A sound natural slate roof is a tough thing. Slates overlap each other, they shed water quickly and they do not soak it up the way some other coverings do. Storms still expose weakness. A gust lifts a slate whose nails have corroded, a hard frost opens a hairline crack, and rain that arrives sideways finds the one place where the lap is thin.
This guide is about weather and what it does, not about who pays. It explains how wind and frost act on slates, how to spot storm damage from the ground, what a roofer does first when a slate roof is leaking in bad conditions, and when to wait for better weather. If you want to know how an insurer treats a slipped slate, there is a separate answer on slate roof insurance. For the whole service, see our slate roofing page.
How wind works on a slate roof
Wind does two things to a pitched roof. On the windward slope it pushes air under the lower edges of the slates, and on the leeward side and around the ridge it creates suction that tries to lift the covering away. Slates are heavy for their size and each one is nailed, so a healthy roof resists both. The damage tends to happen at the weakest fixings.
Where wind finds a way in:
- Corroded or fatigued nails. A slate whose nails have thinned has little holding it down. This is the most common route to a slipped slate after a gust, and our answer on nail fatigue explains the mechanism.
- Edges and corners. The verge (the edge along a gable), the eaves and the ridge take the strongest uplift, which is why the bedding there is held with mechanical fixings.
- Thin headlap. The headlap is the overlap of a slate over the one two courses below. If it is too small for the roof's exposure, rain can be driven past it.
- Unfixed or poorly fixed repairs. A replacement slate pushed into place with a dab of sealant can come off in the next stiff wind.
Exposure also matters. BS 5534 treats an address as one of moderate or severe exposure, and Cupa Pizarras adds that land within 30 miles of a coastline facing west counts as severe. Whether your address falls in that band is something we check against the guidance before setting the headlap on a new roof, because a headlap that suits a sheltered lane may be too shallow for a roof that takes the full force of a gale.
What frost does to slate
Frost damage is slower and quieter than wind damage. It works on water that has already got into the stone. When that water freezes it expands, and a slate that is cracked, laminated into thin layers or holding moisture can split further with each freeze and thaw.
Natural slate has a reputation for being very dense, which is why it lasts so long. MyBuilder (2026) gives natural slate 80 to 100 years or more. Slate varies, though, between sources and between individual pieces. A poor slate, or one starting to delaminate (peel into thin flakes along its layers), takes in water, and frost makes a weak slate weaker.
Moss and standing water
Moss holds moisture against the surface, and in a cold snap that water freezes in place. Moss also lifts the edges of slates slightly and fills the gaps between them. Where it blocks a valley or gutter outlet, water backs up and freezes there. The moss itself is not the problem for the slate; the standing water around it is. Our answer on moss on a slate roof covers when to remove it.
Gutters and valleys in a freeze
Ice in a gutter can force joints apart and pull brackets away from the fascia. A frozen valley can push water up beneath the slates on either side. On a hillside terrace, where a long roof drains into a single gutter run, a blocked outlet shows up quickly as an overflow down the wall. We clear and check these during a winter visit because a blocked gutter can cause the damp that is blamed on the roof.
Reading the damage after a storm
You do not need to go up to find storm damage, and you should not. From the ground, in daylight, the signs show.
- Gaps and dark patches. A missing slate leaves a dark rectangle where the batten and underlay show through.
- Slipped slates. A slate that has slid down hangs lower than its neighbours, with its tail below the line of the course.
- Debris. Pieces of slate in the garden, on the path or in the gutter point to broken slates above, and slivers lying under a particular slope tell us where to look first.
- Ridge and hip pieces. Look for ridge tiles that have shifted, tilted or gone.
- Flashings. Lead that has lifted at the chimney or against a wall.
Inside, check the loft and the top-floor ceilings. A damp patch, a drip or a smell of wet plaster means water has already entered. A pair of binoculars helps from the pavement, and a phone photograph taken with the zoom is useful to send us, since it lets us judge whether the visit needs scaffold before we arrive.
