What You Need to Know About Chimney Fires

Today, the experts at Chimney Sweeps of America in Denver, Colorado discusses what you need to know about chimney fires. Being an educated homeowner is the best way to prevent damaging your home and putting your family in peril. Each year there are over 20,000 chimney fires in America. The majority of them can be prevented through proper cleaning, regular maintenance and an educated homeowner who knows when to call the professionals. Let’s take a closer look at chimneys.

The purpose of the chimney is to make the fireplace safe to use. It channels smoke up and out of your home while protecting the surrounding building materials from fireplace gases that could heat them to the point of ignition. If this structure is not functioning correctly, your fireplace could be dangerous.

Creosote Buildup

Certainly, one of the biggest reason for chimney fires is a dirty chimney. This is most often a build-up of a substance called creosote inside of the chimney. This is why cleaning is so crucial. If this creosote is never allowed to build up, the chances of a chimney fire are dramatically reduced.

Where does the creosote come from? Fire creates several byproducts. These byproducts include a number of things including:

  • Water vapor
  • Gases
  • Smoke
  • Ash
  • Tar
  • Hydrocarbons
  • Minerals

It is the job of the chimney to provide a way for those byproducts to get out of your home safely.  The trouble starts because these byproducts begin to cool down as they travel up the chimney and get farther away from the fire. The change in temperature causes condensation to occur which then causes these byproducts to stick as residue on the inside of your chimney. This is what we call creosote.

Creosote doesn’t always look the same. It can be brown and black in color, and its consistency can vary quite a bit. It can be anything from flaky and crusty to tar-like to shiny and hard. Regardless of how it looks, it is extremely flammable. Once it builds up enough, all it needs is enough heat to catch on fire. Unfortunately, the inside of a chimney offers more than enough heat to ignite creosote.

Contributing Factors to Creosote Buildup

Whenever a fire burns in your fireplace, creosote is slowly accumulating in your chimney. There are several factors, however, that can contribute to that creosote building up faster. By avoiding these causes, your chimney will be safer, work more efficiently, and you won’t have to clean it as often.

Chimneys need plenty of airflow to carry all those byproducts out of your home safely. Without it, creosote builds up faster. As you can imagine, this restricts the airflow even more, and it becomes a vicious cycle that makes the problem progressively worse.

There are some ways that you can unknowingly contribute to the problem. If you tightly close the glass doors on your fireplace, especially when the fire is getting started, it can’t get enough air to channel the byproducts up the chimney. Also, make sure that the damper is always open wide enough.

Burning unseasoned wood can also contribute to creosote buildup. Because of the water content, it’s harder to get burning, and the resulting smoke is cooler, meaning it moves slowly up the chimney. That gives it a chance to leave more residue behind as it passes through. Overstuffing the firebox full of wood in an attempt to make it burn longer also contributes to this problem.

Signs of a Chimney Fire

Some chimney fires can be dramatic. You may hear a loud popping noise or a rumbling sound like that of a freight train. You may notice an intense, hot smell and see dense smoke or flames shooting out the top of your chimney.

But those are only the dramatic ones. The vast majority are not so noticeable. Sometimes a homeowner doesn’t even know a fire happened until their next inspection. After a fire, a damaged chimney is now at even higher risk for a chimney fire that could do more severe damage.

The following signs will tell your chimney sweep that a fire occurred in your chimney at which point they can advise you on a remedy.

  • Cracks in the outside masonry
  • Discoloration of the rain cap
  • Flakes or pieces of creosote on the roof
  • Roofing material melted by hot creosote
  • Signs that smoke is escaping the mortar joints of a masonry chimney
  • A nearby TV antenna damaged by heat
  • Cracked flue tiles
  • “Honey-combed” or puffy looking creosote
  • A damper or smoke chamber connector pipe with warped metal

If you happen to notice any of these signs, call a professional immediately. Don’t use your fireplace until someone has thoroughly inspected it. If a fire has already damaged a chimney and you keep using it, you run the risk of it causing the surrounding house materials to catch on fire. Chimney damage is a dire situation and can cause extensive property damage, not to mention put your family at risk.

Avoiding Chimney Fires

The best way to avoid chimney fires is to keep the chimney clean and well-maintained. Without creosote build-up inside, it is unlikely that a fire will occur. When a CSIA-certified sweep cleans your chimney, they’ll also inspect everything, watching for any signs that an undetected fire has occurred inside the chimney. They will also check for any weaknesses that could indicate a fire may be about to occur.

Plan to have your chimney checked at least once a year. If you use your fireplace a lot, you may want to consider having it checked more frequently. You can ask your sweep what they recommend based on your particular usage.

We hope this information has helped you understand what you need to know about chimney fires. If it has been a while since your last chimney cleaning and inspection, or you’ve recently purchased a home and don’t know its chimney cleaning history, give us a call today to set up an appointment. At Chimney Sweeps of America, we have trained CSIA-certified staff at the ready to inspect your chimney.

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