In 40 seconds
Structural chimney repair in the UK covers a wide range of jobs. Repointing a chimney typically costs around £300–£1,000 depending on size and access, with around £750 common. Flaunching — renewing the mortar bed at the top of the stack — is often a few hundred pounds on its own, and lead flashing where the stack meets the roof usually runs £400–£1,500. A full stack rebuild is the big one, commonly £2,000–£10,000+. Removing a chimney stack is notifiable work under the Building Regulations. Because all of it happens at roof level, it is working at height and normally needs scaffolding. The honest answer is always a range, because it depends on your chimney's size, condition and access.
Most chimney-repair guidance is published by firms doing the work, so the numbers tend to be optimistic and the rules glossed over. The pages below give honest cost ranges for repointing, rebuilding, flaunching and removal, explain the signs your chimney needs work, and set out the scaffolding and Building Regulations rules — before you take a single quote.