All About chimney soot

Questions we get asked frequently about soot

Where does it come from?

Fire creates different gasses when it burns. These gases are lighter than air and as they go up the chimney and soot builds up on the inside walls. This includes a flammable substance called creosote. Soot is released into the air as very small particles or as liquid droplets. As this goes through the chimney, it sticks and builds up on the inside. This can clog and even block the chimney.

What is soot?

Soot is a fine black or brown powder that can be slightly sticky and is a product of incomplete combustion. Soot contains a lot of carbon. Since soot is sticky, it tends to stick to exhaust pipes and chimneys where the combustion occurs. Soot is composed of a variety of chemicals and its exact composition depends strongly on what is being burned.

Why is soot a problem?

In places such as chimneys, the formation of soot can result in clogged chimneys. If soot is allowed to build up in the chimney for too long, it can cause smoke to back up into the room or even cause a fire. Soot is a also pollutant and causes environmental and health issues.

Can soot cause health issues?

Yes. Soot can be harmful to humans when inhaled. The incomplete combustion necessary to produce soot results in the formation of dioxins and other toxic compounds. The small size of particulate matter allows it to easily enter the lungs and bloodstream. This can cause serious problems including heart attacks, bronchitis, aggravated asthma, strokes, and even premature death.

How often should a chimney be cleaned?

You should clean it at least once a year. Definitely needs to be done if you have not used your chimney for a while. If a chimney is used a lot, it might be necessary to sweep it more often. A professional will be able to advise you of the best cleaning schedule for your chimney.

What if I have a gas fireplace?

Not as often but yes. Blockages in chimneys connected to gas fires can lead to a build-up of carbon monoxide and other harmful gases. A professional will be able to advise you of the best cleaning schedule for your chimneys.