What are the Most Common Chimney Problems?

Chimney problems can range from a minor inconvenience to a major expense, or even a serious health concern. A chimney is usually a vertical structure used to conduct gases or smoke from a stove, fireplace, boiler, or furnace into the outside environment. Whether or not a chimney is used to vent gas from a wood or gas burning stove, it is important to identify, treat, and prevent chimney problems.

One of the most common chimney problems is the build-up of creosote on the inner walls of the chimney. Creosote is a sticky, odorous substance that forms when the gases from wood burning combine and cool in the chimney. Creosote deposits are particularly common with airtight wood burning stoves and fireplaces, which produce cooler temperatures in the chimney. If not prevented or treated, creosote builds upon itself and causes chimney narrowing and various other chimney problems, including unpleasant smells, corrosion of the chimney walls, and chimney fires.

There are several ways to deal with creosote, such as switching to gas or oil heating. If that is not practical or desirable, it is important to keep the chimney at a temperature of above 250 degrees Fahrenheit (121 degrees Celsius) and clean the chimney thoroughly at least once a year. Using dry wood can also help prevent creosote build-up, as it creates less steam and is less likely to cool the chimney temperature. Modern wood burning stoves often trap gases and burn them before they reach the chimney, thus preventing creosote from forming. The construction of the stove can also reduce the amount of creosote accumulation, so it is helpful to discuss options for chimney size, placement, liners, flue size, and other variables with a stove dealer before installing a stove.

Poor or outdated construction can also lead to several other chimney problems. Oversized and unlined chimneys often have cool temperatures and, as a result, poor drafts. This means that, as the gases cool, instead of traveling out of the chimney and into the atmosphere, they condense and remain trapped in the structure.

The build-up of water vapor can lead to corrosion in the chimney as well as in the household, if the vapor travels back indoors. Gases can also accumulate and leak back into the home, causing possible health problems. Construction problems can often be solved with a modern chimney liner, but sometimes a new chimney may be needed.

A blocked chimney can also cause smoke or other dangerous by-products of fire burning to leak back into the house. Bird nests are a common culprit and can be ousted simply by a thorough, routine cleaning. Creosote build-up and loose bricks or chimney material can also cause smoke to not draw up the chimney properly and billow back into the house. Cleaning, re-lining, and repairing the chimney should fix these chimney problems