Why Does My Chimney or Wood Burner Smell Strongly of Tar or Creosote?
For a strong tarry, smoky or creosote-like smell from a stove, fireplace or chimney, especially when the appliance is cold or during damp weather.
What this usually means
A strong tar/creosote smell can indicate deposits in the chimney or flue, often associated with wet fuel, low-temperature burning or insufficient sweeping. Creosote is combustible, so persistent heavy deposits are a fire risk rather than just an odour problem. Stop using the appliance if you suspect heavy tar build-up, and arrange professional sweeping and inspection before relighting.
What may be causing this
Creosote/tar deposits have accumulated in the flue
Clues: The smell is strong and the chimney has been used with wood or sweeping is overdue.
What to do: Arrange professional sweeping and inspection.
Fuel has been too wet or the fire has been run too cool
Clues: There is black/tarry residue and a history of smoky low-temperature burning.
What to do: Use approved dry fuel and correct burn settings after the flue is made safe.
Damp weather or reverse airflow is bringing chimney odours indoors
Clues: The smell is strongest when the stove is cold and changes with weather/ventilation.
What to do: Have chimney ventilation, draw and termination assessed if persistent.
How to check what is happening
Assume deposits may be significant until inspected.
Creosote accumulation is likely.
Airflow reversal may be carrying chimney odours into the room.
Can you fix this yourself?
Do not scrape or burn off suspected heavy creosote yourself. A competent sweep can assess deposit type, chimney condition and safe cleaning.
- Service/sweeping records
- Camera for accessible visible deposits
What you can safely try
- 1
Stop use if heavy deposits are suspected
Do not try to 'burn the chimney clean'.
- 2
Book a professional sweep
Have the chimney cleaned and assessed.
- 3
Review fuel quality
Use dry, approved fuel once the system is safe.
- 4
Review burn practice
Avoid prolonged cool, smoky combustion.
Call a hetas-approved chimney sweep / stove technician if…
- There is a roaring sound, sparks/flames from the chimney or suspected chimney fire.
- A CO alarm activates or smoke enters the room.
- Heavy shiny/tarry deposits are visible or sweeping is substantially overdue.
Get the right hetas-approved chimney sweep / stove technician.
We already know this problem maps primarily to a hetas-approved chimney sweep / stove technician. Choose the closest type of work, add your postcode and continue in the form.
Sources used for this guide
We prefer primary UK guidance, regulators and manufacturers for technical and safety-sensitive claims.
- Burn BetterHETAS
- Wood-burning stove guidanceHETAS
Last reviewed: 5 September 2026. Home Manual updates review dates only when the substance of a guide is checked or changed.