Reclaimed or newly quarried Horsham stone?

Reclaimed stone means slabs that have already served on another roof. They come from a barn that was pulled down, an outbuilding that was re-covered in something lighter, or a neighbouring job where the owner chose not to reuse everything. Salvage yards and stone merchants sort them and sell them on.

The great strength of reclaimed stone is that it already looks right. A century or more of weather has softened the edges and darkened the surface, and lichen has settled in. A reclaimed slab set beside a weathered neighbour tends to vanish into the course, which is what you want from a repair. Using salvaged material also avoids cutting fresh rock for a repair that needs only a handful of slabs.

The weakness is that the history is unknown. A salvaged slab may have been cracked, may have taken frost, or may be laminating, which means splitting into layers along its bedding. It may carry old fixing holes in the wrong places for your battens. Sizes are mixed, so the pile has to be sorted into the sizes your courses need, and the right size at the right thickness can be hard to find.

Own stone first

The best reclaimed stone is often on the same roof. Slabs lifted from one slope, an outbuilding or a rear pitch can be redistributed so the least weathered ones go where they are seen least. A conservation officer will generally want to know the roof's own stone is being reused as far as it will go before anything is brought in. Our guide on repairing, re-laying or replacing a Horsham stone roof explains how the survey decides that.

Newly quarried stone is split from the rock for the job. Because it is produced to order, it can be had in the sizes the courses call for, which makes the grading easier. There is no doubt about the history of a fresh slab. It has not been through a winter on someone else's roof, and it should be free of old fixing holes, so it can be pegged or nailed wherever your battens fall.

The cost of that tidiness is the look. Fresh stone is cleaner and usually lighter in tone than a roof that has weathered for generations, and a block of new slabs among old ones can stand out from the lane for years. Weathering narrows the gap, but slowly. Where the new slabs are few, scattering them across a slope instead of grouping them in one patch helps them settle in. Where a whole slope is being re-laid and new stone fills a large share, the finished roof will read as newer than its neighbours until it ages.

Lead times deserve a place in the plan. If a roof needs a large number of slabs in particular sizes, the order cannot be rushed, and the roof may need a temporary cover in the meantime. A realistic timetable is agreed once the survey shows how much stone is needed. Supply is the other question. Stone in the right sizes, thickness and colour is not always on the shelf, and waiting times can be long. That is another reason to start the conversation early. Our answer on where Horsham stone comes from today deals with the sourcing side.

Ask any supplier to show you the stone, not just describe it. A photograph of the actual pallet, or a sample slab you can hold, tells you far more than a name on a quote. Lay a few out in daylight beside slabs from your own roof before you agree to anything, and check the faces for flaking before they go anywhere near a scaffold.

Matching is a judgement, and a good survey makes it concrete. Four things decide whether a replacement slab suits the course it goes into.

Thickness comes first. A thin slab among thick ones sits badly, lifts at the tail and leaves a gap for wind and rain. Size is second. Courses diminish from the eaves to the ridge, so a replacement needs to be the right size for its row, and a slab that is too big or too small throws out the rows around it. Colour and texture are third. Local stone ranges widely in tone, from warm ochre to cool grey, and a mismatch shows from the road. Fourth is condition: a replacement should not be flaking, laminating or cracked before it is laid.

Weight on the roof matters here too. Stone is heavy, and the timbers beneath it were built to carry it. Putting a full slope of new stone in place of thinner or missing pieces shifts the load. The Planning Portal puts the trigger for a building control application at a new covering that is 15 per cent or more heavier than the one it replaces. Replacing like with like in the same stone rarely moves that figure far, but the question is worth raising at the survey, and our guide on how much a Horsham stone roof weighs looks at the structure.

No supplier's description replaces your own eye. Many roofs end up with a blend. Reclaimed slabs take the visible faces, new ones fill the sizes that cannot be found, and the oldest, most weathered pieces go together on the front slope so they read as one. We lay the mix out on the ground first, so you see the effect before it goes up. The surveyor, the roofer and the owner should all agree on the match before the first slab goes up, and where the building is protected, the conservation officer should agree too.

On a listed building or in a conservation area, the choice is not only yours. The conservation officer advises the council on whether the work respects the building's character, and the stone is a large part of it.

A few patterns come up often. Officers tend to favour reuse of the building's own stone, then reclaimed stone from a source that can be named, and new quarried stone as the last resort for any shortfall. Whatever you propose, expect to be asked where the replacement stone comes from, how it will be matched, and where on the roof it will go. Write the answers down before you apply.

There is also a point about where reclaimed stone has been. Buying slabs that were stripped from another old building raises its own concern if that building was protected and the stripping went ahead without consent. Ask the merchant plainly about the source, and avoid stone that cannot be traced. Reputable dealers can say roughly where a batch came from, how it has been stored since and whether it sat on bare ground, where damp and frost work into the layers. A dealer who is happy to name the job the slabs came from is a good sign.

Our guide on Horsham stone roofs on listed buildings covers the application itself. The National Park Authority takes the view that everyday maintenance and minor in-place repairs need no listed building consent. Replacing a handful of slabs in matching stone may fit that, while stripping a slope and bringing in a lot of different stone may not, so describe the plan in full and let the council say.

Where the house is neither listed nor in a protected area, the choice is yours, but the same matching rules give the best result.

We never settle the stone before the survey. The order is simple: look at the roof, photograph it, count what can be reused, then talk about where any shortfall comes from.

In the loft we check the battens and rafter ends, because rotten timber changes the amount of work. On the slopes we mark each slab that has slipped, cracked or flaked, and photograph the lines of failure. The survey then gives us three numbers: how much stone is sound, how much is lost, and how much of the loss is on the street side, where a mismatch shows most.

From that we say whether reclaimed, new or a mix suits the roof. A small shortfall on a rear slope often goes best with reclaimed stone placed where it is seen least. A larger gap, or a need for one particular size, may point to fresh stone. A listed roof will bring the conservation officer into the decision, so we write it up in terms you can pass on.

The price follows as one written total, because the amount of sound stone, the state of the timbers, the access and the finish at ridges and valleys all move it and none can be judged from the garden. You see the photographs behind our verdict before any figure arrives.

If you are weighing the same question against a different covering altogether, our guide on Horsham stone against other roofing materials compares them. To start, send photographs of each slope by WhatsApp or ring 01243 252373, and tell us whether the building is listed.