Hi all, hoping for some advice on an ongoing chimney leak that’s proving hard to pin down.
Background
A couple of years ago I noticed water ingress around the face of our chimney stack. A roofer found the chimney pot and flaunching were cracked and replaced them. When that didn’t resolve the issue, new lead flashing was installed. That mostly helped, but there was still some water ingress on the north side, so the following summer Stormdry masonry cream was applied.
Since then it’s been fine in dry weather and over summer, but during winter, especially after prolonged heavy rain, water still gets in at one specific spot on the north side. The amount is small, but enough to soak the cement render covering the stack inside the loft. From there, the moisture transfers into the ridge board. I’m concerned that having the ridge board damp for several months each winter/spring will eventually lead to rot.
Questions
Any insight would be much appreciated, particularly from anyone who’s dealt with similar persistent leaks.
Thanks in advance.
After the last set of repairs in June 2024
Today - dry all around apart from water sitting inside the brick chase and running down the cement render
An inside view of the same spot, this was in 2024 before the stormdry. Still leaking today
The ridge board, embedded in the render and soaking wet
Frontal view of the chimney stack
Background
A couple of years ago I noticed water ingress around the face of our chimney stack. A roofer found the chimney pot and flaunching were cracked and replaced them. When that didn’t resolve the issue, new lead flashing was installed. That mostly helped, but there was still some water ingress on the north side, so the following summer Stormdry masonry cream was applied.
Since then it’s been fine in dry weather and over summer, but during winter, especially after prolonged heavy rain, water still gets in at one specific spot on the north side. The amount is small, but enough to soak the cement render covering the stack inside the loft. From there, the moisture transfers into the ridge board. I’m concerned that having the ridge board damp for several months each winter/spring will eventually lead to rot.
Questions
- Can I shorten or isolate the ridge board where it meets the chimney?
My thought was to interrupt the contact between the ridge board and the chimney to stop capillary transfer of moisture. As far as I understand, the ridge board shouldn’t need to be structurally fixed to the chimney itself. Would it be acceptable to cut it back slightly where it meets the cement render, or is that a bad idea? - Any thoughts on why it would still be leaking in one very specific area?
The roofer’s view was that the next escalation would be repointing the entire stack. The roof is around 75 years old and will need replacing in the not-too-distant future, so it might make more sense to do that work together. That said, I’m not convinced pointing is definitely the root cause.
The chimney stack is shared. Our neighbour hasn’t installed a chimney cowl, their flaunching is still cracked, and they still have the original lead flashing. They say they have no water ingress issues. Could water be entering on their side of the stack and tracking across to ours? If so, how would I go about confirming that?
Any insight would be much appreciated, particularly from anyone who’s dealt with similar persistent leaks.
Thanks in advance.
After the last set of repairs in June 2024
Today - dry all around apart from water sitting inside the brick chase and running down the cement render
An inside view of the same spot, this was in 2024 before the stormdry. Still leaking today
The ridge board, embedded in the render and soaking wet
Frontal view of the chimney stack
