What is vertical slate hanging, and how does it age?

Slate hanging is a cladding. Slates are fixed to timber battens on a wall, usually over a layer of breather membrane, in overlapping courses so that rain runs down the face and drips clear at the bottom. You see it on the cheeks of dormer windows, on the upper storey of some Victorian and Edwardian houses, on bay window tops, gable ends and on parts of buildings that take a lot of weather.

The term "dormer cheek" means the two side walls of a dormer, between the window and the main roof slope. These are small areas, and they are often clad in slate, lead or tiles to match the roof. Because the cheek meets the roof at a sharp angle, the junction needs lead soakers and flashing, and that junction is where most problems start.

On a roof, gravity and the overlap keep water moving out. On a wall, the slate hangs almost straight down, so water runs off easily and the headlap can be much smaller. Cupa's guidance on natural slate headlap gives 50 mm at 85 degrees pitch, compared with 115 mm at 20 degrees on a roof, which shows how little overlap a vertical face needs. Check the product's own data sheet, since the figure depends on slate size and exposure.

The slates are usually fixed with two nails each, though the exact method varies. On gables and cheeks, the bottom courses and edges take the most wind, and some builders use clips or copper nails in those spots. At corners and openings, slates are cut and often mitred or lapped, and lead is added as a backing. Our guide to how long a slate roof lasts covers the same material on the roof.

Every course should start above a drip or a lead apron, so water leaves the wall and does not run behind it.

Hung slate fails in three common ways. First, the nails corrode or the slates crack, so a few slip and leave a gap. Second, the membrane behind the slates tears or perishes, and the wall behind becomes damp. Third, the lead or soaker at the junction with the roof lifts or splits, and water gets behind the cladding.

Because the surface is vertical, a slipped slate on a wall can be spotted from the pavement, which helps. What is harder to see is the damage behind it. Water behind hung slate can rot battens and soak the wall or timber frame without showing a stain inside for a long time. If you spot damp inside near a dormer cheek, a bay or a gable, the cladding is a good place to look.

See our page on slipped slates for the roof version of the same problem, including why they slide.

Repair depends on the cause. A few cracked slates are swapped from a ladder or scaffold, cutting the old nails and sliding new slates into place. Patches of corroded fixings are a sign that more slates will come loose, so we check the neighbours, not just the visible gap.

Lead around dormer cheeks needs a closer look. The lead that runs up the side of the dormer, called a soaker, is slid under the slates in each course. If the lead is cracked, thin or the wrong thickness, it is replaced with new lead sheet, normally a code suited to flashings. Code 4 is the lead weight Leadworx recommends first for general flashing work.

If the battens and membrane are damaged, the cladding has to come off in that section. We lift the slates, check the timber, renew what has failed and put the slates back, replacing any that break. Matching slates matters on a wall because the whole face is visible. Our page on slate in conservation areas covers like-for-like repair where the building is protected.

Hung slate is rarely a place for solar panels, since panels mount on roof slopes, but fixings that go through the slates on a dormer or on an adjacent slope can disturb nearby hung slate. Our page on solar panels on slate explains how the fixings work and what to watch for.

Scaffolding matters on walls as well as roofs. A dormer cheek is often high and awkward, and the cladding runs down to the roof edge. MyBuilder's scaffolding guide, updated in August 2026, quotes around £850 to £1,200 for an ordinary two-storey house, so the scaffold can cost more than a small repair.

If you want to change the wall cladding, for example to replace slates with a different material, speak to Swindon Borough Council's planning team first. Changes to external appearance can need permission, and conservation areas and listed buildings have extra controls.

We start with photographs, taken from the ground and from scaffold or ladder where it is safe, covering the cladding, the junction with the roof and any lead. We propose whatever cures the cause with least disturbance. That might be three slates and a soaker, or it might be stripping the cheek and rebuilding it. You get the reasoning and a written price once the survey is done.

Workmanship is covered for ten years, in writing, and the site is left clean. The slate roofing hub covers our other slate work. To book, phone 01793 626096 or message us, naming the wall or dormer and the number of floors.