The short answer
Patch a tiled roof where the fault sits in one spot and the underlay and battens beneath are sound. Plan to re-tile when slipped or cracked tiles are widespread, the underlay has failed or the battens are rotten, because those faults sit under the covering and spread. The decision is made from the loft as much as from the roof, using photographs, not guesswork from the ground.
When a patch repair is the right answer
A patch means replacing or refixing individual tiles, renewing a stretch of ridge or repairing a flashing, and leaving the rest. It suits a single cause or weak point, such as a tile cracked by a falling branch, a ridge whose mortar has dropped out, or a valley lining with a split.
Everything turns on what lies underneath. With firm battens and intact underlay, a few new tiles put the roof right and give it more years for modest outlay. MyBuilder's 2026 repair guide gives minor repairs at £100 to £300 and moderate ones at £500 to £1,000, with major repairs at £2,500 and above, as national typical ranges. Our written quote after the survey sets out the repair clearly, so the scope of a limited patch is easy to follow.
Signs a tiled roof has outlived patching
Three problems tip the balance towards a re-tile. The first is slipped or cracked tiles across a whole slope, not a handful. The second is failed underlay, with splits, rotted laps or sagging felt. The third is rotten battens, which cannot be reached without lifting the tiles. For what the smaller repairs run to, see tiled roof repair costs.
Other signs add weight: tiles that crumble or flake at the surface, moss that holds water against the lap, daylight through the covering seen from the loft, and repeat leaks in new places after each repair. Patching a roof in that state is like darning a worn jumper, since each mend puts strain on the weaker wool beside it. Clay and concrete tiles are quoted at decades of life, yet how the roof has fared matters more than the year it went on.
How roofers decide
We start outside, using a ladder and camera to judge the courses, the ridge, the hips and valleys. Next comes the loft, where we examine the underside of the covering, the battens, the rafters, the insulation and the eaves. The loft often shows what the roof surface hides.
The judgement is then one of economics and risk. If a patch would need scaffold anyway and the next failure is likely within a few years, paying twice for scaffold costs more than doing the slope once. Checkatrade's repair guide gives concrete tile repair at £90 to £120 per m² and clay at £110 to £160, ex VAT, and MyBuilder puts a full re-roof at £5,000 to £12,000 for typical houses, with Checkatrade's range running higher. These are national ranges; what you are quoted depends on access, size and the covering.
What a re-tile involves and what it triggers
A re-tile strips the slope, renews the underlay and battens, then lays the tiles back or lays new ones. Sound old tiles are often reused, with new ones filling the gaps. A covering of different weight needs a structural check under Approved Document A where it is around 15% heavier.
A re-roof touching under 25% of the building envelope and under 50% of the roof normally sits outside Building Regulations approval. Go past either limit and approval applies, with Part L possibly requiring better insulation in the roof. Our guide to insulating at rafter level sets that out. We explain the consent position and manage the notification where work is notifiable.
Low pitches, old coverings and getting a plain answer
A low-pitch roof can be a special case. A tile used below its maker's minimum pitch will leak however often it is patched, so our answer on low-pitch tiled roofs is worth a read first. On an older house, we aim for like for like, so a clay roof stays clay.
Send us photographs of the slopes and anything you can see from the loft. After the survey you hold photographs of your roof and a written quote. Workmanship is guaranteed for 10 years in writing, and we tidy up and carry the waste off. More options sit under pitched roofing.
A worked way to compare the two options
Ask for the quote in two parts: the patch repair, and a re-tile of the worst slope. Put the cost of scaffold in both, because it is the item people forget. If the patch is a fraction of the re-tile but you expect to be back within a few years, the maths often favours doing it once.
Then weigh what else you may want from the roof. A re-tile is the natural moment to replace the underlay, add ventilation where the roof needs it, refix the ridge to current practice and, if the work is large enough, improve the insulation. A patch cannot do any of that. On the other hand, a roof with sound timber and a handful of damaged tiles gains little from being stripped, and the survey report states that plainly.
What to ask a roofer about the choice
Ask what the timber looks like from the loft, and ask to see it. A roofer who has only been up a ladder cannot judge battens or underlay. Ask how many tiles are affected, and whether the cause has been found, because replacing tiles without finding why they slipped usually means a repeat visit.
Ask, too, what a patch will not fix. A repair addresses the spot it covers, and a guarantee on it covers that work alone, so you should know where the remaining risk sits. Finally, ask for the alternative priced in the same layout, so the figures can be set side by side without translating between two formats.