Slate lasts generations — but the fixings under it don't. Why old slate roofs shed slates, how they're repaired without ruining the roof, and what to watch for.
A natural slate roof can last well over a century. What wears out first is rarely the slate — it's the nails holding it. That single fact explains most of what goes wrong with slate roofs across Kent, and most of what we're called out to fix.
Why Slates Slip
- Nail fatigue — iron nails corrode away over decades and the slate simply slides
- Wind — a gust on a loosely fixed slate lifts it and it goes
- Breakage — a dropped branch, a careless ladder, or foot traffic during other work
- Felt failure underneath — the slate looks fine but the barrier below has perished
How Slate Repairs Work
Individual slates are replaced using slate hooks or a crook — a technique that fixes the new slate to the battens without disturbing the surrounding ones. Done well, a repair is almost invisible and the neighbouring slates are untouched. Done badly, pulling out the tiles either side to reach the broken one can set off a cascade of failures.
Matching Matters
Slate varies enormously by origin — Welsh, Spanish, and reclaimed slate all differ in colour, thickness and texture. On an older roof, a mismatched slate stands out and, worse, can sit at a slightly different height, holding water against its neighbours. Reclaimed slate of the right type is often the right answer where new doesn't match.
When A Slate Roof Needs More Than Repairs
If slates are failing across a whole elevation, or the felt underneath has perished, patching becomes a treadmill. In that case, re-slating may be the sensible spend — though it's worth checking the battens and felt first, since a slate roof with sound structure can often just be re-slated and go on for decades more.
We repair and re-slate across Medway and Kent, matching original materials wherever we can. Free survey with photographs of anything failing.
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Costs and timings in this article are guides for Medway and Kent properties. Every roof is different — a survey is the only way to get an accurate figure.