Photograph first, then call
Photograph damage from a safe spot before anything is moved or repaired. Those pictures help us plan the visit, and they help if you decide to claim on a policy; the process for that is set out in our roof insurance claims guide. We prioritise leaks and storm damage, yet the first visit only aims to stop water getting in. The full repair waits until the roof is dry and the damage is understood.
Keep off the roof and away from the ground beneath it. Loose slates can fall without warning after high winds, and wet slate is slippery.
Making a leaking slate roof safe in bad weather
A make-safe is not a repair. Its job is to stop water entering and remove danger, so that the proper repair can happen in suitable conditions. What that involves depends on what has happened.
Loose slates and falling hazards
Slipped or cracked slates that could fall are removed or secured, and the area below is cordoned off if needed. If a ridge has come loose, it may be taken off or fixed back until the repair.
Temporary cover
Where slates are missing and rain is entering, a temporary covering goes over the exposed area. That is normally a heavy-duty tarpaulin or sheeting fixed down over the batten line or secured with battens clamped across it, so wind cannot lift it. The cover needs to run over the ridge or well above the damage and be fixed so that it sheds water rather than collecting it. A tarpaulin weighed down with a few bricks does not stay put in a gale.
Interior protection
If water is already coming through, there may be a need to protect the room: moving belongings, laying sheeting, or opening the loft hatch to see where the water is entering. We advise on that by phone where we can. If there is any sign of water near electrics, switch the circuit off and call a qualified electrician.
Scaffold or ladder?
A tarpaulin on a low roof can sometimes be fitted from a ladder or a platform. On a tall terrace or steep hillside house, or where more than a few slates are involved, scaffold is safer. MyBuilder's 2026 re-roof figures put scaffold at about £1,125, and scaffold can also be hired for a repair. Scaffold is allowed for in the quote, so you know the figure before anyone climbs.
Winter repair: what can be done, and what should wait
Slate repairs can go ahead in cold weather, but conditions set limits. Wet, icy or windy conditions make work on a roof dangerous, and we will not put a person on a roof that is unsafe to stand on.
What can be done in winter
- Replacing individual slipped or broken slates, with fixings suited to the pitch.
- Refixing ridge tiles and hips, using mechanical fixings.
- Patching flashings with lead where the surface is dry enough.
- Clearing gutters, hoppers and valleys, so that meltwater and rain have a clear path off the roof.
What is better in drier conditions
Anything involving mortar or lime, such as re-bedding a ridge or repointing a chimney, needs conditions where the mortar can set without freezing or washing out. Larger jobs such as stripping a whole slope should have a weather window, because an open roof needs to be closed again when work stops for the day, and a run of storms can delay the work for days.
A safe temporary repair now, a proper one later
If the weather is bad and the damage is minor, a temporary repair buys time. We then come back to do the proper work in good conditions. On a roof that needs a full re-slate, there is no reason to rush a decision made in the middle of a storm. Our slate fixing methods guide describes the fixings used on repairs and re-slating alike.
Repairs carry our written 10-year workmanship guarantee, and broken slate and rubbish leave with us.
What storm repairs cost, using published ranges
Storm repair prices depend on the damage and the access. National cost guides give ranges you can compare with a quote.
| Job | Typical UK range | Source |
|---|---|---|
| Single slate replaced | £60 to £120 | MyBuilder, 2026 |
| Five to ten slates | £150 to £350 | MyBuilder, 2026 |
| Minor roof repair | £100 to £300 | MyBuilder, 2026 |
| Storm damage fixes | £500 to £1,500 | MyBuilder, 2026 |
| Ridge or hip repointing | £200 to £400 | MyBuilder, 2026 |
These are national figures from a cost guide and are not our prices. They show the scale: a few slates can be a modest job, while damage across a slope, or a roof with failing fixings throughout, moves toward a larger repair or a re-slate. Our full guide to slate roof costs covers re-slating per square metre, which MyBuilder puts at £100 to £180.
Why a survey beats a guess
The price of a storm repair is not known until someone sees the roof. We survey, photograph the slope and write a quote that covers the repair, the access, any lead or ridge work and the waste. Your quote shows VAT, which for general roofing work is normally added at the standard rate.