How often should a chimney stack be checked?

Nobody sets a deadline for looking at the outside of a chimney, so the best schedule is a habit you will actually keep. Once a year is a sensible baseline, and the same check after any hard gale or spell of driving rain catches problems early. Choose a dry, bright day and walk far enough from the house to see the whole stack, from its base to the pots.

The stack sits in the most exposed spot on the roof. It is high, open to every side and takes wind and rain from all directions, so it ages faster than the tiles around it. Small faults such as a washed-out joint or a lifted corner of lead are cheap to put right and expensive to ignore. The habit costs nothing, and a pair of binoculars improves it a great deal.

Start at the top. Check that each pot sits upright and that the cap or cowl is in place. Look for a stack that appears to lean, or one with a visible crack running across it. Then work down the brickwork, noting any bricks with a crumbled surface, pointing that has gone dark and soft, white salt marks, or green growth that stays wet.

Finish at the roof. Is the lead along the sides and front lying flat against the stack, or has an edge curled away? Are there gaps, loose bits of cement or stains below the base? Take a few photographs each time. Comparing this year's pictures with last year's is the easiest way to see whether something is moving, and it gives a roofer something solid to work from. Our guide to a leaning chimney explains what to do if the stack is out of line.

The inside of the house tells you things the outside cannot. Look at the chimney breast in every room it passes through, and at the ceiling around it. A brown patch, peeling paint, blistered wallpaper or a damp smell are early signs of water. Up in the loft, given a torch and a boarded floor, look at the timbers and the brickwork around the stack for wet marks, tide lines or dripping.

Check again after rain. A fault that only shows after a downpour is easy to miss on a dry day. If you find a stain, mark its edge in pencil with the date, and see whether it grows. Our page on a damp chimney breast helps you decide whether the stain comes from the stack or from somewhere else.

Binoculars only go so far, so some moments call for a roofer to inspect the stack up close. These include after a major storm, before you buy a house, before a long winter away, and whenever any of the signs above appear. It also makes sense when scaffold is already up for other roof work, because access is the expensive part of looking at a high stack.

Checkatrade, in a table last updated September 2026, puts a typical roof inspection at about £260 and a drone survey at around £210, both plus VAT. Checkatrade's scaffolding guide (table last updated October 2026) gives around £660 a week for a chimney, which is why a visit from the roof ladder or from scaffold already in place is the sensible way to look. Each fault is photographed, and any work is quoted in writing as one total.

Some signs are urgent. A stack that leans, loose bricks or pots that move, a crack that has opened since your last look, or flashing that has torn away after a gale can all be dangerous below. Keep people away from the area under the stack and call a roofer. Never climb up to look.

Active water inside is the other urgent one. We prioritise leaks and make the roof safe first, then survey for the lasting repair. After storm damage, your insurer should hear before anyone else, and photographs and receipts are worth keeping. Our page on chimney storm damage sets out the order of things.

A chimney is easy to overlook at a viewing. A buyer's survey may only note that the stack was seen from the ground, and a stack that looks tidy from the street can have open joints or spent lead up close. If you are buying, ask for the stack to be looked at before you exchange, especially on an older house with tall stacks.

If you are selling, a roofer's note on the condition of the stack, with photographs, can head off a late price argument. Landlords gain from the same habit, because a tenant may not notice a stain in the loft until the ceiling below has taken on water. Whatever your position, the chimney repairs hub explains the work a stack may need, so you know what a note in a survey really means.