The very top of a chimney stack — the pots and the flaunching that holds them in place — takes more weather punishment than almost any other part of a property's roof, and in Westbury-on-Trym, where many stacks have been standing since Victorian or Edwardian times, it's an area we're regularly asked to repair. Flaunching is the sloped mortar fillet around the base of the pots, and once it cracks, it stops doing its job of shedding water away from the stack effectively. Because it sits so far above eye level, this is an area many homeowners never think to check until a leak or a loose pot forces the issue.
Cracked flaunching is often caused by the same freeze-thaw cycles that damage brickwork lower down, along with ordinary ageing of the cement mix over decades of exposure at the highest, most exposed point of the roof. Once cracked, it allows water to track down inside the flue or around the outside of the pot into the stack itself, a problem that's easy to miss from ground level until damp starts appearing inside the property, sometimes well after the initial crack developed.
Chimney pots on older properties can also crack, chip, or work loose over time, and on period stacks it's worth checking that pots are the correct size and type for the flue rather than simply replacing like for like without inspection. A loose pot at that height is a genuine safety concern, particularly during storms, and shouldn't be left once it's been noticed, both for the wellbeing of anyone below and for the state of the flaunching supporting it. On some of the more ornate period stacks in this area, pots also carry a decorative role, so replacements are chosen with an eye to keeping the roofline looking consistent, not just to functional performance.
Repairing flaunching properly means removing the failed material entirely and rebuilding it with a correctly angled mix that sheds water rather than letting it collect around the base of the pots. Where pots themselves are damaged, replacement is usually the more sensible option compared with attempting to patch cracked or chipped clay, which rarely holds up for long once it's already compromised.
On properties with multiple flues, it's common to find pots in noticeably different states of repair depending on their exposure and whether they're still in regular use, so a proper survey of the whole stack rather than just the most obviously damaged pot tends to give a more accurate and complete picture of what work is actually needed. This kind of comprehensive check tends to be far more cost-effective than repeat call-outs for individual pots as each one eventually fails in turn.
If the pots or flaunching on your chimney in Westbury-on-Trym are looking worn, it's worth having them checked before winter weather finds its way inside the stack. Brunel Roofing Bristol offers free inspections across the area, with pot and flaunching repairs covered by our standard 15-year guarantee.
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