Roofer or Chimney Sweep: Who Do You Call?

A chimney has two sides. Inside is the flue, the passage that carries smoke and fumes from the fire to the open air. Outside is the stack, the brick and mortar that rise through the roof, with a pot on top. A sweep works on the first. A roofer works on the second.

What is a sweep's job?

A sweep cleans the flue of soot and debris, clears blockages such as bird nests and fallen mortar, and can tell you whether the flue draws properly. If smoke comes back into the room, the fire burns poorly or you smell soot, those are sweep problems. A sweep also sees the inside of the stack from below and may spot damage that the roofer will then repair. Each trade often spots what the other cannot reach, which is why they pass work to one another.

The sweep does not repoint the stack, relay the flaunching or renew lead, and a good sweep will tell you as much. If a sweep's visit turns up a cracked pot or crumbling brickwork, that is the point at which a roofer is the next call. We do not sweep flues, and when a sweep is the right first step we tell you so.

The roofer's side starts where the chimney leaves the roof. Water is the common thread. Rain that gets in around the stack runs down inside the chimney breast and shows up as damp, stains and peeling paper on a bedroom or landing wall.

What does a roofer repair on a chimney?

The lead sheet that bridges the join between brickwork and roof, the flaunching that holds the pot, the pointing between the bricks, loose or frost-damaged brick in the upper courses, the pot itself, cowls and caps, and the slates or tiles that meet the stack. We also see the whole roof around it, so a failed valley or slipped slate beside a chimney is dealt with in the same visit.

Repointing a chimney runs from £450 to £1,200 as a typical UK range (MyJobQuote, Oct 2026). Work at height needs access, and for a tall stack that means scaffold or a tower, which adds to the bill and the lead time. For the full list of what roofers cover, read do roofers repair chimneys.

Your symptoms usually tell you who to ring.

Which symptoms mean a sweep and which a roofer?

Sweep: smoke coming back into the room, soot falling into the fireplace, a smell of soot when the wind blows, a fire that will not draw, birds or debris dropping into the grate. Roofer: a stain on the wall beside the breast, a pot at an angle, crumbling mortar or white salts on the brick, a gap round the lead, a stack with a lean.

Damp on the breast can look like a flue problem and often is a roof problem. Rain entering through the stack top, or the flashing, is a common route, and our answer on damp on a chimney breast covers the causes. If you cannot tell, a survey from the roof shows us whether the water is entering outside, and the pictures we show you settle the question. A damp patch that grows after rain and shrinks in dry weather points to the roof side, not the flue.

If a pot looks loose, keep clear of it until a roofer has made it safe. Note which room the symptom shows in, because that points us to the right side of the stack.

Some chimney jobs take two visits from two trades, and the order helps.

Who goes first?

If the flue is blocked, the sweep goes first, because a nest or a fall of mortar in the flue tells the roofer what is above it. If water is the problem, the roofer goes first, because rain in the flue wets soot and turns a simple sweep into a messy one. When a cowl is fitted to stop birds nesting, the roofer fits it after the sweep has cleared the flue, so nothing is sealed in.

A pot replacement is the classic shared job. We replace the pot and relay the flaunching, and the sweep checks that the flue behind it runs clear. Our answer on replacing a chimney pot goes through the steps.

For all stack work see chimney repairs. Describe the symptom when you ring 01823 297042, and we will say whether the first visit should come from us or from a sweep, so you book the right trade once.