Question answered
Hipped Horsham stone roofs
The short answer
A hipped Horsham stone roof slopes on all sides, with the slopes joined along sloping edges called hips. Steyning's conservation area appraisal says older buildings there usually carry Horsham slab or clay peg-tile roofs, many of them hipped. Stone courses from two slopes must be cut to meet at the hip, so hips take more skill, more stone and more care than the open roof.
On a hipped roof every side slopes away, and on stone each of those slopes has to meet its neighbour along a hip. That junction is where most of the skill sits.
What a hip is and why stone makes it harder
A hip is the sloping line where two roof slopes meet at an outward corner, that starts at the ridge and finishes at the eaves. A gabled roof ends in a vertical wall. A hipped roof ends in another slope, so there is no gable and a hip runs down each corner.
Tiles are made in standard shapes, and special hip tiles exist to finish the corner. Stone does not come that way. Each course on one slope has to be cut at an angle to meet the course on the next, and the cut pieces must still overlap the ones below. Since the courses shrink towards the ridge, a cut slate has to be chosen for its size and for its place.
That is slow, skilled work, and it explains why a hip can be the dearest few metres of a stone roof. It is also where a poor repair shows soonest.
Hipped roofs in Steyning and the villages around
Horsham District Council's Steyning Conservation Area Appraisal reports that older buildings in the town usually have Horsham slab or clay peg-tile roofs, often hipped, and that plenty of slab roofs still survive. If you own an older house there, you may well have a hip to look after.
The same appraisal counts relaying slab roofs with mortared joints among poor repairs. Henfield and Storrington, covered by their own council appraisals, record Horsham stone among their roofing materials, and Old Shoreham and North Lancing have examples on the Adur side.
Most of these roofs are old and have been patched. Horsham's own town appraisal notes double and single lap work side by side, with shadow slates covering the places where stone ran out. A hip on a roof like that is rarely the work of one hand, which is why we study it closely before saying what it needs, and why we keep the photographs of each repair we find.
Why mortar is the wrong shortcut on a stone hip
On modern tile roofs, ridge and hip tiles were once bedded on mortar alone. Since the 2014 revision of BS 5534, bedding alone no longer counts as enough for them, and they are fixed mechanically too. That standard is written for tile, though, and Marley points out that its 2018 amendment accepts the advice may not suit heritage roofs, suggesting a word with the planning authority and heritage specialists first.
For stone the lesson is different. Heaping mortar along a hip to hold cut slates is a common emergency repair, and it does harm. It traps water, hides the joint and sets hard, so the slates beneath crack when the roof moves, and a repair that was meant to last a winter ends up needing to be undone.
A better route keeps the stone free to drain, fixes each cut piece on its own fixing and lets the overlap of the courses keep rain out. Our page on mortar on stone slates goes further.
Checking a hip from the ground and up close
From below we look for a hip line that has dipped, for cut slates that have slipped or turned green, and for staining down the wall beneath, which can mean water is getting in along the hip. A sagging hip may point to the hip rafter or the timbers that carry it, because stone is heavy and a weakened frame shows first at the corners.
Up close we see how each cut is bedded, whether mortar has been added, and whether the courses either side still follow their pattern. We photograph all of it, so you can see for yourself what we are describing.
If the hip needs rebuilding, the existing stone should go back wherever it can. The Stone Roofing Association's order of preference is the roof's own slates first, and the page on whether to sell old stone slates explains why that stone should stay with the roof.
Listed hips and what consent covers
Many hipped stone roofs belong to listed buildings. Repairs in place that match the existing materials are treated differently from changes that affect the character of the roof, and the Adur & Worthing guide counts non-matching repairs as work needing listed building consent. Our guide to listed consent for stone roofs sets out the principles.
The Stone Roofing Association also says that converting a single-lapped roof to double lap calls for a review of the loading, building control approval and, on a listed building, consent from the council. A hip rebuild that alters the lap system is that sort of change, and it should be raised at the start, not halfway through.
Ask whichever authority covers your address before work starts: Adur & Worthing Councils, Horsham District Council or the South Downs National Park Authority. The wider service is on our Horsham stone roofing page.
Stone hips: two more questions
Why is my stone hip leaking when the rest of the roof is dry?
The hip is where the most cut pieces meet, and any one of them can slip, crack or lose its overlap. Added mortar can also hold water against the stone. Staining on the wall below is a clue, but we check the hip itself before saying what it needs.
Can a hipped stone roof be converted to a gable?
It is a structural change that alters the shape of the roof, so it needs the right approvals and, on a listed or conservation area house, a conversation with the council first. We would look at the existing frame before saying whether it is practical.
Tell us about your roof
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