Are Clogged Wood-Burning Stoves Dangerous?

Some Basics

• Since a wood-burning stove will contain a fire, it must be able to take in oxygen, which is required to keep the fire burning, and it must also be able to dispose of the product of that fire -- the smoke. For both of these tasks, the stove relies on the chimney and the pipes within it.

How Clogs Happen

• Gases contained within the smoke from the wood stove pass up the chimney and cool. As they cool, they liquefy and eventually harden on the inside of the chimeny or stove pipe. This forms something called creosote, and it must be swept out of the chimeny on a regular basis to prevent it from blocking off the chimney.

Fire Danger

• One of the most obvious and most common problems with a clogged stove or chimney is that the clogs themselves can catch fire. Creosote alone can reignite in the chimney, which is not meant to contain a fire, and can then spread out to the rest of the house. Additionally, if the levels of creosote get too high, this can begin to trap other small elements that should be allowed to pass out the top of the chimney, such as small pieces of paper or wood. These small pieces build up in the chimney, ignite and start a chimney fire.

Air Danger

• Although it is less obvious than a fire, carbon monoxide and smoke buildup present just as great a danger. As long as a fire continues to burn in the stove, the smoke and gas from the fire will have to go somewhere. If they are not allowed to pass freely up the chimney and out of the house where they belong, they may build up and find their way into the house. This can create a lung irritant at best, and can create deadly levels of carbon monoxide in the worst cases.