Why Does My Chimney Smell?

Plausible causes

• Creosote and soot deposits: these hold a smoky, sometimes tar-like odor that gets stronger when damp. See creosote buildup and cleaning.
• Moisture: water entering through the crown, cap, flashing, or masonry can wet the flue and deposits, and bring out a musty or damp smell. See flashing and roof leaks.
• Airflow reversing: house pressure from exhaust fans, a tight home, or a flue that is cold can pull air down the chimney into the room. An open or damaged damper can add to it.
• Animal or debris in the flue: something has entered the chimney. Removal is best handled by a wildlife professional.
• Other sources: a nearby appliance, mold, or odors from elsewhere in the house can be mistaken for a chimney smell.

Clues that help narrow it down

• Does it get worse in humid or rainy weather?
• Is it stronger near the fireplace or somewhere else?
• Does it appear when a fan or dryer runs?
• Was it there after the last cleaning, or did it begin recently?
• Do you see staining, rust, or dampness?

What an inspection does

The inspector checks the firebox, damper, flue, cap and crown, and the condition of deposits, and may use a camera. The aim is to identify what is feeding the odor, rather than masking it. Deodorizing products may reduce the smell for a while, but if moisture or deposits remain the odor can return. No product removes the odor in every home, so the source matters.

If you smell gas or burning

A gas smell, a smell of something burning, or any sign of carbon monoxide is a safety issue. Leave the house and call your gas utility or emergency services. Do not try to diagnose it yourself.

Questions to ask

• What is likely causing the smell, and what did you see?
• Is moisture a factor, and where is it entering?
• Could cleaning, a cap, or a damper change help?

Related pages

Chimney cleaning, chimney inspection, damper repair, Our Work.