Understanding Chimney Fire is Essential for a Homeowner

You can prevent a chimney fire only when you fully understand it. It becomes easy when you apprehend the factors that accompany and sometimes cause chimney fires.

What are those factors? How do they affect a chimney? And how can homeowners identify them?

We’ll discuss it here.

Chimney fire can become explosive


A chimney fire can become explosive. It can create noise and generate flame so the neighbors or bystanders can identify it. A chimney that has caught fire may release dense smoke from its top, seeing which people who are passing by report fire.

Homeowners sometimes report they heard a resonant sound as if a freight train was passing or an airplane was flying low. It’s a strange sound and difficult to describe. But if you hear any such sound coming from your chimney, immediately look for fire.

Slow burning chimneys

The problem with a slow-burning chimney fire is it doesn’t have enough air or fuel to become visible. Albeit undetectable, a slow-burning chimney fire can quickly reach a very high temperature and cause a mentionable damage to the chimney. The flammable materials scattered around the house can be in danger too.

Creosote is the culprit

Creosote has either a black or a brown appearance. It is a gooey and sticky substance. It’s highly flammable and can build up in high quantity inside the flue. A high temperature in the flue creates a perfect recipe for chimney fire.

Factors that lead to the buildup of creosote are following:

  • Burning unseasoned wood.
  • Chimney temperature being cooler than normal.
  • Restricted air supply.
  • Cracks in an unlined chimney allowing the deposition of creosote.

Preventing creosote buildup

To prevent these factors from becoming active, a homeowner needs to do the following:

  • Keep the glass doors open, so the supply of air doesn’t get restricted. As we’ve seen above, restricted flow of air can result in the deposition of creosote, so a homeowner needs to make sure the house is getting an abundant supply of air.
  • If the homeowner has an open fireplace, he needs to keep the dampers wide open. Can he control the amount of air that goes into the fireplace? If he can, then he could leave the dampers a bit closed, or else, leave them wide open.
  • It’s unhealthy for the smoke to stay inside the flue. The heated smoke moving quickly from the top of the chimney can increase the longevity of the flue liner.

Unlined chimney flues

Such chimneys are at a greater risk. An unlined chimney flue drafts badly. As the brickwork is unlined, it creates plenty of nooks, crevices and shelves and the smoke navigates around them before it finds an exit from the house. All that a liner does is smoothen up the smoke’s path and renders better draft.

Homeowners tend to overlook the cracks found on an unlined brickwork. Those are tiny holes and allow for CO and sparks of fire to reach those areas of the home that are susceptible to fire due to the presence of combustible materials.

Hence, if the chimney flue at your home is unlined, make it an emergency to install a liner. When you install one, it reduces fire risks by stopping the flammable by-products from reaching the inside areas of your house.

How hot the stove burns?

The homeowner needs to identify the optimum burning temperature. He needs to know which temperature is too hot, and which is too cool.

More than 250°C temperature is considered too hot. This temperature is normal during the initial inflammation, but not during the standard operation of the chimney.

Less than 110°C temperature is considered too cool. It’s normal when the appliance starts to cool down. But during the standard functioning of the chimney, this temperature is considered abnormal. The stove, therefore, should ideally burn at a temperature, which is well below 250°C and well above 110°C.

Signs of a chimney fire

It’s difficult to recognise the signs of a chimney fire. For example, creosote in the flue doesn’t necessarily indicate the presence of a fire. Unless the creosote is viscous and puffy, the odds are low that it will cause a fire.

The possible signs of a chimney fire are the following:

  • The flue tiles being cracked, or having large chunks missing.
  • The rain cap being worn out and discoloured.
  • A television antenna attached to the chimney, which is damaged by heat.
  • Evidence of the roofing materials being damaged because of creosote.
  • Cracks in the masonry on the outer side of the chimney.
  • Smoke escaping through the mortar joints.

Upon finding any of the signs, a homeowner should call up a CSIA certified professional chimney sweep and have the issue fixed. Or else, the chimney will be exposed to the dangers of fires.

About the author:

Adrice White is an experienced Chimney sweep in Paddock Wood, Kent, TN12. He takes an interest in writing articles on smokestack cleaning. He has been in this field for the last 10 years. You can avail more information about Chimney sweep Tunbridge Wells from his recent articles and blog posts.

Erin Emanuel