The short answer
You can buy mortar and a pointing trowel, but repointing a chimney is a work-at-height job on the most exposed point of the roof. A ladder on slates is not safe, scaffolding costs real money, and the wrong mortar damages the brick. Much of what a roofer charges is access and judgement, which is why doing it yourself rarely saves what people expect.
Why a chimney is not a garden wall
Repointing a garden wall is patient, low-risk work. A chimney stack is the opposite. It rises from the ridge or the slope, usually well above the highest point you can reach from a ladder, and the job happens at arm's length from an edge. Falls from roofs and ladders are among the most serious accidents in home maintenance, and the Health and Safety Executive treats work at height as a hazard in its own right.
A stack also has more going on than its joints. Flashing, flaunching, pots and cowls all meet in a small area, and someone holding a bag of mortar may not notice a lifted lead flashing or a cracked cap. Fixing the joints while the real fault goes untouched is the usual way to pay for the same job twice.
The access problem
A ladder against the gutter does not reach a chimney. Roof ladders hook over the ridge and rest on tiles or slates that were never designed to carry a person, so slates crack and tiles slip, and a damaged roof is a bigger repair than a damaged stack. Proper access means scaffolding, and a safe scaffold on a chimney is a skilled setup.
MyBuilder's scaffolding guide, updated in August 2026, gives £400 to £900 for chimney-height scaffolding, and Checkatrade's February 2026 guide quotes about £660 a week. Hiring and erecting that yourself often costs more than it saves. Our page on chimney scaffolding explains the options.
A roofer arrives with the equipment and the practice to use it. A large share of a professional repoint pays for exactly that, which is why the price can look high against the cost of the mortar.
Getting the mortar wrong
The mix matters more than the technique. Old brick is often softer than modern cement mortar, and a hard mix forces frost and rain to attack the brick rather than the joint. The result is spalling, where the faces flake away, so a stack that looks smart for a couple of winters then begins to fail. Repointing a second time costs the same access again, which is the expensive lesson.
Lime mortar suits many older stacks, though it needs the right sand, the right weather and careful curing. Pointing in frost or rain ruins a day's work, and fresh joints have to be protected while they set. Our guide to lime mortar on chimneys explains why the material is chosen to suit the brick.
Raking out needs care too. Cut too deep and you weaken the stack, too shallow and the new mortar will not key in. Both mistakes are easy to make and hard to spot from below, and you only find them when water appears indoors.
What professional repointing costs
MyBuilder's chimney repair guide, updated in August 2026, gives about £750 as a typical repointing price, within a range of £500 to £2,000. By house it lists £200 to £700 for a bungalow, £600 to £900 for a semi with a side stack and £900 to £1,500 where the chimney sits centrally. MyJobQuote's September 2026 guide gives a lower £250 to £350 for a standard stack, so the guides do not agree.
Treat all of these as national ranges, not what we would charge. Our figure comes after a survey, as a written total built on photographs of your own stack. Whoever you ask, find out if the quote includes scaffolding and VAT. Professional repointing also carries a 10-year workmanship guarantee from us, in writing, which a home attempt cannot offer.
What you can safely do from the ground
There is plenty a homeowner can check without leaving the garden. Look at the stack through binoculars after rain. Check the loft for damp stains near the chimney breast, and the ceilings below. Photograph the brickwork, the flashing and the cap, and note the dates so you can show whether anything is changing. Our page on chimney leaks lists what to look for.
If an aerial or dish is fixed to the stack, mention it when you call. Our notes on an aerial on a chimney explain how fixings loosen masonry. A good survey starts from what you have already seen, so send the pictures with your enquiry. If the stack serves a fire you still use, tell us, because a sweep may need to check the flue once the joints are sound. Dates, angles and a note of where the damp showed indoors all help us plan the right access before anyone is on the roof, and that can shorten the time needed on site.
Deciding between a repoint and something bigger
Part of a roofer's job is judging whether repointing is enough. Where the brick is healthy and just the joints have eroded, a repoint is the right-sized job, and often the most economical one. If the faces are flaking, the stack leans, or the mortar crumbles to sand when scratched, patching joints may only delay a larger repair. We say which applies and attach the survey pictures behind that view.
When the stack is tall and the roof is steep, the chimney repairs hub explains the full range, and the survey finds out which applies. Afterwards the site is left clear, with the debris removed. Scraps of old mortar and dust from raking out go with it, which matters on a roof where loose debris blocks gutters and valleys.