Question answered
Chimney sweep or roofer: who fixes what?
The short answer
A chimney sweep looks after the flue inside the chimney: soot, blockages, nests and the condition of the lining. A roofer looks after the stack above the roof and where it meets the slope: pointing, flaunching, pots, flashings and the lead around it. If water comes in at the stack, you need a roofer. If smoke or fumes come back into the room, start with a sweep.
A chimney has an inside and an outside, and different trades look after each. Knowing which side your fault is on saves a wasted call-out.
Flue and stack are two different jobs
Think of the chimney as a pipe with a brick sleeve. The pipe is the flue, the passage the smoke goes up. The sleeve is the stack, the brickwork that rises through the roof, with its pot on top. A sweep works from inside the flue, using brushes and a camera. A roofer works from outside, on the brickwork and the roof junction.
The two meet at the top. A pot is part of the flue outlet and also part of the stack, so a broken one could be either trade's work, and a roofer usually fits it. It is the same with a flue lining: relining the inside is flue work, but the stack around it is still masonry.
Both trades should be able to tell you honestly when the fault is on the other side of the line, and that is a good test of whoever you call.
What a sweep deals with
Sweeping clears soot and tar that build up when a fire or stove is used, and it removes anything that has fallen or been built into the flue: bird nests, jackdaw sticks, loose mortar and the odd dead bird. A sweep can also run a smoke test or camera along the flue to find cracks, gaps in the lining or blockages higher up.
Call a sweep when smoke comes into the room, when the fire draws badly, when you are about to use a fireplace after a long time, or when you have just had a stove fitted. Birds' nests are a common cause of a chimney that suddenly will not draw.
A sweep can tell you the flue needs relining, and may refer you to a flue specialist, but they do not usually repair the stack outside.
What a roofer deals with
A roofer looks at everything you can see from the roof. That is the pointing between the bricks, the flaunching round the pot, the render if there is any, the lead flashing at the base of the brickwork, and the back gutter behind a wide stack. Those are the places rain gets in, and a stain that spreads on an upstairs wall after a storm is a roofer's problem more often than a sweep's.
A roofer can also replace a broken pot (see replacing a chimney pot), fit a cowl or cap, and repair a leaning or crumbling stack. Cowls, caps and guards each suit different flues, and we cover the choice on our chimney repairs page.
A roofer cannot inspect a stack safely from a ladder, so the checking happens off a scaffold or a tower. We photograph what we find, so you see the pointing, the bed and the lead for yourself.
Symptoms and who to call
A few signs sort out who to ring. Damp patches on the breast or ceiling after rain point to the stack, so a roofer. Soot or smoke in the room, or a fire that will not draw, point to the flue, so a sweep. A musty smell from a closed-up fireplace often points to damp air in a sealed flue, which may need a roofer to fit a ventilated cap, a point we explain when we discuss capping a disused chimney.
Loose bricks or pieces of pot on the ground, a stack that leans, or a crack running up the brickwork are roofer or builder jobs. Rubble in the grate usually means the flue lining, the pot or the top of the stack is breaking up, and it needs a look from both the inside and the outside.
If you cannot tell, a roofer's survey from the outside usually settles it, and a sweep then checks the inside if it has to.
When both are needed and how to sequence them
Some faults need both. A stack that is leaking and a flue that is blocked with nests is a common pair. The sweep clears the flue first, so a roofer is not working over loose debris and can see the true state of the brickwork. Then the roofer repairs the stack and, if wanted, caps or recovers the pot.
On a shared stack, the neighbour's flue is part of the picture, and agreeing access with them early saves delay; who pays for a shared chimney stack covers it.
The survey leads to a written quote that is one total. Ask any contractor what the figure holds for scaffolding and VAT, since chimney work is often held up by access and not by the repair itself. A job that needs a sweep first is easy to fold into the same week.
Sweep or roofer: two more questions
Should a stack be swept before a roofer repairs it?
When the flue is in use or has not been cleaned for years, yes. Sweeping first clears soot, nests and loose mortar so the roofer can see the inside of the pot and judge the brickwork. For a flue that is disused and capped, it is often unnecessary.
Who checks a flue liner?
A sweep or flue specialist checks the lining from inside, often with a camera. A roofer checks the stack and the pot at the top. If the lining is cracked or missing, the relining is flue work, and the roofer deals with the masonry around it.
Tell us about your roof
Describe what is happening and we will call you back to arrange a visit.
- Photographs of what we find
- A written quote with one total price
- Or call 01903 299063
10-year workmanship guarantee, in writing.