The most exposed
masonry on
your house.
A chimney gets weather on four sides and above. It fails before anything else on the roof, and when it does the water comes in somewhere that looks nothing like a chimney problem.
Four sides,
no shelter.
Every other wall on the house has something protecting it. A chimney stack stands clear of the roof with weather hitting it from all directions and driving down into it from above. It also goes through the biggest temperature swings on the building, because a flue that is in use gets hot and then cools.
That combination erodes mortar joints on a stack far faster than on the elevations below. It is normal for a chimney to need repointing when the walls beneath it are still perfectly sound, and it is why a stack is often the only masonry on a house that has been repointed twice.
The cement collar
at the very top.
The flaunching is the sloped mortar bed at the top of the stack that holds the pots in and sheds water off the top course. It is the single most exposed piece of mortar on the house and it is the first thing to crack.
Once it has cracked, water goes straight down inside the stack rather than off it. That is how you get damp staining on a chimney breast in a bedroom with no obvious external cause, and it is why people spend money on the inside of that wall repeatedly without success.
Where the stack
meets the roof.
The joint between a stack and the roof covering is closed with lead: a front apron, side soakers and stepped flashing, and a back gutter behind. It is a system, and it fails at the weakest part.
Common failures are lead that has been repaired with mortar fillets, which crack within a couple of winters, and cement rendering over the joint instead of proper lead. Both are cheap fixes that guarantee a return visit. Failed flashing produces damp at ceiling level near the chimney breast, usually only after driving rain from one direction.
What your report
probably said.
Typical wording includes the flaunching is cracked and requires renewal, the stack requires repointing, the lead flashings are showing signs of deterioration, and disused flues should be capped and ventilated.
Chimney repairs,
from pots to rebuilds.
Repointing the stack
Eroded joints are raked out and repointed in a mortar matched to the brick, softer than the brick so the joint weathers instead of the face. See repointing for the walls below.
Partial or full rebuilds
A stack that is leaning, cracked through or has loose brickwork at the top is taken down to sound masonry and rebuilt, reusing the original bricks where they are good enough.
Flaunching, pots and cowls
Cracked flaunching is renewed, broken pots replaced or reset, and disused flues fitted with ventilated caps.
Lead flashing and back gutters
Aprons, soakers, stepped flashings and back gutters are renewed in lead, dressed and fixed properly rather than patched with mortar. Leaks around the stack often turn out to be a roof repair at the junction.
How a chimney
repair job runs.
We start by looking at the stack, from the ground with a camera or from photos you send, and reading any survey wording. You receive a written fixed quote covering the access and every repair. Scaffold goes up, the work is done in one visit, and we send photographs of the finished stack, because it is the part of the house you will never see yourself. Where gutters, fascias or upper pointing also need attention, we price them for the same scaffold. See gutters, fascias and soffits.
Questions we get
asked most.
Get a written
price.
Monday to Saturday 9am to 8pm, Sunday 9am to 3pm. All London boroughs.
Message us on WhatsAppSend the paragraph from your report and we will price the work it describes.
Often needed
alongside this.
Areas we cover.
We take chimney stack repairs across all 32 London boroughs. Most of our work is in west London, in Shepherd's Bush, Hammersmith, Fulham, Kensington, Chiswick and White City, and in south west London, in Putney, Wandsworth and Wimbledon. We also work in south east London, in Greenwich, Blackheath and Lewisham.
If your property is outside these areas, call us anyway. We travel across London and will tell you honestly if a job is too far to price properly.