Reclaimed slate
Can old roof slates be reused when re-roofing?
Sound slates can go back on a re-slated roof, but each one is judged on its own. Here is how they are sorted, and what else has to be renewed.
The short answer
Yes, old slates can be reused when the roof is re-slated, provided each slate is sound. A slate that has flaked, gone soft or cracked is rejected, and the good ones are graded by size and laid again on new fixings, with battens and underlay replaced wherever they are weak or torn. HomeBuilding gives reclaimed Welsh slate an approximate lifespan of 50 to 80 years, against 100+ years for new Welsh slate, so a reused slate is judged as a used one.
5 min read ยท Part of Slate roofing
Which slates go back and which do not
Reuse starts with sorting. Each slate comes off by hand and is looked at on both faces and along its tail, because a fault on the underside is invisible once the slate is up. MyJobQuote counts slates that flake, split into layers or feel soft under the finger as a reason to consider replacing the roof, and a slate in that state is not worth fixing again.
- A firm slate with clean edges and no layers lifting goes back.
- A slate with a crack or a broken corner is set aside.
- A flaking or soft slate goes in the skip.
- Sound slates are stacked by size so each course can be laid evenly.
Slates are cut and laid in courses of matching length, so a pile of mixed sizes is no use until it has been graded. Any gap between what the old roof gives back and what the new roof needs is filled with reclaimed slates chosen for size, thickness and colour, or with new ones. Where the front of a house is on show, the colour of the replacements matters as much as the size, and they are chosen against the slates that stay.
How reclaimed slate compares with new
Published lifespans are approximate and differ by type. HomeBuilding's table, last updated 30 September 2025, gives these figures for the slate itself.
| Slate | Lifespan (approx) |
|---|---|
| Welsh slate | 100+ years |
| Spanish natural slate | 75 to 100 years |
| Reclaimed Welsh slate | 50 to 80 years |
Read them as ranges for the slate, never as a promise for the roof. A reused slate has already served one roof, which is why its range sits lower. That is no reason to throw a sound slate away. It is a reason to be strict about which ones are kept, and to ask whether the existing slates can serve a repair before agreeing to a full replacement.
Reuse also has a practical side on an older house. Slates that match the rest of the street keep the roof looking as it always has,. What it cannot do is make up for tired timbers beneath it, which is why the build-up under the slates is checked at the same visit, and why the survey looks at the battens and the lining as closely as at the slates themselves.
What is renewed underneath them
Slates are held by fixings into timber battens, and according to MyJobQuote it is often the fixings that give up before the slate does. Hanging old slates on old nails would put the same weakness back on the roof. When slates are reused, every fixing is replaced, so each slate is carried on new metal.
The rest of the build-up is looked at in the same spirit:
- Battens that have gone soft, or are too weak to hold a fixing, are replaced.
- The lining under the slates is renewed where it is torn or past its best.
- The eaves detail is rebuilt to suit the new courses.
- The fixing specification is set for the site, with exposure in mind.
Taking the roof back to the timbers is also the moment to see what the old covering was hiding, such as a rotten rafter end or a damp wall plate. Finding it now costs far less than finding it after the slates are back on.
Our guide to re-slating or repairing shows how that decision is made. Our answer on nail fatigue explains why renewed fixings matter.
Rules around a re-slate with reused slates
Reusing the same slates does not switch off the usual checks. Under the Planning Portal's test, no building regulations application is normally needed while less than 25 per cent of the building envelope and less than 50 per cent of the roof is affected, so a larger job than that brings an application with it. In the Dover district, Dover District Council's building control page counts a change of roof covering, even a like for like one, as work that needs approval, so we confirm the route with the council first.
Planning is a separate test. The part of the permitted development rights that deals with re-roofing a house is Class C, but an Article 4 direction can take that right away, and a listed house adds a consent of its own wherever the work would alter its special interest. Putting the original slates back can help an older roof keep its look, which matters most on the slope that faces the street, and it is worth raising with the council before work starts if there is any doubt about the house's status. Our slate roofing page describes the wider work, from survey to written price.
More questions
Can I buy reclaimed slates to patch a roof?
Yes. A patch can use reclaimed slates sorted for size, thickness and colour, so the new slates sit well beside the old. The same checks apply as for slates kept from your own roof: no flaking, no soft edges, and a size that suits the course.
Do reused slates need a longer overlap than new ones?
Not as a rule. The overlap comes from the roof pitch, the slate size and the exposure of the site, as Cupa explains, and it is set once the survey has measured them. A slate that is sound and the right size can be laid to the same overlap as a new one.
Tell us what's wrong with the roof.
You'll get one written total price.