Problems & Repairs
Smelling your own fire in a bedroom two floors up is not the same problem as a chimney that smells musty in summer. This one happens while the appliance is running, and it means combustion gases are finding a route out of the flue and into the house.
It deserves a proper look rather than an open window, because anything carrying smoke can carry carbon monoxide.
The main causes, in the order we check them
Nearly all of these come down to one of two things: a flue that is not gas tight, or a house pressure balance that is pulling gases out of the flue instead of letting them rise.
- Cracked parging or open mortar joints inside an unlined masonry flue
- A shared or adjacent flue in the same stack, common in terraces and tenements
- An unsealed disused fireplace opening in an upstairs room
- Negative pressure from extractor fans, a tumble dryer or a mechanical ventilation system
- A poorly sealed register plate or flue connection at the appliance
- Weak draw, so gases take any available secondary route
The pressure test you can do yourself
Light the fire as normal, then turn off every extractor fan in the house and close internal doors between the appliance and the room that smells. If the smell reduces markedly, the house is being depressurised and pulling gases through the structure. That is a ventilation problem with a ventilation solution.
If the smell is identical either way, the flue itself is leaking and no amount of airflow management will fix it.
Old stacks and shared flues
Older masonry stacks in this part of Scotland often contain several flues side by side, separated only by a single course of brick and a coat of parging. Over a century that parging cracks, and a flue running hot next to a cold unused one will happily push gases sideways.
In flats and terraces the neighbouring flue may not even be yours, which is worth knowing before spending money on your own appliance.
How the cause gets confirmed
A camera survey shows the internal condition of the flue, including cracked parging, open joints and breaches into adjacent flues. A smoke test is the other tool: the flue is filled with test smoke and the building is watched for where it emerges, which is the definitive answer for a leaking stack.
Once the route is known, the remedy follows from it. A leaking masonry flue is usually resolved by lining it, which turns a porous shaft into a sealed pipe. A pressure problem is resolved by adding air where the appliance needs it.
In the meantime
Fit or check a carbon monoxide alarm in the room where the smell is appearing as well as the room with the appliance, and use the stove sparingly until the cause is known. Smoke smell in an upstairs bedroom is worth acting on quickly rather than living with through a winter.
It is also worth blocking off nothing in the meantime. Sealing an upstairs fireplace opening with plastic or expanding foam while the cause is unknown simply moves the gases somewhere else and removes the ventilation the old stack relies on to stay dry. Leave the openings as they are until the flue has been surveyed, then seal or line them properly as part of the repair.
Frequently asked questions
Could it just be smoke on soft furnishings?
Possible, but easy to rule out. Residual smell is constant. A leak smell appears while the fire is lit and fades hours after it goes out, and it is usually stronger near a chimney breast or a blocked up fireplace.
Is it my neighbour's fire?
In a terrace or tenement it can be, especially where flues share a stack and the parging has failed. A smoke test tells you whether the smoke in your bedroom came from your flue or from next door.
Will lining the chimney fix it?
Where the cause is a leaking masonry flue, yes, because a continuous liner seals the whole route from appliance to terminal. It will not fix a house that is being depressurised by extract fans, which is why the diagnosis matters first.
Is this dangerous?
Treat it as a safety issue. Anything that lets smoke into a sleeping area can let carbon monoxide in as well. Fit an alarm, limit use of the appliance and get the flue checked promptly.
Smelling smoke where there is no fire?
We can sweep, camera survey and smoke test the flue to find the actual route the gases are taking. Send us the details and we will get it booked.