The Risks of Creosote Buildup

Creosote is a flammable substance that accumulates when a wood fireplace is used. You can’t completely avoid having creosote in your chimney, but you can create less of it and have it safely removed periodically.

Ye Olde Brit Chimney Sweep of San Bernardino, CA, would like to cover some of the risks of excess creosote buildup and what to do about it.

What is creosote?

Creosote is the result of smoke condensation in a chimney flue. It can be flaky, puffy, sticky, or solid. In all forms, it’s highly flammable and is the cause of most chimney fires throughout San Bernardino and Southern California each year.

The 3 stages of creosote

Creosote can exist in three different stages.

Stage 1: A thin, flaky layer that’s fairly easy to remove.

Stage 2: Beginning to look like tar, stage 2 creosote is harder to remove.

Stage 3: Here, the substance is definitely tar-like and can even be solid. Stage 3 creosote should be removed only by a professional chimney sweep with the proper equipment.

Draft obstructions

When creosote builds up in a flue, it narrows the smoke passageway. When constructed, the chimney was specifically sized to draft the fireplace it was connected to. A narrower flue means the draft will be hindered.

When the flue is obstructed, smoke and deadly carbon monoxide can back up into the home. Carbon monoxide is a particular concern because it can’t be seen or smelled. You won’t know it’s there until symptoms appear.

Chimney fires

As noted, most chimney fires are started by ignited creosote. Some chimney fires are big, blazing events; others are quick and small, and they start and go out on their own. But all chimney fires can cause damage to a chimney liner and other parts of the interior chimney system.

Acidic damage

In addition to being flammable, creosote is highly acidic. The longer it stays in contact with a chimney liner, the more likely the liner will suffer damage. A broken liner puts the house at risk of a fire. It can also allow carbon monoxide and other combustion gases to escape the flue.

Creating less creosote

You can’t have a fire with no smoke, but you can have a fire with less smoke. Here are some tips.

• Use only dry firewood: Damp wood makes a lot more smoke.
• Keep your flue clean: Flue obstructions hinder the draft, which means less air coming through the log stack, leading to a smoky fire.
• Turn off exhaust fans: If you’re having drafting problems, bathroom and kitchen exhaust fans may be pulling air away from the fireplace.
• Burn only firewood: Items like clothing, pressed board, sheetrock, plastics and furniture pieces create a lot of smoke. They can also send dangerous toxins into the air.

Removing creosote

If it’s been more than a year since your last chimney inspection, this is the place to start. Your inspector will determine the level of creosote in your flue and recommend a cleaning schedule that will keep the substance from getting out of hand.

Professional chimney sweeps use specialized brushes, rods, whips, chains, solvents and vacuums to safely remove all stages of creosote. Most fire safety and hearth organizations in the U.S. recommend annual chimney sweeping to keep the chimney safe and operating at peak efficiency.

Is it time to clean your chimney?

Ye Olde Brit is ready to help with chimney inspections and cleaning throughout the greater San Bernardino region. We carry the Certified Chimney Professional designation, and our technicians are fully trained in all phases of chimney service.

Speak with a chimney expert today at (909) 880-2120. You can also get in touch with our handy contact form.