Natural Cotslay Roof Stone
Natural stone for Cotswold roofs, in Aged and Buff, laid in random diminishing courses
Cotslay Natural Roof Stone is ethically sourced natural stone for Cotswold roofs, supplied in Aged and Buff. It is real natural stone, calibrated to lie flat and pre-drilled, laid in random diminishing courses in the traditional Cotswold way.
What Is Cotswold Roof Stone?
A Cotswold stone slate roof has a look that is hard to imitate: coursed stone stepping down in size from eaves to ridge, in soft honey, buff and grey-brown tones that settle further into the landscape every year. Cotslay Natural Roof Stone is our answer to that roofscape — ethically sourced natural stone, selected and finished to match Cotswold roofs, laid in random diminishing courses in the traditional Cotswold way.
A Cotswold roof goes by several names — Cotswold stone roof slates, Cotswold stone roof tiles, Cotswold slates — and they all describe the same kind of roof: thick, riven-faced stone laid in diminishing courses rather than a single repeating size. Cotslay is supplied to build that roof. Stone roofing is a discipline of its own. The stones are heavier, they are hung on pegs or nailed through a pre-formed hole, and they are set out to a schedule that tells the roofer which size belongs in which course.
New and reclaimed Cotswold stone has become scarce and expensive. Cotslay gives architects, conservation officers and roofing contractors real stone that behaves like the original: it weathers into the roofscape rather than sitting on top of it, and it is suitable for use in Conservation Areas, National Parks and on Grade 1 and Grade 2 Listed Buildings.*
*Approval is property-specific and must be obtained from your local planning authority for every project.
Cotslay and Cotswold Stone — the Difference
Cotslay is ethically sourced natural stone, quarried in India and selected to match the colour, texture and coursing of a Cotswold roof. It is not quarried in the Cotswolds — new and reclaimed Cotswold stone is now in very short supply, which is why Cotslay exists. It is an alternative to Cotswold stone, not a substitute for it on a listed building — see below on Conservation Areas and listing.
What Cotswold Stone Roofing Is Called
The same roof goes by several names. Cotswold stone slates, Cotswold roof slates and Cotswold slates all describe stone split thin and hung in diminishing courses. Older sources call it tile-stone, because the material is oolitic limestone rather than true slate — it is a stone tile that behaves like a slate. Merchants and architects also say Cotswold stone tiles or Cotswold roof tiles. Whichever term you have been quoted under, a Cotswold stone slate roof is what we supply the stone for — read our Cotswold stone slate roofing guide for the full background.
What Is a Random Diminishing Course Roof?
The largest stones sit at the eaves and every course above steps down, so the roof reads as a series of narrowing bands right up to the ridge, giving a Cotswold stone slate roof a depth that a single-size covering cannot reproduce.
"Random" refers to the widths. Within each course the heights are fixed but the widths vary, so the vertical joints never line up and the roof avoids the gridded look of a modern single-size covering. Diminishing courses are also why a stone roof reads correctly from the ground: the eye follows the narrowing bands and the pitch appears taller and better proportioned than it actually is.
Cotslay is supplied across 41 sizes — main sizes from 24" x 20" down to 10" x 4", plus top sizes and under-eaves courses — so a roof can be set out in random diminishing courses without cutting to fit. That matters on a conservation project, where a cut edge on a piece of roof stone is visible and a conservation officer will notice it.
What Colours and Ancillaries Are Available?
Two colourways, both at the same rate, plus the ridge and ventilation pieces needed to finish the roof without importing a different product at the top course.
Aged
The darker colourway. Weathered grey-brown, for matching into existing stone.
Buff
The lighter colourway. Warm honey and cream, for new build and full re-roofs.
Reproduction Stone Ridge
Supplied to match Cotslay roof stone, finishing the roof at the apex.
Vent Slate
In-line ventilation that sits within the coursing.
What Sizes Do Cotswold Stone Roof Tiles Come In?
Cotswold Stone Slate Sizes
Heights are measured to the peg hole. Your batten schedule tells you which size goes in which course.
| Main Slates | 4" | 6" | 8" | 10" | 12" | 14" | 20" |
|---|---|---|---|---|---|---|---|
| 10" | 10" x 4" available | 10" x 6" available | 10" x 8" available | 10" x 10" not available | 10" x 12" available | 10" x 14" not available | 10" x 20" not available |
| 12" | 12" x 4" available | 12" x 6" available | 12" x 8" available | 12" x 10" not available | 12" x 12" available | 12" x 14" not available | 12" x 20" not available |
| 14" | 14" x 4" available | 14" x 6" not available | 14" x 8" available | 14" x 10" available | 14" x 12" not available | 14" x 14" available | 14" x 20" available |
| 16" | 16" x 4" available | 16" x 6" not available | 16" x 8" available | 16" x 10" available | 16" x 12" not available | 16" x 14" available | 16" x 20" available |
| 18" | 18" x 4" not available | 18" x 6" available | 18" x 8" available | 18" x 10" available | 18" x 12" not available | 18" x 14" available | 18" x 20" available |
| 20" | 20" x 4" not available | 20" x 6" not available | 20" x 8" available | 20" x 10" available | 20" x 12" not available | 20" x 14" available | 20" x 20" available |
| 22" | 22" x 4" not available | 22" x 6" not available | 22" x 8" available | 22" x 10" not available | 22" x 12" available | 22" x 14" available | 22" x 20" available |
| 24" | 24" x 4" not available | 24" x 6" not available | 24" x 8" available | 24" x 10" not available | 24" x 12" available | 24" x 14" available | 24" x 20" available |
- Top slates: 7" high x 4", 6", 8", 10" wide
- Under eaves: 12" x 18" and 17" x 20"
Why Specify Cotslay Natural Roof Stone?
