Anyone planning stone roof work soon meets the same question. Should replacement slates be reclaimed, lifted from a demolished barn or bought from a dealer's yard, or should they be new? It sounds like a matter of budget and taste. For a historic building it is also a matter of policy.
Cotswold District Council published technical guidance on stone slate roofing in April 2000, and it reprints an English Heritage policy on exactly this point. Historic England's own current advice note would not open when we tried it, so this guide leans on the council's reprint and treats it as established policy from 2000, not the latest word. We take the policy one rule at a time, then look at how it shapes a repair, a re-lay and a purchase. The wider service is on our Cotswold stone roofing page.
The policy in four rules
The reprinted policy boils down to four short rules.
- Choose newly cut stone slates over second-hand ones whenever you have the option.
- Put reclaimed slates back only where they were taken from: the same building, or the same group of buildings.
- Choose new slates that echo the old ones on five counts: stone type, colour, surface texture, length and width, and thickness.
- Keep look-alike products off old buildings altogether: resin-fibre slates, concrete tiles and cast imitations of stone.
Two sharper points follow. Never put sandstone where limestone was, or the reverse. And a slate that has been sawn, as opposed to split along its bed, can be unacceptable on technical grounds and on looks.
What the policy is, and is not
It is good-practice advice written by a district council for owners and occupiers. It is not a statute, and it does not say what an owner is free to do with a house that is unlisted and outside any conservation area. Yet when a planning officer or conservation officer is asked for a view, this is the position they will recognise, so it pays to build a job around it.
Why old slates stay with their own roof
The rule that surprises people is the second one. The council's guidance explains it: the appetite for second-hand stone has seen other old buildings stripped of their roofs, in some cases by theft. Each reclaimed slate sold to one roof was lifted from another.
The conservation logic
An old roof is part of the building's record. Its slates carry the character of their quarry, decades of weathering and the marks of earlier repairs. Shipping them across the county blurs that record and invites the next barn to be stripped. Keeping each roof's stone on its own roof protects the building and its neighbours alike.
What it means on a job
When we take your roof apart, the sound slates are sorted and returned to the same house. That is the simplest way to follow the policy. The question of new against reclaimed only arises for the slates that fail the sort, and for those the policy says new stone, matched. Our guide to re-laying a Cotswold stone roof follows the whole job.
Matching new stone to old, one quality at a time
The policy names five qualities a new slate should share with the old. Each one guards against a different way a stone roof can go wrong.
Geological type
Two oolitic limestones supply Cotswold stone slates, according to Cotswold District Council: Forest Marble, which is worked by hand, and Stonesfield Slate, which opens in the frost. A stone of the wrong type can weather differently, hold water differently and age to another colour. The policy is firm that sandstone and limestone are never swapped.
Colour and texture
A new slate often looks pale beside weathered neighbours. That softens over seasons, but a slate cut from the wrong stone never will. Texture is easier to judge in the hand than from a photograph, which is why we like to lay samples against the old stone, in daylight, before any order goes in.
Size and thickness
Courses shorten as they climb, so each replacement needs a length that suits the band it joins. Thickness affects lay too. A slate that is too thick lifts the courses above it, and one that is too thin may crack under load. Our guide to stone slate repairs shows how this works for a single replacement.
Where substitutes fit, and where they do not
For old buildings the policy turns down manufactured stand-ins for split stone, however closely they are moulded. The reasons are practical as well as visual.
Weight and lay
Stone is very heavy: 1,000 kg per 10 m² is the 2000 guidance's figure for a stone slate roof. Fitting something far lighter changes what the rafters carry. The Planning Portal sets approval at a covering 15 per cent heavier or more, and Approved Document A treats a significant change in loading as something to have checked. Going lighter is not covered by that rule, but the timbers were sized for stone and deserve the same thought.
Appearance
Moulded products repeat a pattern and cannot grade the way split stone does. Viewed from the lane they tend to look uniform, and the difference stands out on a small roof beside the road.
