Chapter one
Horsham stone and Carstone around Church Street
A band of sandstone under the Downs gave Storrington its walls, and Horsham slabs still cover some of its oldest roofs.
Storrington lies on an 800 m wide band of Folkestone Formation sandstone below the Downs. Horsham District Council's appraisal says that band is the source of Carstone, a brown sandy ironstone used on several buildings in the conservation area, and it lists the local materials as Carstone, some imported stone, Sussex brick and flint, some Horsham slab stone slates and many types of local clay tile. The same document picks out Horsham stone slab roofs such as those in Church Street. A roofer here meets stone, brick and flint walls under tile and stone coverings on the same street, and each needs its own handling. Weight matters on a stone roof too. That council's separate appraisal of Horsham describes its stone slate roofs as steeply pitched and carried by sturdy timbers able to bear their weight, which is why the rafters and wall plates get as much of our attention as the slabs.
At a glance
- Storrington lies on an 800 m band of sandstone
- Horsham slab roofs are recorded in Church Street
- The roof's original slabs are kept in use first
1.1 How a Horsham slab roof is read
The Stone Roofing Association's guide calls the Horsham material a calcareous, flaggy sandstone, split into random sizes and graded so that the biggest sit low and the smallest high. Because no two slabs match, such a roof cannot be re-covered from a pallet. It is mended by lifting slabs, sorting them by size and setting them back in order on sound battens. The Association's first preference is plain: keep whatever original slabs the roof still has. Slabs salvaged from elsewhere are widely used in practice, since supply was reported to be in crisis in 2019, but the Association says to avoid them whenever possible, and where that is impossible, buyers should check the slabs were legitimately obtained. Suitable new Horsham slates, where they exist, should cover any shortfall.
1.2 Where stone meets wall
Carstone, flint and brick each take a flashing differently. A flashing is lead folded into a strip, and it bridges the join between a roof and a wall or chimney. Flint offers an uneven face to bed it into, and Carstone's rough courses do much the same, so the slot is cut to follow the wall's own pattern, not forced into a straight line. When lead lifts, the water finds its way into the masonry and appears as a damp patch elsewhere, so the source is traced before a quote is written. Our Horsham stone roofing page covers lifting and relaying slabs, and our lead roofing page covers the metalwork.
Horsham slab roofs in brief
- Stone
- Calcareous, flaggy sandstone
- Laying
- Graded sizes, biggest low on the roof, smallest at the top
- First choice
- Keep the roof's original stone slates in use
- Stone from other buildings
- Avoid where possible; check its source is legitimate
- Any shortfall
- Fill with newly cut Horsham slates where obtainable
Source: Stone Roofing Association, Horsham Stone Roofs; Horsham District Council, Storrington appraisal, fetched October 2026







