Cracked Chimney Pot: Replace or Remove?

A chimney pot is the clay or concrete pipe on top of the stack. It raises the flue's outlet clear of the brickwork, helps the smoke escape and gives the flue a rain-shedding top. It sits in a bed of mortar called flaunching, which slopes away from the pot so that water runs off the stack.

Pots crack for a few reasons. Frost gets into small cracks and widens them, heat and cold cycles in a flue in use stress the clay, and a failing flaunching lets water collect around the base of the pot, where it can freeze. A pot may also be fine but seated in a flaunching that has cracked right through, so the pot is loose without being broken.

Standing in the garden you can often spot leaning, large chunks missing or a ring of cracked mortar around the foot. Look at it with binoculars and photograph what you see. Our guide to chimney flaunching repair explains the bed a pot sits in and how it is renewed.

Replace a cracked pot where the flue is used for a fire, stove or boiler. The pot is part of the way the flue works, and a cracked one can let in rain, drop clay into the flue and, in time, cause a blockage. A roofer lifts the old pot, cleans the top of the stack, beds a new one on fresh mortar and forms new flaunching around its base.

The new pot should match the flue size and the look of the neighbouring pots, especially on a terrace or semi where the stack is shared. Many standard sizes and clay colours are made, and a roofer can usually order one to match. Where the old pots are unusual, a close match or a reclaimed pot may be needed.

Check that the roofer also looks at the top courses of brick and the lead around the stack while they are up there. Fixing a pot on a stack with crumbling mortar underneath only moves the problem down a level. Our chimney cowl types guide shows the toppings that can be added to a replacement pot, and our chimney repairs page covers the wider work.

If a fireplace is closed off and the flue will never be used again, there is no reason to keep a pot that is crumbling. The roofer can take it off, form a sloping mortar top and fit a cap. A cap that lets air through keeps the flue ventilated, which stops damp building up inside the chimney breast. Checkatrade's April 2026 chimney repair guide gives £180 to £520 for a cap as a typical UK range.

A flue that is simply sealed with no airflow can cause damp patches in the room below. That is why a vented cap, or a vent low in the breast, is normal practice. Our guide to capping a disused chimney goes through the details.

On a shared stack, a pot or cap may affect the neighbouring house, because the flues are separate but the brickwork is joined. Talk to the neighbour before any work starts. A listed house or one in a conservation area needs a call to the council's planning team before pots come off, since they can be part of the street's character.

A pot weighs a great deal, and it sits at the top of a stack that gets the worst of the wind. A pot that rocks can drop, take flaunching with it or land on the roof, the path or the garden. A storm can bring a loose one down in a moment, and so the repair is more a safety job than a cosmetic one.

If you notice a pot leaning or a piece missing, keep people and cars away from the area beneath it and photograph the stack from a safe distance. Do not climb up yourself. We can make the stack safe first, by removing a dangerous pot or securing it, and then replace or cap it once the survey is done.

Photos help for any insurance claim after a storm, and receipts and dates matter as well. What a claim can include depends on the policy wording, so read it or ask your insurer. To get a quote, send us a picture taken from the lawn or path, say whether the flue is still in use and whether the house stands alone, in a semi or in a terrace. We will plan the access first.