New Jersey Home Inspectors Should Identify Creosote Build Up

Home Inspector with lookSmart Home Inspections, LLC 24GI00058700

New Jersey home inspectors should be aware of creosote and why it is a safety hazard in homes. Creosote is the result of combustion that is not complete. As wood is burned the smoke leaves the fireplace and it condenses inside the chimney or the vent pipes.  Particles of non-burned compounds are carried up into the chimney or vent pipes in the form of smoke. This process forms the basis for creosote buildup.

Creosote is a very flammable sticky tar like substance that can burn at very high temperatures. Creosote is also carcinogenic (can cause cancer in humans) in its unburned state. Creosote must be cleaned with care and carefully removed.

Creosote buildup typically originates from a couple of causes.  The burning of unseasoned firewood can contribute to the buildup. The burning of unseasoned firewood produces a lot of smoke. The more smoke produced by the burning process the more creosote that is produced as well.

Another thing that creates creosote is burning wood at too low a temperature. Burning wood at a low temperature creates incomplete combustion resulting in harmful pollutants such as the build p of creosote. Low temperature burning will produce more condensation to form on the interior of the chimney and allow the products of combustion to adhere to the inner walls of the chimney. The proper temperature to burn wood in a fireplace is between 600 and 700 degrees. This range allows for more complete combustion which means that the wood burns more cleanly and will produce lower harmful emissions resulting is lower creosote buildup.

Another important component of proper burning of wood is to make sure the fire has the proper volume of fresh air. A fire that is deprived of oxygen will be low burning and create conditions that will build up creosote. Make sure your fire has ample oxygen and burns hot.

It must be understood that the complete prevention of creosote buildup is not possible event with the best care and burning.  Creosote buildup happens in three distinct stages. It is important for home inspectors in New Jersey to understand the three different stages to understand the risks associated with each stage.

Stage 1 Creosote buildup: This first stage is unavoidable. Stage one happens even with great care and high heat burning. State one is similar to a dust like sooty coating on the interior walls of the chimney or vent. At this stage the buildup is not unsafe however it should still be removed.

Stage 2 Creosote buildup: This stage is much more significant in terms of a safety concern. At this stage the creosote gives the appearance of flaky tar chunks.  It is at this stage that the buildup can restrict the chimney liner or venting. This stage is also significantly more difficult to remove. A much stiffer brush and scrapers will be required to remove the build up from the interior of the chimney or venting.

Stage 3 Creosote: This is the most unsafe stage of creosote buildup. Creosote at this stage will appear like a thick tar like coating on the interior of the chimney. This stage of buildup can cause a fire at even lower temperatures. Chemical treatment or a rotary chain whip will most likely be required to remove the build up at this stage. This is why chimneys should be cleaned often.

The National Fire Protection Association has a recommendation that chimneys, vents and fireplaces be cleaned yearly. A professional and reputable chimney sweep should perform the work. The frequency of cleaning can depend on several factors. The most important being how often does someone use their fireplace. If you use your fireplace on a regular basis which is often referred to as three times per month then you should have the chimney and fireplaces cleaned every year. Along with a cleaning an inspection should also be performed in order to determine if the condition of the fireplace and liner are still sound and safe.

It is important for NJ Home Inspectors to understand the signs of creosote buildup. Look for a dark black or brown tar like substance on the interior of the fireplace and chimney. Creosote is shiny and tar like. It can appear as a coating or in clumps or a hard crusty build up. Creosote also has a strong odor. the odor is unpleasant and can be identified when then fireplace is in operation. A creosote buildup can block the flue which can make fire building difficult. If fire making or starting is visible the flue may be blocked or partially blocked by creosote. Creosote buildup can also reduce efficiency. If your fires are not burning as hot as usually you may have a creosote problem.

Although New Jersey Home inspectors do not inspect chimney to the extent of a Level II chimney inspection they should still understand the importance of identifying creosote buildup and helping their clients to understand the importance of its removal. NJ Home inspectors should educate their clients about the harmful effects of creosote and help them to identify the material. The more education that a home inspector in NJ can provide the better their clients will be when they move into the home.


Comments (3)

Bill Salvatore - East Valley
Arizona Elite Properties - Chandler, AZ
Realtor - 602-999-0952 / em:

Thank you for sharing the information. Wishing you continued success.  Have a wonderful day and sell a house.  Bill

Jan 16, 2023 06:10 AM
Will Hamm
Hamm Homes - Aurora, CO
"Where There's a Will, There's a Way!"

Hello John and great information to share with us in the here in the Rain.  Make it a relaxing day!

Jan 16, 2023 08:51 AM
Richard Weeks
Dallas, TX
REALTOR®, Broker
Great information, thanks for sharing.  I hope you have a great day.
Jan 17, 2023 03:16 AM