What is the primary cause of chimney fires?

The primary cause of chimney fires is creosote buildup. Creosote is a flammable substance that accumulates within the chimney flue as a result of incomplete combustion of wood or other fuels. When wood burns, it releases gases and particulates, and as they cool, they can condense inside the chimney. Over time, this accumulation of creosote can become thick and sticky, creating a highly flammable layer.

When creosote ignites, it can cause a rapid increase in temperature within the chimney, leading to a chimney fire. These fires can be extremely dangerous, potentially spreading beyond the chimney and into the home's structure. Regular chimney cleaning and inspections are essential to remove creosote buildup and reduce the risk of chimney fires.

Other factors, such as blockages in the chimney from caps or bird nests, or issues with the flue liner, can contribute to chimney problems, but the fundamental cause of chimney fires is primarily due to the buildup of creosote being ignited during use.