A Victorian or Edwardian slate roof is a simple, hard-wearing piece of building, and most of its faults are small ones that show long before the roof is finished. A slate hangs from a timber lath or batten by one or two nails. Each slate overlaps the course below it, so rain runs off the face and never meets a nail head. Lead seals each junction with brickwork or another slope, and a row of ridge tiles caps the top. Nothing in that system is complicated, which is why it can last so long.
The same simplicity means the weak points are predictable. The iron nails rust, the lead tires, the stack mortar cracks and the ridge loosens. Near the sea, a gale tests all four. A good repair deals with the weak point it finds and leaves the sound slates where they are, because old Welsh slate is the main reason the roof looks the way it does.
Below we cover what these roofs are made of, what to look for from the street, when to repair and when to re-slate, how to match a period look, what consent may apply, and how an exposed seafront site changes the fixing.
What a period slate roof is built from
Most of the weather protection on these houses comes from the slates themselves, laid in straight courses with each one overlapping the two below it. Behind them sits a timber frame: rafters running up the slope and, across them, the battens that every slate is nailed to. Older roofs often have no underlay beneath the slates at all, so you can see daylight and the backs of the slates from the loft. That is normal for the period and it is not a fault in itself, though it means a slipped slate lets rain straight into the roof space.
The slates were fixed with nails, usually iron or another metal that rusts, driven through a hole near the top edge. Rust is the root of most slipped slates, and our short answer on nail sickness explains the process. A tingle is a strip of metal that holds a slate in place after a nail has failed, and the answer on slate tingles covers when one is a sound fix.
Lead appears wherever the slope meets something else. The valley is the trough between two slopes that meet at an inside corner. A soaker is a folded lead tab tucked beneath the slates next to a wall or stack, and a flashing is the lead band that closes the gap against the brickwork. At the apex runs the ridge, while the hips are the sloping edges at the outer corners. Decorative clay ridge tiles, finials on gable ends and tall brick chimney stacks complete the picture.
MyBuilder quotes Welsh slate as something that regularly lasts over a century. The slate is rarely what wears out first. The fixings, the lead and the mortar usually go before the stone does, and those are the parts a repair replaces.
Reading the roof from the pavement
Binoculars and a clear stretch of pavement tell you plenty, and a surveyor begins in the same place. Look along the courses first. Straight lines mean the roof is sound. A slate that has dropped a few centimetres leaves a visible gap or a darker tongue of the slate underneath, and a run of them across one area suggests the nails in that section have given up together.
Next look at the colour and surface. Slate that is flaking, splitting into thin layers or turning soft and rusty is ageing from within, and the answer on delaminating slates explains why. Pale green moss on a shaded slope is mostly cosmetic, though thick growth holds water against the nails.
Where age shows first
Check the chimney stacks: white mortar crumbling out of the joints, a leaning pot or a cracked collar of mortar at the top. Check the lead at the stack and along any wall, because it stretches and cracks with the weather and can lift at its edge. Look at the ridge for gaps between the tiles or tiles that have shifted. Look at the valley gutters between a main roof and a rear projection, since a blocked or split valley can soak a ceiling in one storm.
Finally, look at the gutters and downpipes. On many Victorian terraces the gutter sits on the front wall under a parapet or behind a brick upstand, so overflowing water can find its way into the wall face and surface as a stain just under the ceiling.
From inside, a torch and a daylight visit to the loft help. Pinpricks of light mean a gap in the covering, and pale rings on the timber show earlier wetting. Photograph what you see. Written down or photographed, it gives a roofer a head start.
Repair, patch or re-slate
The right answer depends on what is failing. If a handful of slates have slipped because their nails rusted, the roof is usually repairable: the loose slates are re-fixed, broken ones are replaced with matching slate, and the courses around them are checked. Our guide to slate roof repairs goes through the method.
Repair stops being sensible when the nails are giving way across an entire slope. Slates then keep slipping a few at a time, each repair costs a scaffold or a ladder visit, and the total soon passes what a proper re-slate would have cost. A roof in that state is better stripped, battened, re-lined and re-laid, reusing as much of the original slate as is sound. A surveyor can tell the two situations apart by lifting a few slates and looking at the nails.
