The United States sees more than 25,000 chimney fires each year, costing the nation $125 million in property damage.
Whether you use hardwood, softwood or compressed logs to fuel your fireplace, several by-products like smoke, water vapor, hydrocarbons and tar fog are released into the flue. As these substances exit through the chimney (which is relatively cooler), they condense on the inner surface, forming a sticky residue of combustible creosote and tar on the inner walls.
From hiring an annual chimney cleaning service to using special chimney-cleaning logs or chemicals, several techniques have been used by homeowners to reduce creosote and tar buildup in the chimney. Though creosote sweeping logs (CSL) aren’t adequate in cleaning and maintaining the chimney, this post offers useful information on how they can be used along with the conventional chimney sweep.
Let’s first understand the factors that lead to the formation and accumulation of creosote and the hazards of not getting rid of it.
How creosote accumulates
Firewood that’s green or not dried sufficiently creates lesser heat output as a lot of energy is used in drying excess moisture in the wood. Due to the lack of heat, the smoke generated condenses quickly, forming creosote and tar deposits in the flue.
If your flue is oversized and long, chances are that the smoke from the fireplace will hang around in the chimney for longer than normal (also referred to as residence time). The higher the residence time, the greater the creosote buildup.
If the flue gas temperature is lower than normal, the smoke will condense early, causing the formation of creosote. Metal chimneys and chimneys located on the exterior wall of a house are at high risk of creosote buildup. This is because the flue temperature in such chimneys is abnormally low due to the heat loss.
If you pack your fireplace with a lot of firewood and close its glass door tightly, the air supply is restricted, encouraging creosote buildup. The accumulation will be faster if your chimney’s dampers are left closed. This is because the restricted airflow prevents the smoke from leaving the chimney, increasing the residence time.
Hazards of creosote buildup
If not treated on time, creosote can build up and cause the following issues in your chimney:
- The flue will be choked-up, limiting the airflow and reducing the efficiency of your wood stove or fireplace
- Creosote is combustible, so its buildup can cause a chimney fire
- The reduced draft will allow dangerous toxins into your house
Therefore, it’s wise to involve a chimney sweep, who can assess the health of your chimney, preventing potential fire hazards.
Creosote sweeping logs: How do they work?
Creosote deposits are extremely slick and black or brown residue renders a flaky or drippy texture to the inner walls of the chimney or stove pipe. This glazed layer is tough to remove by mechanical brushing alone, especially if your chimney has third-degree glazed creosote deposits.
CSL are logs impregnated with a potent chemical mixture that can alter the adhesive composition of the creosote layer, turning it into a brittle or powdery texture. The smoke from creosote sweeping logs contains active minerals and additives that are carried up the flue and settle on the creosote deposit. Over the course of subsequent fires, the active chemicals in the vapors alter the glazed nature of the deposits, making it easy for the chimney sweep professional to break it down and clean the chimney.
Pros and cons of using creosote sweeping logs
The biggest reason why CSL is widely used is that the user has to merely unpack the logs and place them in a lit fireplace. Moreover, these logs are reasonably priced and can be stored for a long time.
Another plus is that several chimneys are bent in shape or lengthy, making it tough to manually clean the hard-to-reach areas, where the creosote may have deposited. CSL is ideal for such chimneys as its vapors penetrate the creosote deposits in these areas, helping chimney service experts get rid of it with ease.
However, the aggressive marketing of creosote sweeping logs can mislead consumers, making them think that this product performs functions equivalent to a chimney sweep. CSL is a great product but it cannot be considered a substitute for a chimney sweep.
Professional chimney sweeps perform pre-emptive chimney inspection and clean the smoke ducts, flue pipes and fireplaces, thereby reducing the risk of fire hazards.
And after the use of CSL, the creosote flakes fall to the bottom or get trapped in the bends of the flue, increasing the risk of chimney fires. One of the pertinent tasks accomplished by chimney sweeps is to get rid of the accumulated debris in the chimney and fireplace.
Thus, CSL alone is not an all-inclusive chimney maintenance solution, but an effective tool that helps chimney sweep professionals effectively clean and repairs the chimney.
Though creosote sweeping logs can be effectively used in fireplaces that use wood, they cannot be used in natural gas or propane-powered fireplaces as they require a wood burning fireplace. Moreover, no CSL brand guarantees the complete removal of the accumulated creosote.
The Washington Public Fire Educators point out that creosote sweeping logs can also increase the risk of chimney fire. This is because, after the use of CSL, the creosote undergoes intense combustion to form an ash-like residue. This combustion increases the risk of an uncontrolled chimney fire. It can also cause the creosote flakes to leave the flue and fall into the fireplace, causing hazardous fire spurts.
Without a doubt, creosote sweeping logs can reduce the amount of flammable creosote in your chimney and avert fire hazards. Yet, the best way to prevent chimney fires and accidents is to involve a chimney sweep to clean and inspect your chimney.
Jesse Peralta is the founder of Chimcare, a family owned business in the Pacific Northwest engaged in chimney services. The team is professional in the field, offering expert advice pertaining to chimney sweep. Also, they have extensive knowledge and expertise in managing chimney services in Seattle including cleaning, repairing, other masonry services and much more.
