In 40 seconds
Roof leadwork — the flashing, soakers and valley work that seals the joints between a roof and chimneys, walls and other surfaces — typically costs around £40–£70 per metre fitted for replacement lead flashing. Re-flashing a chimney commonly runs £200–£600, rising to roughly £700–£1,000 once scaffolding is needed on a two-storey house. The grade of lead is set by its code: Code 3 to Code 8, where the number reflects thickness and weight (Code 3 is 1.32mm, Code 4 is 1.80mm, Code 5 is 2.24mm), with heavier codes used for more demanding work. Properly installed to Lead Sheet Association guidance, rolled lead can last 60 to 100+ years — far longer than the lead-look mortar and sealant alternatives. The honest answer is always a range, because it depends on your roof, access and how much lead needs replacing.
Most leadwork guidance is published by firms fitting it or selling the lead, so the numbers can be optimistic and the codes glossed over. The pages below give sourced cost ranges, explain the lead codes plainly, set out what re-flashing a chimney involves, and cover how long lead really lasts — before you take a single quote.