Roofs almost never leak in the middle. They leak where the roof meets something else: a chimney stack, a wall, a valley. Those junctions are where the skill is, and where cheap work shows up fastest.
Specialist work to keep the weather out where roofs meet walls, stacks and valleys.
Why chimneys cause so many leaks
A chimney stack sits in the middle of a roof slope and interrupts the flow of water down it. Everything has to be detailed to send that water back out onto the tiles rather than into the roof, and there are several places for that to go wrong.
The mortar joints in the brickwork weather and open up. The flaunching on top, which is the mortar the pots sit in, cracks and lets water straight down the stack. The lead flashing where the stack meets the roof lifts, splits or was never dressed in properly to begin with. Any one of those will show up inside as a damp patch on a bedroom ceiling.
Leadwork done properly
Lead is still the right material for these junctions because it can be dressed to fit exactly what is there and it lasts for decades. What matters is that it is the right code of lead for the job, cut to sensible lengths so it can move without splitting, and properly chased into the brickwork rather than smeared over with mastic.
We see a lot of failed flashing that was fitted with sealant instead of being let into the joint. It looks fine for a year or two and then it lets go. Done properly, leadwork should outlast the covering around it.
Stepped flashing where a stack or wall meets a sloping roof
Front aprons and back gutters to chimney stacks
Lined valleys between two roof slopes
Abutment flashing where a roof meets a vertical wall
Soakers and cover flashing to roof windows
Repointing and rebuilds
Where the mortar joints have eroded but the stack itself is sound, repointing is the fix: rake out the perished mortar and repoint in a mix suited to the brick. On older, softer brickwork that means using a mix that is not harder than the brick, otherwise the brick face spalls off instead of the mortar taking the wear.
If the stack has moved, the brickwork has failed or it has been repaired badly too many times, a partial or full rebuild is the honest answer. We will tell you which of those you are looking at after we have seen it.
Good to know
Chimneys & leadwork questions
My chimney isn't used any more. Do I still need to maintain it?
Yes, if it's still standing it still needs to keep water out. An unused stack with cracked flaunching and open joints will let water into the roof and the wall below just as readily as a working one. If you never intend to use it, removing it back below roof level and tiling over is sometimes the more sensible long-term option.
Can you repair just the flashing rather than the whole chimney?
Often, yes. If the brickwork and flaunching are sound and it's only the lead that has failed, replacing the flashing on its own is a straightforward job and we'll price it that way.
Do you use lead or a cheaper alternative?
We use lead for these details. There are substitute materials available and they have their place, but for chimney and abutment work lead dresses to the shape properly and lasts, which is what you're paying for.
Other services
What else we do
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New Roofs & Re-Roofing
A new roof is one of the biggest investments you'll make in your home. We install new roofs and carry out full re-roofs across Cheshire and the surrounding areas, using high-quality materials and expert craftsmanship so yours is built to last.
