If you have booked a chimney rebuild in London, you are probably wondering what actually happens once the work starts. Will there be lots of mess? How long will it take? What are those workers doing up on the roof all day?
This guide walks you through a chimney rebuild from start to finish, in plain steps, so you know what to expect. If you are not yet sure whether you even need the work, it is worth reading about the warning signs your chimney needs rebuilding first, then coming back here to see how the job is done.
What is a chimney rebuild?
A chimney rebuild means taking down some or all of the chimney stack and building it back up again with new bricks and mortar. The stack is the part of the chimney you can see above the roof. Over the years, wind, rain and frost wear away the bricks and the mortar between them. Once that damage goes too far, a repair is not enough and the safest fix is to rebuild.
A rebuild can be full or partial. A full rebuild takes the stack right down and builds it again. A partial rebuild only replaces the top few rows of brick that have worn out. Your builder will tell you which one you need after they have taken a proper look.
Step one: the survey
Every good job starts with a close look at the chimney. A builder will check the brickwork, the mortar, the lead around the base and the chimney pot. They will often take photos so you can see the problem for yourself, since most people never get a clear view of their own roof.
After the survey you should get a written, fixed price quote that names the materials, the method and the timescale. This means you know the cost before anyone starts, and there are no surprises later.
Step two: scaffolding and permits
A chimney sits high up, so the team needs safe access to reach it. That is where scaffolding comes in. The scaffold is built around the side of your house so the workers can stand safely while they work.
If the scaffold needs to sit on a pavement or the road, or if a skip is needed for the old bricks, your builder will usually sort out the council permit for you. In many parts of London this step matters, so it is good to check it is included. Scaffolding normally goes up a day or two before the main work begins.
Step three: taking down the old stack
Once the scaffold is up, the team carefully takes down the worn brickwork. This is done by hand, brick by brick, not knocked over in one go. Working slowly keeps your roof safe and stops bricks falling where they should not.
The old bricks and rubble are cleared away as the team works, often into a skip or bags. A sheet is usually laid over the roof and around the base to catch dust and bits, which keeps the mess down.
Step four: the new brickwork
Now the stack is built back up. The team lays new bricks in fresh mortar, checking with a level as they go so the stack stands straight and true. Where they can, good builders match the new bricks to the ones on your house so the finished chimney blends in rather than sticking out.
If your home is in a conservation area or is a listed building, there can be extra rules about how the chimney looks and how tall it can be. The government backed Planning Portal explains the rules on chimney height and permitted development, which is worth a quick read if your home is older or in a special area.
Step five: lead work and repointing
Where the chimney meets the roof, a metal called lead is fitted to keep water out. Lead is shaped by hand to fit snugly around the base of the stack. This is one of the most important parts of the job, because most chimney leaks start here when the old lead fails.
The team will also finish the mortar joints neatly, a job known as repointing. Repointing means pressing fresh mortar into the joints between the bricks and smoothing it off, which both seals the stack against rain and gives it a tidy look.
Step six: the pot, the finish and clearing up
Near the end, the chimney pot is fitted or refitted on top, and any flue or cowl is put back. The team checks the whole stack over, cleans off the brickwork and makes sure everything is straight and sealed.
Finally the scaffold comes down, the skip is taken away and your garden or drive is swept clean. A good crew leaves the site as tidy as they found it. You can see the kind of neat result to aim for in this London chimney installation project.
How long does it take? A rough stage guide
Every chimney is different, but here is a rough idea of the stages and how long each one usually takes. Weather, height and access can all change these times.
| Stage | What happens | Rough time |
|---|---|---|
| Survey and quote | Builder checks the stack and sends a written price | 1 visit |
| Scaffold up | Safe access is built around the house | Half a day to 1 day |
| Take down old stack | Worn bricks removed by hand | Half a day to 1 day |
| New brickwork | Stack rebuilt with fresh brick and mortar | 1 to 2 days |
| Lead work and repointing | Base sealed with lead, joints finished | 1 day |
| Pot, finish and clear up | Pot fitted, site cleaned, scaffold down | Half a day, plus scaffold pickup |
Most straightforward rebuilds take a few working days on site, with the scaffold up for a little longer at each end. A taller or harder to reach stack takes more time.
A few tips for the day
Keep windows near the chimney shut while the work is on, as brick dust travels. Move cars off the drive if the team needs the space for a skip or scaffold. And do not worry about the noise of bricks being tapped into place, as that steady sound means the stack is going up straight.
Ready to plan your rebuild?
A chimney rebuild is a normal job for a skilled team, and knowing the steps takes away the worry. If you would like the stack checked and a clear written price, our roofing and chimney services cover London and the surrounding counties, with hand formed lead work and a neat, lasting finish.