The mortar fillet shaped around the base of a chimney pot, known as flaunching, rarely gets a second thought until it cracks, at which point it becomes one of the more common sources of leaks and pot instability on chimneys across Bishopston.
Flaunching serves two purposes: it holds the pot firmly upright in position, and it's shaped to shed rainwater away from the join between pot and brickwork rather than letting it collect there. Sitting fully exposed at the very top of the stack, with no roof covering to shelter it, it faces more direct weathering than almost anything else on the property, and cracking over time is close to inevitable given enough years of frost and rain.
Once cracks appear, water collects in them instead of running off, and each freeze-thaw cycle through winter widens the crack a little further, until sections eventually break away and the pot loses some of its support. A pot that's lost its flaunching can start to lean, which is often the first visible sign from ground level that something's wrong at the top of the stack, even before any leak becomes apparent indoors.
Repairing cracked flaunching properly means removing the damaged material rather than patching over the cracks, since new mortar applied over an already-failed base tends to crack again at the join within a short time. The pots are reset securely and new flaunching formed and finished to shed water correctly, restoring both stability and weatherproofing at the top of the stack.
Sound flaunching also protects the pot's own lifespan, not just the brickwork beneath it. A pot held securely and kept dry at its base tends to last considerably longer than one sitting in cracked, water-retaining flaunching, so addressing flaunching promptly is as much about protecting the pot as it is about stopping leaks further down the stack. Flaunching problems often first come to light straight after a storm, when high winds finish off cracking that had already been developing quietly for years. If a pot looks slightly different, more tilted or less secure, after a spell of bad weather, it's a reasonable prompt to have the flaunching checked sooner rather than waiting for the next scheduled roof check. A quick visual check for cracking around the base of each pot, done safely from a distance with binoculars or from an upstairs window, is a reasonable habit to get into once or twice a year, particularly heading into the wetter autumn and winter months when the consequences of a crack left unaddressed tend to worsen fastest. Left unrepaired over successive winters, what starts as a fine hairline crack can widen considerably, so there is real value in dealing with it while the fix remains a small, contained job rather than a larger one.
Because flaunching sits out of easy view, it's worth including as a specific check whenever a chimney inspection is carried out, rather than assuming it's fine simply because there's no obvious leak yet. We check flaunching condition as standard during our free inspections across Bishopston.
Get a Free Quote for Chimney Repairs in Bishopston
Every chimney is different — the fastest way to get an accurate answer is a quick chat with our team.