The short answer
Many old tiles can be reused, especially clay plain tiles and stone tiles that have weathered well. We inspect every tile during the strip, and any that are cracked, flaking or missing a nib go in the skip. The best survivors are relaid on the slopes people see, and matched new or salvaged tiles make up the shortfall. Concrete tiles are less often worth saving.
What decides whether a tile is worth keeping
A tile is reusable if it is whole, sound through its thickness and still hangs properly. We pick each one up when the roof is stripped, and the test is simple. Does it ring when tapped, or does it sound dull? Is the surface flaking away in layers? Are the nibs, the small lugs on the back that hook over the batten, intact?
Frost is the usual enemy. Clay that has taken in water and then frozen can shed its face in sheets, a fault called delamination. A tile that looks fine from the ground may be spent when you hold it. Moss alone does not condemn a tile, because it can be cleaned off, but a deep covering of lichen over a soft surface tells us the body is holding water.
Nail or peg holes matter as well. Old tiles were often hung on oak pegs or iron nails, and a hole that has widened or split along the grain will not carry the tile again. Those go to the skip however good they look.
Natural stone tiles, the heavy limestone ones found on Cotswold-style roofs, are sorted the same way. They are valuable, difficult to match and usually worth every effort to save.
Clay, stone, slate and concrete compared
Different coverings behave very differently when they come off a roof. The table sets out what we usually expect, though only a hands-on look can settle any given roof.
| Covering | Reuse prospects | Main reason tiles are lost |
|---|---|---|
| Clay plain tiles | Good if the body is sound | Frost damage, broken nibs |
| Clay pantiles | Good | Cracks from foot traffic, chipped edges |
| Natural stone tiles | Very worthwhile | Delamination, enlarged peg holes |
| Natural slate | Good | Nail holes that have rusted out |
| Concrete tiles | Possible, seldom worth it | Surface wear, brittleness, lost colour |
Clay tiles are the ones people most often ask about. Our general view is that if the clay is sound, reusing it keeps the roof looking as it was built. Concrete tiles are cheaper to replace outright than to sort, clean and relay, so the saving rarely justifies the effort.
Mixing salvaged tiles with new ones
Almost no roof gives back every tile it started with. The usual answer is a blend. The best of the old tiles are relaid on the front and most visible slopes, and the shortfall is made up with new tiles, or reclaimed ones from a salvage yard, chosen to match in size, profile and colour.
New clay looks sharper and more orange than weathered clay, and put in a single patch it stands out. We therefore spread new tiles across the roof in a scattered pattern or keep them to the back slope, where they are hidden from the street. After a few seasons the difference softens.
Where a roof carries a mix of tile sizes from past patching, we stack them by size and relay each batch in whole courses. Tiles of different lengths in one course would give the wrong lap, the overlap that stops rain driving through.
Where the house is a listed building or lies within a conservation area, matching the existing tile may be a condition of consent. Ask B&NES planning, and see our page on listed roof replacement for how that process runs.
What sits under the tiles still gets renewed
Reusing tiles does not mean reusing the roof. The tiles are one layer in a build-up, and the other layers wear out on a different schedule. Underlay is the membrane that backs up the tiles against wind-blown rain, and it is replaced in nearly every re-roof. Battens, the timber strips that tiles hang from, are renewed so they take fresh nails or clips and sit at the right spacing for the tile.
Rafters and other structural timbers are a separate matter. They are checked for rot and beetle, and anything weak is repaired or replaced before tiles go back. How that call is made is set out under replacing roof timbers.
Ridge and hip tiles are treated differently again. Under BS 5534:2014 a bedded ridge or hip needs mechanical fixings, since mortar by itself is not a reliable fixing. So even a roof that keeps every field tile will usually get new fixings on the ridge.
Cost, timing and the questions to put to a roofer
Reuse affects the price in two directions. You save on buying tiles, but sorting, cleaning, stacking and relaying take labour, and tiles on a heritage roof can be dear to replace, so the saving is often worth having. Where a modern concrete tile would be cheap to renew, it seldom pays.
Ask any roofer three things. How will the tiles be checked as they come off? What happens to the ones that fail? And where will the replacements go, front or back? A straight answer shows they have thought about it.
Stripped tiles also need dry storage and careful handling, since a tile dropped from the scaffold is one fewer. The same scaffold lets the chimney be dealt with at the same visit, which is the subject of chimney work while the roof is off.
We look at the tiles during the free survey and tell you what we expect to save. Your fixed price follows in writing. For the wider process, read about roof replacement with us in Bath.
