Anyone pricing a slate roof meets the same problem quickly. Two quotes for the same house can sit thousands of pounds apart, and the per-square-metre figure in a cost guide rarely matches either of them. The reason is that the figure covers the slate and the labour to fix it, while the real bill also carries access, the condition of the timbers underneath, the lead around chimneys and valleys, and whether the roof needs to be stripped back to the rafters.
This guide gives the published national ranges for Welsh, Spanish, reclaimed and fibre-cement slate, then works through what changes the total on a typical Swindon house. Nothing here is a Skyline price. Our own figure comes later, once the roof has been surveyed and photographed, and it arrives in writing as a single total. If you are still weighing materials, our guide to Welsh against Spanish slate covers the quality side of the choice.
The published ranges, slate by slate
MyBuilder's slate roof cost guide, updated on 21 August 2026, puts a slate re-roof at roughly £100 to £180 per m² installed. That is a wide band, and it splits cleanly by origin. The figures below come from the same page and describe typical UK jobs, not Swindon quotes.
| Slate type | Typical installed price | Typical life quoted |
|---|---|---|
| Welsh natural slate | £140 to £180 per m² | Regularly over a century |
| Spanish natural slate | £100 to £130 per m² | 75 to 100 years |
| Reclaimed slate | £110 to £150 per m² | Depends on the slates salvaged |
| Synthetic or fibre-cement | Priced on survey | 30 to 50 years |
Checkatrade's slate guide (body text dated September 2026) allows a far wider spread for natural slate, anything from 50 to 200 years, with most easily lasting over 100. Treat every lifespan as a typical range. Exposure, fixings and upkeep decide what a particular roof actually does.
What a Swindon terrace does to the sum
Swindon has long rows of Victorian and Edwardian terraces, and the railway streets near the old works are a clear example. The Council's appraisal of the Railway Conservation Area says the roofs there are generally slate. A long terrace slope is a good job for slate, but it brings its own cost drivers.
How much does access add on a terrace?
Scaffolding is the biggest single extra. MyBuilder's scaffolding guide gives around £850 to £1,200 to scaffold a two-storey house in the usual way, and a tall or awkwardly placed terrace can sit above that. Where the back of a house is reached through a narrow passage or over a lean-to, extra hand-carrying of slate adds labour time too.
Why do chimneys and party walls matter?
A terrace slope runs into a party wall at each side, and many have one or two shared stacks. Every junction needs lead: stepped flashings against the wall, soakers under the slates, and aprons and back gutters at the chimney. A short plain slope costs much less per square metre than a slope with a stack, a valley and a dormer cheek, because the slate itself is the quick part of the job.
Roof area matters, but so does the number of details. A plain gable and a house with a rear return and a valley may have the same footprint and still price very differently.
Why Welsh costs more than Spanish
Welsh slate sits at the top of the published range, and the main reason is its track record.It has a long reputation, and the published ranges put its service life at the top of the natural slates. MyBuilder describes Welsh slate as regularly lasting over a century, and Spanish slate at 75 to 100 years.
That gap in life is one reason people pay the premium. Over the long run, a roof that does not need reslating in the owner's lifetime can work out cheaper per year than a cheaper slate that does. It is also a reason some owners choose Spanish: a well-fixed Spanish slate roof still gives several generations of cover, and the saving per square metre is real on a large roof.
The difference between the two shows most clearly on a big roof. Over 70 m², a gap of £40 to £50 per m² between the published ranges adds up to a noticeable sum, so ask the survey to price both if you are undecided.
Looks count for something as well. The two slates differ in colour and texture once they have weathered, and a terrace that already carries one of them looks odd with the other on a single house. If neighbours on a conservation-area terrace have one or the other, matching can decide the choice before cost does. Our page on matching roof slates goes into that.
Reclaimed and fibre-cement as alternatives
Reclaimed slate looks like a way to save money and sometimes is. MyBuilder's range of £110 to £150 per m² sits between Spanish and Welsh. The saving is smaller than people expect because reclaimed slates have to be sorted, holed again where needed and laid with extra care, and the supply of a matching batch can run short. The look, though, is hard to copy. If your house already has weathered slates on the front, a reclaimed batch can blend where new ones stand out for years. Our guide to reclaimed slate explains how we judge a batch.
Fibre-cement slate is the lower-cost route in the market, and MyBuilder quotes a life of 30 to 50 years for synthetic slate. It is lighter and more uniform, and it needs different fixings. Our comparison of natural and fibre-cement slate covers where it fits and where it does not. A figure per m² depends on the product chosen, so we give it only after seeing your roof.
