🐦 Roofing guide
What every homeowner should know about pots, cowls, capping unused chimneys, and dealing with nesting birds.
Most chimney questions we get aren’t about repointing or flashing — they’re about pots, cowls, and what to do about birds or wildlife that have taken up residence in an unused stack. Here’s the practical guide.
Chimney pots are usually clay, and while durable, they do crack over time, particularly on coastal properties where salt air accelerates weathering (see our coastal roofing guide). A cracked pot isn’t usually an emergency, but it’s worth replacing before a crack widens enough to let water track down into the stack itself.
If a pot is missing entirely — not uncommon after a storm — it should be replaced or the flue capped, since an open flue is both a water ingress point and, in older properties, occasionally how wildlife gets in.
Stop wind pushing smoke back down an active chimney — worth it if you get smoke issues on windy days with an open fire or log burner.
The most common type fitted — stop birds and wildlife entering the flue while still allowing it to draw and ventilate.
Reduce water ingress into an unused flue without fully sealing it, since a flue still needs some ventilation even when not in use.
If you’re getting a chimney worked on for any reason, it’s usually worth fitting a bird guard cowl at the same time if one isn’t already present — a small addition to the job that prevents a much more awkward problem later.
If a chimney is no longer used — the fireplace has been blocked up, or a gas fire replaced an open one — the flue still needs some airflow to prevent damp and condensation building up inside the stack, which can eventually show as staining on chimney breast walls.
The correct approach is a ventilated cap, not a solid seal. A vented cap keeps the flue closed to rain and wildlife while still allowing air movement, which is what actually prevents the damp problems people are usually trying to solve.
Jackdaws in particular are drawn to open chimney stacks and can build a nest surprisingly quickly — sometimes within days during spring. This is a genuine problem beyond noise and mess: a nest blocking a flue on an active chimney is a fire and carbon monoxide risk, and even on an unused chimney it can hold moisture against the stack.
What we do: once we’ve confirmed via inspection that a nest is inactive (nesting birds and their nests are protected under the Wildlife and Countryside Act while in use — removal has to wait until the nest is no longer active), we clear the flue and fit a bird guard cowl to prevent it recurring. If you suspect birds are actively nesting, don’t attempt to clear it yourself — get it inspected first.
Call us for a free survey and honest advice — no pressure to remove a chimney that’s perfectly sound.
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