Extensive stock
A diminishing roof only works if every size in the schedule arrives together, so availability across the full size range matters more here than on any other roof. Talk to the team with your roof measurements before you commit to a programme and we will confirm what we can supply and when.
Fully calibrated
Every stone is calibrated to a consistent thickness so it lies flat on the batten. That removes the sorting and dressing time reclaimed stone demands, and it means the roof goes on at a predictable rate.
Reduced wastage
We calculate the requirement from your roof and issue a full batten schedule against it, so the quantity you order is close to the quantity that goes on the roof.
Batten layout service
Send us your roof measurements and we return a batten schedule and laying pattern for the whole roof.
Can You Use It in a Conservation Area or on a Listed Building?
Cotslay is suitable for consideration in Conservation Areas, National Parks and on Grade 1 and 2 Listed Buildings. Approval is never granted to a product — it is granted to a property, by the local planning authority, and it must be obtained for every project.
In a Conservation Area, where the building itself is not listed, natural stone laid in random diminishing courses will usually satisfy what the authority is looking for.
On a listed building the bar is higher. Conservation officers may require new stone to match the existing in geological type, colour, texture, size and thickness, and may specify split rather than sawn stone. Speak to your conservation officer before specifying anything, and send them a sample and the batten schedule early.
For repairs and extensions on an existing stone roof, the Aged colourway is normally the closer match; Buff suits new build and full re-roofs where the whole elevation will weather together.
*Approval is property-specific and must be obtained from your local planning authority for every project.
About Cotslay - standards, guarantee and sizes
| Material | Ethically sourced natural roof stone |
|---|---|
| Colours | Aged, Buff |
| Price | £180 per m² excluding VAT, Aged and Buff |
| Weight (laid) | 120-140 kg/m2 |
| Fixing | Pre-drilled 8mm peg hole |
| Coursing | Random diminishing courses; batten schedule supplied |
| Sizes | 35 main + 4 top slates + 2 under eaves |
| Approvals | Conservation Areas, National Parks, Grade 1 and 2 Listed Buildings* |
| Ancillaries | Reproduction Stone Ridge, Vent Slate |
| Origin | Quarried in India, ethically sourced |
*Approval is property-specific and must be obtained from your local planning authority for every project.
How Much Do Cotswold Stone Roof Slates Cost?
£180 per m² excluding VAT
Aged and Buff, the same rate either way
Cotslay is £180 per square metre excluding VAT, and the price is the same in both Aged and Buff. Delivery is quoted separately according to the size of the order. Send us your roof measurements and we will price the actual roof rather than a rate per square metre. Reclaimed and newly quarried Cotswold stone are priced by whatever happens to be available, and the sizes you get are whatever comes out of the batch. With Cotslay you know the price, the sizes and the delivery before you commit.
Get a Quote for Your RoofWill Your Roof Take the Weight?
A laid Cotslay stone slate roof weighs 120-140 kg/m². Where laid weight is a limitation, we also supply reproduction diminishing stone in Natural Weathered, Country Weathered and Turned York.
Where Do You Deliver Cotswold Stone Roofing?
We supply nationwide from our Cheshire base, and deliver regularly across the Cotswolds. Gloucestershire takes the largest share of our stone, with regular loads into the villages north and south of Cirencester. Oxfordshire deliveries run into the western edge of the county, where stone slate roofs are the norm rather than the exception. Wiltshire projects are usually conservation repairs on existing stone roofs, and Worcestershire orders tend to be full re-roofs on the northern fringe of the region. Warwickshire is served on the same weekly routes, and Somerset is covered for both new build and reinstatement work on older stone slate roofs. Deliveries are palletised by size so the courses can be set out in schedule order on site rather than sorted from a single heap.
Our own teams are also available for full supply and fit where you would rather one contract covered both the material and the labour, including stripping and setting out an existing stone roof for reinstatement.
Cotswold roof stone questions
Cotslay Roofs We Have Supplied
Cotslay laid in random diminishing courses on Cotswold-style roofs.
Request a Sample Today
See the colour, the texture and the thickness in your own light before you specify. Free samples, nationwide delivery.