One more thing to know: the lowest-priced slate to buy is not always the lowest-priced slate to fit. A slate that needs more care to cut and dress costs more in labour, whatever the material price.
What the whole job includes beyond the slate
A per-square-metre figure is a shorthand. A slate re-roof usually involves several pieces of work that the figure only partly covers, and any of them can change a total.
- Stripping and disposal. Old slates, battens and underlay are removed and the waste taken away. MyBuilder's new roof guide quotes disposal at £100 to £1,000 depending on volume.
- Timber repairs. Rotten battens are replaced as standard on a re-roof. Rafters, wall plates and sarking boards beneath the slates are only known once the roof is open.
- Underlay. Many Victorian roofs have none, and a modern breathable membrane is normally laid under the new slate.
- Lead and flashings. Checkatrade gives stepped lead flashing at £80 to £120 per metre and straight flashing at £50 to £70 per metre, excluding VAT.
- Ridge and hip details. MyBuilder lists £300 to £600 for ridge tiles that are re-bedded or replaced.
This is why a number from a guide only takes you so far. The survey photographs show the underlay, the battens, the lead and the ridge, and the price we write down reflects what that particular roof needs.
Pitch, headlap and how much slate you buy
Price per square metre hides a quantity question. Every slate sits partly under the courses above, and the depth of that cover is the headlap. It is measured from the bottom edge of the slate two courses up. A lower pitch needs more headlap to keep rain out, and more headlap means more slate for every square metre of roof.
Cupa Pizarras, a slate manufacturer, publishes headlap tables based on BS 5534. For a 500 mm by 300 mm slate in moderate exposure, the table asks for 115 mm of headlap at a 20 degree pitch, 95 mm at 25 degrees and 55 mm at 45 degrees. Below 20 degrees the table stops. A shallow slope eats a good deal more material than a steep one.
Do shallow roofs really cost more to slate?
They can. A lean-to or a low-pitched rear extension carrying natural slate needs the larger headlap, which raises the slate count and the weight. The same size of slate on a steep Victorian main roof uses far less cover per square metre. Slate size also feeds in: Cupa gives no headlap values below 25 degrees for a 600 mm by 300 mm slate, so some sizes are simply unavailable on a gentle slope.
Does the fixing method change the price?
Yes, a little. Cupa advises against hook fixings on a slope lower than 25 degrees, which leaves nails for a low roof. Nailing is slower than hanging with hooks, and that shows up in labour. Our guide on slate sizes and headlaps explains the numbers, and the survey records your pitch so the figures are for your roof, not an average one.
Repair costs, and when they stop making sense
Sometimes the right answer is not a re-roof at all. MyBuilder puts minor roof repairs at £100 to £300 and moderate repairs at £500 to £1,000. Checkatrade's repair guide (table dated June 2026) gives Spanish natural slate repairs at £150 to £220 per m², excluding VAT and access equipment. Set that beside the re-roof range and the pattern is plain: repair work costs more per square metre, because it is small and fiddly, yet it touches far less roof.
The point where repair stops making sense is usually clear from the survey. A few slipped slates held by sound nails are a repair. A whole slope where the nails are failing, a technical fault known as nail sickness, will keep producing slipped slates and the repair bills will add up. Our guide on how long a slate roof lasts shows what ageing looks like on a roof, so you can judge for yourself from the photographs we send.
If a repair really does cure the fault, the written quote says repair, and the fuller job stays a decision for another year. Details of the repair side are on our slate roofing page.
Building Regulations, weight and thermal upgrades
Cost can change if the job crosses a regulatory line. The Planning Portal sets the test: an application is not normally required while less than 25 per cent of the total building envelope and less than 50 per cent of the roof are affected. Exceed those limits and approval applies, with possible further work such as better insulation.
Part L is the usual trigger for that insulation work. Once renovation passes 50 per cent of the roof surface, the entire roof is brought up to the stated U-value, not just the part you touched. That adds cost, but it also cuts heating loss, and it is worth asking about before the scaffold goes up.
Covering weight matters too. The Planning Portal lists a heavier covering, 15 per cent or more on the existing weight, among the changes that need approval. Swapping a lighter covering for natural slate is the sort of change that can get close, and the roof structure may then need checking. Where the work is notifiable, we go through the consent position with you and see the notification through.
Read more on the weight side in our guide to slate weight.