A quote for a historic stone roof that offers reconstituted slates is pricing a different roof. Ask for stone, by type, and compare quotes on that basis.
We price like for like: an old stone roof is covered in stone again.
Imported limestone, and a word on scarcity
Some Cotswold projects have used slate-like limestone brought in from France's Côte d'Or, and the 2000 guidance calls the results very good. It does not treat that as a loophole. It reflects a real difficulty with supply: the guidance counted only five Cotswold quarries in production, a figure now a quarter of a century old, so it tells us nothing reliable about today.
What a seller says
One supplier says its stone is quarried in India, not in the Cotswolds, and calls both new and reclaimed Cotswold stone scarce and dear. That comes from an interested party, so it is a pointer, not evidence. What it does show is that the market is wide, and that where a slate comes from is a fair question to put to anyone quoting.
Matching is the test
Origin counts for less than whether the slate passes the five tests listed earlier. A limestone slate from abroad that matches an old limestone roof can be a better choice than a poor local one, and a mismatched local slate is still a mismatch. Where new slates actually come from is covered by our answer on new stone slate sources.
When the policy meets planning and consent
A like-for-like re-roof normally does not count as development under the Town and Country Planning Act, because the outward appearance of the building is not materially changed. That is a sound general principle with edges. If your house is listed, the Planning (Listed Buildings and Conservation Areas) Act creates an offence for altering it without authorisation where its special character suffers.
Listed buildings
On listed buildings, Stroud District Council is clear that every grade is protected in law, inside and out. Swapping one stone for another, or stone for a substitute, is the kind of change its conservation team should see first. A repair done like for like can still warrant a phone call. We leave legal advice to others, so ask Stroud District Council's planning team before work starts; we can send roof photographs to support your enquiry.
Conservation areas
Stroud District has 41 conservation areas, with Article 4 Directions in five. Whether those directions reach roof coverings is unstated on the council's page, so ask the planning team. A stone roof in a conservation area is also the one the neighbours see most, which gives the matching rules extra weight there. Raise consents with us before any scaffold goes up.
Questions worth putting to a slate dealer
Policy is easy to state and hard to check at the yard gate. A dealer who knows the trade will answer the following without fuss, and a vague reply tells you something too.
- Which stone is it, and which quarry or which building did it come from?
- Was it split along the bed or cut with a saw?
- Is it graded by length, and how many slates sit in each band?
- Is the thickness even enough for a course to lie flat on its battens?
- Can you see a sample, in daylight, beside your own slates?
Why provenance matters on paper
If the house is listed, the conservation officer may ask what the new slates are and where they came from. A receipt that names the stone and the source answers that in a line. A vague invoice leaves you to argue the point after the roof is on.
Reclaimed stock that is offered to you
You will sometimes be offered reclaimed slates cheaply, with a story attached. The policy view, and our own, is that stone lifted from somebody else's roof is not a bargain. Where the origin cannot be shown, we would rather order new stone matched to yours and keep the paperwork clean.
How the policy shapes our work on your roof
On a stone roof the order of work follows the policy. We survey and photograph the roof, record the course lengths and note the stone type from what shows. When the slates come off, each is checked and sorted, and the sound ones go back into their own courses on your house.
Where new stone comes in
Slates that fail the sort are listed by length, and the new stone is ordered to suit: same type, close in colour and texture, and cut to the right sizes. We show you samples where we can. On a listed building, the sample is also what you may need to show the conservation officer.
What goes into the quote
New stone is part of the written quote; that shows what the policy adds and what your own salvage takes off. Checkatrade (2026) puts stone slate roofing nationally at about £160 to £210 per m² and does not single out the Cotswolds. Our answer on new stone sources deals with the supply side.
A written 10-year workmanship guarantee comes with the job. On completion we sweep the site and take away the rubbish.