In Old Swan, L13, many homes are inter-war semis with a single chimney stack straddling the ridge and shared with the house next door. That stack carries flues for both homes, so a leak or a cracked top can affect both. We inspect the stack, explain the cause with photos and quote in writing, and we are happy to work with both neighbours together.
Understanding the shared ridge stack
On a typical semi, the stack sits on the line where the two houses join, rising through the roof at the ridge. It may hold two, four or more pots. Because it is at the highest point of the roof, it gets wind and rain from every direction. The parts that fail most often are:
- The flaunching on top, which cracks and lets water into the stack.
- The lead where the stack meets the roof on each slope.
- The pointing on the windward face.
- The pots themselves, which can crack or loosen.
Each of these is fixable, and catching them early keeps the repair modest. If you are not sure which applies, our chimney leak repair page explains how we track down the cause.
Working out who does what
A shared stack raises practical questions. In most cases the owners share the cost of work on the shared masonry, and each owner looks after their own flues and pots. It is worth checking your deeds, and it is always worth speaking to your neighbour early. Repairing just one half of the top often does not stop water getting into the stack, so coordinated work is usually best value for both.
If your neighbour does not want to take part, we will tell you honestly what can be done from your side and whether it is likely to work. For removal or any alteration that affects their flue, their agreement is needed and the Party Wall etc. Act 1996 may apply; our stack removal page covers this.
Repairs on Old Swan stacks
New flaunching and pots
Cracked flaunching is broken out and replaced, and loose pots are rebedded or swapped for new ones. Disused flues can be capped with a vented cap. See our page on chimney pots, cowls and caps for the choices.
Lead on both slopes
Because the stack crosses the ridge, the lead runs down both slopes. We replace tired or patched lead with new lead flashing dressed to the roof covering.
Pointing
Worn joints are raked out and refilled. Often only the exposed faces need it.
If one half of a shared stack has already been removed by a neighbour in the past, the half that remains may need extra checks for stability. Let us know if you think this applies.
Districts we cover around Old Swan
We work across West Derby and Wavertree, where similar semis are common. For the full picture, visit our page on chimney repair throughout Liverpool, or see how we approach shared and single chimney repairs in other parts of the city.
Shared chimney trouble in Old Swan?
Call 07777 659786. Let us know if the stack is shared and what you can see, and we will call back.
Frequently asked questions
Damp is on both sides of our party wall. Is it the same leak?
Quite possibly. A shared ridge stack can let water into both halves if the flaunching or lead on top has failed. Comparing notes with next door helps, and an inspection will show where the water is getting in.
Can scaffold go on our side only?
For many jobs on a ridge stack, scaffold can be erected from one property, although reaching the far side can be harder. We plan access after inspection and will explain whether your neighbour’s garden or drive would be needed.
Our gas fire uses the flue. Does that change anything?
It means any cowl or terminal must suit the appliance. We will ask about it and fit something appropriate, and if anything at the top looks unsafe we will recommend a Gas Safe registered engineer checks the flue and appliance.
What is flaunching and why does it crack?
Flaunching is the sloped mortar collar on top of the stack that holds the pots and throws water off. Being flat-ish and exposed, it bears the brunt of frost and sun, and in time it cracks and lets water into the stack. Renewing it is a common repair.