Targeted repair
- Suits isolated cracks, slips or single damaged slates
- Keeps most of the original covering in place
- Matching may be limited by available stock
- Less disruption to the house and the roof
Roofing
Slate Roofs: Repair, Replacement and Matching
Natural slate is a durable covering split from quarried stone, and it can perform for many decades when well laid and maintained. Repairs need care, because slates are brittle and matching is not always straightforward.
About slate
What makes slate different
Slate is split into thin sheets from quarried stone, then fixed to the roof with nails, usually through a small hole near the top of each slate. Unlike many tiles, most slates are fixed with two nails, and each lower edge sits over the slate below. Quality varies between quarries and between batches, so a replacement slate may look different from the older ones around it.
Slate is heavy, and the roof timbers must support it. Nails can corrode over the years, which is one of the most common reasons slates slide or slip. We check the nails, the battens and the underlay as part of any slate survey, and explain what we find in plain language.
Repair or replacement
Individual slates can be replaced if they have cracked, slipped or been damaged, provided the new slate can be fixed without disturbing the sound slates around it. Where slates have been patched over the years with mixed materials, a planned replacement of a whole area can give a more even finish than repeated small repairs.
Where the damage is widespread, or the battens and underlay are failing, a larger area or a full re-slate is usually the better option. We set out the choice clearly, so you understand the effect on appearance, the work involved, and how long the repair is likely to hold.
Early warnings
Signs of slate trouble
Slate tends to fail in predictable ways. Noticing these signs early can keep a repair small.
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Slipped slates
Slates that have dropped out of line, or sit at an odd angle, often mean the fixings have failed. Slipped slates expose the battens and can let rain into the roof space.
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Staining inside the roof
Damp patches on the inside of the roof, or water running down the rafters after rain, suggest that slates or the underlay need attention.
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Uneven courses
Rows that look wavy or sagging can point to rafters that have moved or battens that have lost their line. A structural check may be needed alongside the covering assessment.
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Rust-stained nails
Rust staining visible on the underside of the slates can show that the nails are corroding. This is a sign the fixings may need replacing before further slates slip.
Assessment
Want a slate roof checked?
Our survey identifies slipped, cracked or poorly fixed slates and shows how they affect the rest of the roof. We set out a clear plan and the reasons for it, so you can compare options with confidence.
Options
Repairing or replacing slate
The right approach depends on the age of the roof, the condition of the fixings, and how closely the new work needs to match the old.
Area or full re-slate
- Suits widespread failure of fixings or battens
- Allows the underlay and battens to be renewed
- Gives an even finish across the affected area
- Involves more time, materials and disruption
The process
How slate repairs are carried out
Slate work is slower than many other coverings because each piece is handled individually.
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Survey
We record the condition of the slates, nails, battens and underlay, and mark each area needing attention so that the scope is clear to you.
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Sourcing a match
We look at the size, thickness, colour and texture of the existing slates. Reclaimed slate is often the closest match, and where it is not available we discuss the alternatives with you.
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Lifting and replacing
Slates above the damaged piece are carefully lifted, the broken slate is removed, and the new slate is fixed with suitable nails. Care is taken not to crack the surrounding slates.
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Renewing fixings and underlay
Corroded nails are replaced, and any damaged underlay or battens are repaired so the new slate sits on sound support.
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Final check
The repaired area is checked for alignment, fixing and lap (the overlap between rows), and we explain what we have done and what to watch for.
Maintaining a slate roof
Slate rewards regular attention. Keep gutters clear of slate debris, because blocked gutters can back water onto the verges and lower courses. Look at the roof from the ground after storms for slipped or missing pieces, and note any sagging lines so they can be checked. Moss can hold moisture against slate, so growth should be dealt with carefully, and we can advise on a suitable approach for your roof.
Keep a record of any repairs, including the date, the area and the type of slate used. That information helps whoever works on the roof next, and it makes a future repair easier to match. Please do not walk on a slate roof to inspect it. Slates are brittle and can break under foot, and a broken slate is often the start of a larger problem.
Related
Related roof coverings
Questions
Slate roof questions
Answers to common questions about slate repairs and replacement.
Can you find slate to match my roof?
We look at the existing slates first. Reclaimed slate is often the closest match, but availability varies, and we cannot promise an exact match for every roof. We explain what is possible and the likely visual difference before work begins.
Why do slates slip off when they look fine?
Slates are held by nails, and those nails can corrode or break over time. Once the fixings fail, a slate can move or slide even though the slate itself is sound. A survey checks the fixings across the affected area.
Is slate more expensive to repair than other coverings?
Slate repair is labour intensive because each piece is handled individually, and matching adds to the work. The cost depends on the size of the area, the access and the availability of suitable slates. We provide a written explanation of the scope so you can compare options.
How long does slate last?
Natural slate can last a very long time when it is sound and well fixed, but nails and battens are often the first parts to need attention. Regular checks help you spot problems early. We cannot promise a fixed lifespan for any roof, as conditions vary.
Should I wait until slates start falling before acting?
No. A slipped slate can allow water into the roof space, and it can fall onto people or property below. Keep clear of the area beneath any damaged part and arrange an inspection as soon as you notice a problem.
Where we work
Roofers serving five regional areas
We work across five regional areas: North London, North West London, West London, Hertfordshire, Buckinghamshire. Not sure if we cover your street? Call us on 01632 960123, or see all areas we cover.
Next step
Book a slate survey
If you have spotted slipped or cracked slates, contact us to arrange an inspection. You can reach us through the contact page.