Flaunching — the sloped mortar fillet that holds chimney pots in place at the top of the stack — is one of those details that goes unnoticed until it fails, at which point it becomes a fairly direct route for water into the chimney. In Warmley, where stacks vary widely in age, we regularly find flaunching that's cracked, crumbled or come away entirely, often well before homeowners notice anything is wrong from the ground, since it sits above the sightline of anyone standing in the garden or street below. Because it's so rarely inspected directly, flaunching failure is one of the more common surprises we find during a chimney survey carried out for an entirely different reason.
Because flaunching sits at the very top of the chimney, it takes the full force of weather with no protection at all, and cement-based flaunching in particular can crack over time due to the same expansion and contraction that affects brickwork lower down the stack. Once it's cracked, rainwater can track straight down inside the flue or around the outside of the pot into the stack itself, often for a considerable time before it becomes noticeable as damp indoors.
Chimney pots themselves are also vulnerable at this height — cracking from frost, chipping from debris, or simply working loose if the flaunching holding them has failed. A loose pot on a stack is a genuine hazard, particularly in high winds, and needs addressing promptly rather than left until it becomes a bigger problem, both for the safety of anyone below and for the state of the stack it's sitting on. Wind exposure plays a significant role here too, since a pot on the windward side of a stack often shows far more wear than one facing away from the prevailing weather.
Repairing flaunching properly means removing the failed material and rebuilding it with a mix appropriate to the pots and stack, angled correctly to shed water away rather than let it pool. Where pots have cracked or are the wrong size for the flue, replacement is usually more sensible than attempting a patch repair that won't hold up long term, particularly given how exposed this part of the chimney is to every kind of weather the roof faces.
It's worth having flaunching and pots checked together with the general condition of the flue, particularly on properties with more than one chimney pot, since it's common for one to be in noticeably worse condition than the others depending on which way it faces and how much shelter it gets from surrounding structure. Where one pot needs attention, it's sensible to have the others checked at the same visit, since access is already arranged and the cost of doing so is minimal by comparison.
If your chimney pots look loose or the flaunching around them is visibly cracked, it's worth having it checked before wet weather gets inside the stack. Brunel Roofing Bristol carries out pot and flaunching repairs across Warmley, with free quotes and inspections available and all work backed by our 15-year guarantee.
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