A slate roof can work well for generations, and when it leaks the cause is usually small and local. A single slate is gone, a nail has let go, a lead strip has lifted. The skill in a repair is finding the real cause and fixing it in a way that does not damage the slates around it, since slate is brittle and a careless foot will crack one beside the slate you came to mend.
This guide takes the main repairs in turn and explains how each is carried out, what it costs on the national figures, and the point at which patching stops being the sensible choice. It is the overview; the single most common fault has its own page, why slates slip. For the wider service, see slate roofing in Stroud.
Finding the fault before touching the roof
The first look is from the pavement or garden, then from inside the loft. From outside, we look for gaps in the courses, slates sitting proud or hanging low, a slope that has gone wavy, and streaks of stained brick below a joint. From the loft, daylight through the roof, damp rafters and dark tide marks on the underlay show where water has been coming in. The wet patch on a ceiling is rarely directly below the failure, because water travels along rafters and battens before it drops.
Access is the next question. Slate cracks under a boot, so a roofer works from a ladder that hooks across the ridge or a board that spreads the load over several courses. In the lanes and terraces around Stroud, ladders and scaffold towers are often needed to reach a slope at all, and we plan that at the survey so the quote shows it. The survey photographs of your slopes go with the written quote, so the faults we describe are visible to you as well.
Why the cause matters more than the symptom
Replacing one slate that has slipped solves nothing if every nail on that slope is rusting. A survey therefore looks at the neighbouring slates, the state of the battens beneath and the age of the fixings, so the repair is sized to the problem and not to the single visible gap.
Cracked, broken and missing slates
A cracked or missing slate is the simplest repair. The damaged slate is removed by sliding a slate ripper (a flat tool with hooks) up under it to cut the nails, then drawing it out. The replacement must match the original in size, thickness and colour, so that it laps correctly and does not stand out. Our guide to slate sizes and headlaps explains why a slate that is a few millimetres short can leave too little cover.
Fixing the new slate
The new slate cannot be nailed in the usual way, because the slates above it cover the batten. Instead it is slid into the gap and held with a tingle or a hook, described below. The tail is checked for line with its neighbours, and the slate is pressed home so it sits flat.
Cost
MyBuilder's slate roof cost guide puts the national range for a single slate repair at £60 to £120, and for replacing five to ten slates at £150 to £350. Checkatrade's repair guide, updated October 2026, gives £150 to £220 per m2 for natural slate repair, ex VAT and excluding access. These are national guide figures from other publishers; the price for your roof comes after the survey.
Tingles: the small strip that holds a slate in place
A tingle is a thin metal tab, cut from lead, copper or stainless steel, that is fixed to a batten and turned up to catch the bottom edge of a replacement slate. It is the standard repair for a slate that has slid down, because the original nail hole has been torn through the head and there is nothing left to hold the slate in position.
How a tingle is fitted
The roofer slides the replacement slate into place, then nails the tingle to the batten through the gap between the courses above. The free end is then folded up and across the slate's lower edge to lock it. The strip should be wide enough to hold the slate against wind and narrow enough that it does not show as a bright line on the roof.
Tingle, hook or clip
Cupa Pizarras' summary of BS 5534 rules out hook fixings on any pitch under 25 degrees. On a shallow roof a tingle or a clip is therefore the better choice. A tingle is a repair method and not a permanent substitute for nailing: if fixings have failed across an entire slope, a run of tingles points to the nails as the true problem, which is the next topic.
Our page on slate tingles goes through the fitting in more detail.
Nail fatigue and what to do about it
Nail fatigue is the corrosion and failure of the fixings that hold slates to the battens. Iron nails rust, and the rust swells and weakens the metal until the head shears away from the shank. The slate is then held only by its own weight and the slates above it. In time it slips, often in the first strong wind after the fixing has gone.
One of the first things we check on an older slate roof is how many slipped slates there are and whether they cluster. A single slip is a repair. Slips scattered over a full slope suggest the fixings are ageing out together.
