When does a repair stop making sense? Signs you need a re-roof

We get asked this question a lot. The honest answer is that there’s no single age at which a roof needs replacing. It depends on the material, the location, the original install quality, and how well it’s been maintained.

But there are signs. Once several of them show up together, the math stops favouring repair.

The age and material rule of thumb

As a rough guide:

• Concrete tiles: 40-60 years typical service life on a well-installed roof
• Natural slate (Welsh/Cornish): 80-150+ years
• Imported slate (modern Spanish/Chinese): 30-60 years depending on source
• Clay plain tiles: 60-100 years
• Felt underneath any of the above: usually 20-30 years regardless of tile

These are not promises. A poorly installed roof will fail earlier. A well-maintained one will last longer.

The telltale signs you’re at the tipping point

• You’re patching the same area repeatedly — three patches in five years is the threshold. After that, the surrounding material is failing just behind the patches you’ve already done.
• The roof is more patch than original covering — sometimes obvious when you look at it from the ground: a patchwork of new and old tiles in different colours and conditions.
• The ridge is failing — mortar flaking off, ridge tiles loose or visibly out of line. If the ridge is failing throughout, the rest usually isn’t far behind.
• The felt underneath has degraded — symptoms are damp in the loft, water marks on the back of the roof decking, daylight visible through gaps.
• Multiple slipped tiles after every storm — the fixings are giving up. Once a few nails corrode through, the rest follow quickly.
• Your roofer tells you the cost of repair exceeds the cost of the remaining service life of the roof — this is the simplest signal of all.

When a repair is still the right call

• The roof is otherwise sound and under 25-30 years old
• The damage is localised (one valley, one chimney, one section)
• The fixings throughout the rest of the roof are intact
• There’s nothing wrong with the felt or battens underneath
• The damaged tiles or slates can be matched

If three of those are true, repair is usually the right answer. If only one or two are true, re-roof.

What a proper re-roof actually involves

This is the bit most homeowners don’t see, because the tiles going on look the same as the tiles coming off.

1. Strip the existing roof — tiles, battens, felt, all of it. This is the messy bit.
2. Inspect the structure underneath — rafters, purlins, ridge beam. Any rotten timber gets replaced.
3. Renew the breathable membrane — modern breathable felt goes on, lapped correctly at eaves and ridge, with proper eaves ventilation.
4. Renew the battens — pressure-treated timber, sized for the tile or slate being installed.
5. Install the new covering — slate, tile, or flat-roof membrane. Each type has its own fixing pattern and ventilation requirement.
6. Renew flashings, valleys, ridge, verges — using the right material for the covering. Lead for slate, mortar or dry-fix for tile depending on age and budget.
7. Sort the gutters and fascia while we’re at it — much cheaper to do at the same time as the re-roof than later.

A proper re-roof on a typical 3-bed Bath semi takes 1-2 weeks depending on complexity. Scaffolding goes up, stays up for the duration, comes down at the end.

What it doesn’t usually involve

• New timber rafters (unless specifically required)
• New chimney stack (unless separately agreed)
• Internal work to ceilings (unless water damage has already happened)
• Re-plastering inside

If a quote includes a lot of extras beyond the re-roof itself, ask why.

The cost framing

We don’t publish prices for specific reason: every roof is different. A simple re-roof on a small bungalow is a very different job to a complex Victorian terrace with valleys, hips and dormers. We quote each job on its own.

What we can tell you: a re-roof is usually cheaper than three rounds of major patching over five years, and comes with a guarantee that patching doesn’t.

If you’re at the point of wondering whether it’s time, book a survey. We’ll look at the roof properly, write up what’s worth saving and what isn’t, and give you a fixed quote for whatever you decide to do.