sign from outside is often a dark streak down the render or stone below the verge.

A tile that has slipped at the verge can also pull the one beside it, so it pays to deal with an open verge before the next gale. Look for gaps between the mortar and the tile, pieces of mortar on the ground, and tiles at the edge that sit at a different angle from the rest of the roof.

Mechanical fixing at the verge

BS 5534:2014 applies to the verge as well as the ridge and hip: the edge tiles should be held with a mechanical fixing, and nobody should count on the mortar to keep them there. In practice that means a clip or a screw into the batten at every edge tile, or a dry verge system. We check the fixing first, then repair the bedding. Where the undercloak has rotted or cracked, it is renewed before the mortar goes back, because a new bed over a failed undercloak will not last.

On older houses we take care over the look of the edge. A thin line of mortar, flush with the tile, reads differently from a thick cement fillet, and the difference is visible from the lane. Where the tiles are handmade clay or stone, the mortar is lime-based and the bed is kept tight.

Our page on mortar verges and how they are repaired covers the repair sequence in more detail, and the answer on the verge undercloak explains the hidden strip that sits under the edge tiles. If wind is the likely cause, the guide to wind and storm damage to ridges and verges shows what to photograph before any repair.

Dry-fix means a ridge, hip or verge held down by manufactured parts instead of mortar. A dry ridge system typically has a continuous timber or plastic ridge batten fixed to the top of the roof, a flexible roll that follows the profile of the tiles below, and a set of clips or brackets that screw each ridge tile down. The roll is often vented, which allows moist air to leave the loft along the whole length of the ridge. Joints between tiles are left open or covered by a short ridge adaptor. There is nothing to wash out or shrink.

BS 8612:2018 is the standard these systems are tested to, and it applies to dry ridge, hip and verge alike. It sets out how a system must perform under load, so a product that meets it has been tested as a complete assembly, not just as separate parts. A competent installer follows the manufacturer's instructions exactly, because the clips, screws and roll are designed as a set. A mixed set of parts from different makers is no longer the assembly that was tested.

What dry ridge does well

A dry ridge does not crack with frost or movement. It can be fitted in cold or damp weather when mortar would be risky. It goes on quickly, which reduces the time a scaffold has to stay up. If a tile is damaged later, it can be unscrewed and swapped without disturbing the rest. The ventilation roll can help to keep the roof void drier, which matters on roofs where condensation has been a problem.

Typical UK figures reported by MyBuilder (2026) put dry ridge at £40 to £60 per linear metre, and a typical installation at £500 to £1,000. Your fixed quote follows the survey, and it depends on ridge length, hips, tile profile and access.

Where it is not the first choice

The look is different. A dry ridge may leave visible gaps or a slightly different line at the joints, and some systems have a visible roll or end cap. On a plain, newer roof, this is rarely a concern. On a listed building, a conservation-area house or a roof where the mortar line is part of the character, it can be, and a mortar bed with hidden fixings is often the better answer. If the house is listed, ask B&NES before the ridge detail changes. The council, not the roofer, decides whether consent is needed.

The fit also depends on the tile. Some profiles have dry-fix parts made for them, and others do not. A handmade clay tile or an uneven stone tile may not sit properly on a standard roll. We check what the manufacturer offers for the tile before suggesting dry ridge, and tell you openly where it will not suit.

Ventilation is a point to confirm. If the loft already has other vents, a vented ridge is an addition, not a replacement.

The comparison of dry ridge and mortar bedding weighs the two against each other roof by roof, and how long a dry ridge system lasts answers the question of wear. If you are thinking about the loft side, the page on ventilated ridge systems explains what the vent does and does not do.