Repair or renew
Re-nailing is possible where the battens are sound and the slates are in good condition: each failing slate is lifted and fixed again with copper or stainless nails. But the work is slow and reaching the lower nails means disturbing the slates above. When the nails, battens and underlay are all tired, a strip and re-slate, in which the sound slates are reused on new battens and fixings, is cheaper than a long run of small repairs. The process is set out in re-slating a roof.
Choosing copper or stainless nails for the new fixings removes the cause of the failure, which is why we specify them on any re-nailing job.
Natural slate itself can outlast its nails by decades. MyBuilder gives natural slate a life of 80 to 100 years or more, so the fixings are the weak link.
Ridges, hips and valleys
The ridge is the capping that runs along the apex. Ridge pieces were traditionally bedded in mortar, and over time the mortar cracks and falls out, loosening the tiles. The remedy is to re-bed or replace the ridge. MyBuilder's slate guide lists re-bedding or swapping ridge tiles at £300 to £600, and £200 to £400 for repointing a ridge or hip. After BS 5534:2014 the ridge also takes mechanical fixings, and a dry-fix ridge under BS 8612 dispenses with mortar.
Valleys
A valley is the inside angle where the roof folds and two slopes drain into one run. On slate roofs it is formed in one of three ways: an open lead gutter with slate on either side, a mitred (cut and joined) slate valley, or a swept valley in which the slates curve round the corner. Valley faults are among the more disruptive leaks because the valley carries water from two slopes. Common problems are split or lifted lead, debris blocking the channel, and slates around the edge that have cracked.
Repair means cutting out the damaged section, laying new lead lapped to suit the pitch and re-laying the edge slates. Each slate along the edge is checked for hairline cracks first, because a crack that survived the strip would become the next leak, and any slate that fails the check is replaced with a matching one. Debris is cleared from the channel before the new lead goes down. Our page on slate valleys sets out the three forms and their usual faults.
Flashings and leadwork against chimneys and walls
Flashing is the lead that closes the gap where a slope meets a wall or chimney. Soakers are small lead pieces interleaved with the slates at that junction, and a step flashing is the stepped strip that runs up a sloping abutment. The lead sits in a groove (the chase) cut into the brickwork and is sealed there, so failure is usually at the top edge where the sealing has perished.
Repair often means re-dressing lifted lead and re-pointing the chase, without renewing the whole run. If the lead has split or the metal is thin, replacement is the better answer. MyJobQuote's guide puts a chimney flashing patch at £150 to £250, and Checkatrade puts lead flashing repairs at £50 to £70 per metre, with stepped flashing at £80 to £120 per metre in Code 5, ex VAT.
Lead codes
Lead is sold in codes that correspond to thickness. Code 4 is 1.80 mm and Code 5 is 2.24 mm, per Leadworx, whose view is that Code 4 suits general flashing work. MyJobQuote says correctly fitted lead flashing can outlast 80 years, so the quality of the fitting counts as much as the code.
Do not seal slate roofs with coatings, mastic or foam as a shortcut. They trap moisture, make the slates harder to reuse and are not a fix for a failing fixing.
What a slate repair quote should contain
Once the survey is done, the written quote should be itemised rather than a single lump sum: scaffold or access, labour, the slates and fixings, lead, waste removal and making good. National ranges such as those above tell you what to expect before anyone visits, and the survey turns them into a figure for your roof. Where a repair needs a scaffold, that line can be sizeable, and MyBuilder puts a full-roof scaffold at about £1,125.
Like for like
Natural slate stays natural slate. If your roof is slate, we repair it with slate that matches, not a different material that looks similar from the ground. If you are choosing between natural and man-made replacements, see natural versus fibre cement slate.
After the work
Once the repair is finished the roof is checked from the ladder and from the loft where we can, we clear the site and take the rubbish away. The repair carries a written 10-year workmanship guarantee. If the survey shows that repairs would only postpone a re-slate, we show you the photographs and leave the choice with you.