Company Blog

CREOSOTE IN THE CHIMNEY– What’s the big deal?

What's the Big Deal With Creosote?Creosote happens when you burn a fire. Burning fires all winter long and some during the “bridge” seasons, can lead to a large enough accumulation of creosote in a chimney flue to cause problems.

Each and every fire results in small amounts being deposited onto the sides of the flue. Traces of creosote are in the smoke that rises from fire. As the smoke travels upward and mixes with cooler air and moisture nearer the top, it liquefies and then solidifies and sticks to the inside of the chimney. This narrows the passageway, which restricts ventilation, which in turn causes more creosote to accumulate. As efficiency decrease with your fireplace, more creosote is accumulated in the flue. If left unaddressed, this process will continue (layer by layer) until something happens (i.e. achimney fire or blockage) that renders the chimney unusable.

What’s wrong with creosote? Is it really dangerous?

The main issue with creosote is that it’s flammable. It burns…layer by layer. As the amount of creosote inside the chimney flue increases so does your risk of a serious chimney fire. Worst case scenario, chimney fires can cause loss of homes and lives. Less seriously , but still expensive to repair, chimney fires can break the inside of your chimney. The National Fire
Protection Association Standard 211 stipulates that cracked flue tiles must be repaired or replaced.

How to prevent creosote buildup….

The key is regular maintenance. You can interrupt the layering process by having your chimney inspected annually and cleaned whenever the buildup is sufficient to need removal. When you schedule regular service, your creosote buildup will be minimal. Stage 1 and Stage 2 creosote (see our previous blog about creosote) can often be removed by traditional or rotary brushing systems. Stage 3 (the tar like stuff) will not brush out and requires a specialized removal process. Our technicians are trained in various glazed creosote removal options and can determine which is best for your situation.

Dry seasoned wood can help with creosote build-up, but more importantly not inhibiting airflow to the fire and not slowing the speed of the gases exiting the chimney will make a greater impact on the amount of creosote that forms in your fireplace or woodstove flue.

The benefit of annual inspections…..

The Chimney Safety Institute of America (CSIA) and the National Fire Protection Association (NFPA) both recommend annual inspections to keep your chimney operating efficiently and to minimize risk factors. Our trained technicians inspect your system from top to bottom to determine any factors that impact safety, usability and functionality. Our report lets you know any issues we find and corresponding suggested resolutions.

If you have concerns about your chimney system, call schedule a visit with our professionals at Blue Sky Chimney Sweeps|Bless Your Hearth now!

Creosote F.A.Q.

One of the leading causes of chimney fires, according to the Chimney Safety Institute of America (CSIA), creosote build-up is a dangerous fact of life when you have a wood-burning fireplace or stove. Removing creosote deposits from your chimney walls is a big part of your annual chimney sweeping, and this maintenance can save you and your family’s life since creosote building up on your chimney walls puts you at risk of a chimney fire.

It isn't possible to clean 100% of the creosote in your chimney. However, you need regular maintenance to keep the level low.

It isn’t possible to clean 100% of the creosote in your chimney. However, you need regular maintenance to keep the level low.

The CSIA-certified chimney sweeps at Blue Sky Chimney Sweeps clean your chimney thoroughly to remove any creosote sticking to your chimney walls when performing their chimney sweeps. We at Blue Sky Chimney Sweeps would like to answer some of the most frequently asked questions we receive about creosote to inform you about this fire hazard.

What exactly is creosote and how does it get in my chimney?  Occurring naturally, creosote is the resulting residue of the condensation that occurs when the by-products of combustion (smoke, gases, vapors, unburned wood particles, tar fog, and other assorted minerals) leave the fireplace or wood stove and exit the cooler upper chimney. This residue sticks behind on the chimney walls.

What does creosote look like? Varying in appearance, creosote can be either black or brown, and it takes different forms: sticky and tar-like, flat and shiny, and crusty and flaky. No matter what it looks like, creosote is highly combustible in every form.

How does creosote build-up start chimney fires? If the build-up is large enough and your internal chimney flue temperature gets hot enough, a chimney fire could ignite, thanks to the highly combustible makeup of creosote.

Are there conditions that encourage the development of creosote deposits? Yes, certain things to help creosote to build up more quickly: restricted air flow, burning unseasoned wood, and cooler than normal chimney temperatures.

What can I do to change these conditions? To keep air flowing properly and without restrictions, open the glass fireplace doors when burning a fire, and always be sure your damper is wide open when burning a fire. You want to be sure you have enough air flowing into your fireplace to move heated smoke up the chimney quickly because the longer the smoke stays in the flue, the more likely creosote will form. When using a wood stove, do not close down the stove damper or air inlets too soon or too much. Always use seasoned firewood because burning unseasoned wood keeps the smoke cooler because the fire spends so much time burning off the excess water in the wood cells. Also, when using a wood stove, never overload the firebox with wood in an attempt to get a longer burn time because this also adds to creosote development.

What is the best way to prevent the accumulation of large creosote deposits? As the CSIA says, “clean chimneys don’t catch fire.” Having your chimney swept annually by a CSIA-certified company like Blue Sky Chimney Sweeps is the best possible prevention of creosote building up large enough to ignite a chimney fire. Our chimney sweeps are well experienced with creosote removal, and can rid your chimney walls of all creosote deposits.

If you have more questions about creosote and chimney fires, contact Blue Sky Chimney Sweeps today. We will be happy to schedule an appointment for your annual chimney cleaning to give yourself peace of mind regarding a possible chimney fire.