For typical figures, MyBuilder (updated 21/08/2026) gives a slate re-roof as £100 to £180 per m², and Checkatrade (table last updated June 2026) gives repair costs for natural slate of £150 to £220 per m², exclusive of VAT. Both are national typical ranges. On a period house the price moves with access, the height of the building, how much slate can be reused and the amount of lead and chimney work involved. After the survey, the quote is written down with a single price; when comparing offers, find out whether it covers VAT and scaffolding.
A repair that fits the fault is usually the right first answer, but ask to see photographs of the nails and battens before agreeing to either route.
Keeping the period character
The look of a Victorian slate roof comes from a few things that are easy to lose by accident. The first is the slate itself: its colour, its thickness and the slightly uneven surface of hand-split stone. New slate from a different quarry can be flatter and a different shade, so a patch of it stands out for years. Where a roof needs substantial new slate, reclaimed material of a similar size and colour is often the better match, and our guide on reclaimed slate covers how it is sourced and what to check.
The second is the layout. Many period roofs use diminishing courses, where the slates get smaller towards the ridge, and a few use graded sizes in neat bands. A re-slate that flattens this into uniform courses changes the roof from the street.
The third is the detail. Decorative ridge tiles, finials, lead rolls and the way the slate meets the chimney all belong to the building. Replacing them with plain modern parts is quicker and cheaper, but it takes character out of the roof.
Matching the fixing to the building
BS 5534 sets the current recommendations for slating, and the A2:2018 amendment accepts that the code can be a poor fit for heritage roofs, pointing you to the planning authority and conservation specialists first. For a period roof that usually means keeping the original lap and batten spacing, choosing fixings to suit the exposure, and dressing lead to suit the existing profile. Keeping the original pattern of fixings also matters, since the visible rhythm of the courses is part of the look. A good repair is one you cannot see from the road.
Conservation areas, Article 4 and listed buildings
Some of the Worthing, Hove and Adur streets with these roofs also sit in a conservation area. A conservation area does not stop you repairing a roof. Replacing a roof in the same material and appearance generally sits outside planning control, with a listed building and any Article 4 direction as the caveats to check first.
An Article 4 direction withdraws specified permitted development rights in a defined area, so that work which would normally be allowed needs an application. The councils explain that in certain conservation areas their directions take away the usual freedom to change features including roof tiles and windows. Those we have opened are specific. In Old Shoreham and Kingston Buci, changes to roof coverings are removed from permitted development where the roof faces a street or public path, and chimney and flue work needs an application anywhere on the plot. In Warwick Gardens, Worthing, altering what a roof slope facing a road or open space is made of, or how it is formed, needs permission. The Warwick Place and Western Row directions also reach roof alterations. Check the position for your street with the Adur & Worthing planning team before you plan a change of material.
A listed house raises the stakes on materials. Under the council's guide a repair that does not use matching materials needs listed building consent, while sensible upkeep does not. The National Park Authority draws the same line: small repairs carried out on the spot using the original material are fine, while replacing historic fabric can need consent. Our guide to slate roofs in conservation areas sets out the consent route in more detail.
Fixing a seafront slate roof so it holds
A period slate roof within sight of the sea takes more punishment than the same roof inland, and the fixing is what decides whether a repair survives a gale. The two things that matter most are how far each slate overlaps the one below, called the headlap, and how it is held. On a steep slope the slate hangs on nails. On shallow pitches, hooks are a poor choice, and Cupa Pizarras advises against hooks on any slope shallower than 25 degrees. The page on fixing slates in exposed coastal sites explains the headlap table and the decisions behind it.
It is worth saying plainly that we cannot give you an exposure category for a named street from a desk. The right fixing specification comes from the site, the height of the building, the pitch and the slate size, and from the manufacturer's data. Close to Shoreham airport the manufacturer's own fixing specification may call for specialist advice too.
What we do on the day
We lift a few slates to see the state of the nails and battens, then show you photographs of what we found. We suggest the smallest repair that cures the fault. You get a single-figure quote in writing and a clear site at the end, with any sound old slates you want to keep set aside for you.
If you are weighing up a repair on a period house in Worthing, Shoreham or Hove, send photos of the front elevation and the loft, and we will say where we would begin. Our slate roofing page covers the wider service.
