Where do new Cotswold stone slates come from?

For a Cotswold building, the first choice is new slate cut at a Cotswold quarry, because the rock then matches the geology of the original. The council's technical note of April 2000 names two sources of Cotswold slate, Forest Marble and Stonesfield Slate, and the English Heritage policy it reprints wants any replacement to sit close to the old stone in rock type, colour, grain, length and thickness.

When that guide was written, the council counted five Cotswold quarries producing. That is a 2000 figure and we do not present it as current. Which quarries are working today, and how much they can supply, shifts with demand and consents, so we would rather confirm availability when quoting than repeat a number from a leaflet that is twenty-six years old. Because limestone splits into far more short pieces than long ones, the long slates needed for the eaves are worth a direct question about supply and lead time before a date is fixed.

That document goes on to say that limestone slate shipped in from the Côte d'Or in France has worked out very well on certain schemes in the district. It is a limestone, as the Cotswold stones are, so it belongs to the same family, and it can be split to comparable thicknesses. It is not identical, and the matching rules still apply, so on a protected building the planning team may want to see samples before agreeing. We would not propose it for a listed roof without checking first.

For an ordinary home, French limestone is one of the options that makes a re-lay practical when local supply is thin. The decision then turns on price, delivery times, colour, surface texture and how well the new stone will weather beside the older slates on neighbouring roofs. One sample slate propped against your own slope will tell you more than a page of brochure photographs.

Some stone sold for Cotswold roofs travels much further. One supplier, Cotslay, says on its website that its slate is quarried in India and not in the Cotswolds, and adds that both new and second-hand Cotswold stone are now hard to find and dear. That is a seller describing its own market, so we report it as a claim, not as an independent finding.

It does suggest the right questions for any supplier. Which rock is it? Where was it quarried? Is it split or sawn? The English Heritage policy warns that sawing in place of splitting can be unacceptable on historic buildings, both technically and visually, and that sandstone and limestone should not be exchanged. A cheaper imported sandstone laid on a limestone roof is exactly the swap it warns against. Our answer on stone slate or stone tile is a useful start on the vocabulary.

Second-hand slates form a separate market with a separate policy. The council's guide prefers new slates wherever possible, wants reclaimed ones kept for the building or group they came from, and ties the market for old stone to roofs being taken off other buildings, now and then by theft. Our guide to reclaimed or new stone slates sets out that policy in full.

On a re-lay we sort your own stone first, because it already matches. When a slope is stripped, the guidance observes that around half of the old slates are often too far gone to reuse, so new stone makes up the balance. The sorting decides how much has to be bought, and it is a large part of why a quote after the survey is more dependable than a rough figure given over the phone.

Matching new to old

Ask for a delivery of the new slates to be laid out on the ground beside the old so you can judge them in daylight. Colour changes noticeably between a wet slate and a dry one, so look at both.

Fresh stone is paler and sharper than a slope weathered for generations. It darkens and takes on lichen over the years, and many owners place the new slates on a less visible slope or scatter them among the old ones so the roof ages evenly.

The 2026 edition of Checkatrade's slate cost guide puts stone slate at about £160 to £210 per m², and adds that the rate swings with the quarry, with new against second-hand, and with the region. Treat it as a loose national marker; nothing in it is specific to the Cotswolds. The source of the stone is among the biggest drivers of the total, which is why we ask for it in writing.

Before accepting a quote, ask for the rock type, the quarry or country of origin, whether the stone is split or sawn, the lengths by course and a sample. The planning side is covered in our answer on consent for a stone re-roof, and the cover side in insuring a stone roof, since a loss can mean sourcing stone in a hurry. Our quote follows a survey with photographs, and lists the stone, scaffold, labour and waste separately. A written ten-year guarantee covers our workmanship. See also our Cotswold stone roofing page.