Checking the provenance of reclaimed stone slates

1Why the source matters

Stone slates do not come from a catalogue. Many offered as reclaimed have been lifted from another roof, and the question is whose roof, and with what permission. A barn properly taken down and sold is one thing. A church or farmhouse stripped overnight is another.

The Association is blunt about the harm: a trade in slates lifted from other buildings encourages the stripping of historic roofs, which is why it asks owners to avoid it. If demand for salvaged stone did not exist, there would be less reason to strip a standing roof, and fewer thefts from buildings that cannot easily be watched.

There is a practical risk too. If slates were stolen, you may be buying goods that were never the seller's to sell, while a building owner somewhere is coping with a roof open to the weather. Horsham stone roofing sets out the wider background to why salvaged stone turns up so often.

2Your own roof is the cleanest source

The safest history belongs to the stone already on your house. The Association names reuse of what is already on the roof as the first choice, and that is what a careful relay does: lift, sort, repair the timbers beneath and lay the same stone back.

Its guidance goes on to say that suitable new Horsham slates should be used for any gap before reaching for stone from elsewhere. Salvaged slates come after that, and only when the alternatives have run out. We follow the same order on every roof.

None of this means salvaged stone is never right. It turns up often because new supply is short, and a 2019 report said owners commonly use reclaimed slates, which can mean stone taken from other historic structures. Common is not the same as recommended, and that very report is why the source needs checking. The stone roofs in the South Downs National Park page shows where records may be asked for.

3Questions to put to a seller

Ask where the slates came from, in terms you could write down: which building, which parish, when it came down and why. A genuine dealer usually knows. Vague answers, a pile with no history or an urgent cash price are warning signs.

Ask whether the building was demolished or converted, and whether any consent applied. Unauthorised works to a listed building are an offence under the 1990 Act, so a seller who cannot say may be passing on a risk that follows the stone.

Ask for the source in writing alongside the invoice, and file both with the deeds or the roof records. A dealer who is happy to put a name and a date on paper is usually a dealer with nothing to hide, and one who hesitates has told you something useful. Ask what type of stone it is, too: the Association advises against pairing limestone slates with sandstones, so you also need to know the material suits your roof. Answers you cannot get are an answer in themselves.

4What we do on a stone roof

We start with your own slates and photograph what is there. We sort them by length and tell you plainly how many can be reused and what shortfall remains. That figure drives everything that follows.

For the gap, we look first for new Horsham slates. If none can be found, we talk through salvaged stone and the questions above before anything is ordered. We pass on stone with an unclear history, even when the price looks tempting, because a roof laid with doubtful stone is a problem you inherit and we would rather you did not.

On a large job the sorting can take a day or more before a single slab goes up, and that time is well spent. A tidy count of lengths in each pile tells you whether the shortfall is a handful of slabs or a whole slope, which in turn decides whether buying anything in is worth the trouble at all.

Your written quote after the survey gives a single total and says where the stone is expected to come from. How slabs must match in length is covered in stone slate sizes, and the finish beneath them in torching under stone slates, so you can see what a replacement has to satisfy before it is bought.

5Protecting yourself afterwards

Keep every receipt, along with the written source for any slates that went on. A listed house or one in a protected area may prompt the council to ask where the replacement stone originated, and a buyer's conveyancer is likely to raise it at sale. A tidy folder answers both in a minute, where a gap can cost weeks.

Tell your insurer which materials make up the roof and whether any of it is salvaged. Stone slate roof cost explains why work on stone is large and closely read.

If you suspect slates already on your roof, or offered to you, are stolen, do not carry on regardless. Stop, write down what you know and speak to the police. A sound source protects your roof and somebody else's, and it keeps your own paperwork straightforward when the house is sold.