Signs of a Chimney Fire

10/28/2020 (Permalink)

Built-up creosote can cause slow burning or explosive fires in your chimney.

You may find chimney fires described as loud, explosive, or dramatic, with flames shooting out the top of your chimney that can be seen by your neighbors. But in fact, most actually go undetected and don't turn into dramatic explosions until they've built up or have already been burning for quite some time. Regardless, these fires can put your home in serious danger and should dealt with at their first signs.

First - What Causes Chimney Fires?

Fires in your chimney are caused by a build up of creosote, which is highly flammable and can ignite if a stray spark travels up the flue or the fire is burning at an extremely high temperature. These fires can burn for a long period of time, as the built up creosote acts as fuel to sustain a slow burning chimney fire.

Creosote builds up when the substances produced by the combustion of the fire flow from the hot hearth and up the cooler chimney, causing condensation. This condensation causes highly combustible creosote buildup in the chimney flue, which can lead to a fire.

Once creosote begins to build up, it will continue to worsen over time until your chimney is serviced. Creosote buildup restricts the air supply of the chimney, creating conditions that encourage more of the sticky substance to build up in the smoke chamber. The slower smoke moves through a chimney, the more time there is for it to cool and for creosote to condense on the liner.

Chimney Fire Symptoms

Many of the following symptoms of chimney fires may only be found by a professional chimney sweep, as the evidence may be on your roof or in your chimney where you cannot see. Even though you may not be able to spot some of the following signs yourself, you should be fine if you have your chimney inspected and cleaned by a certified technician once a year.

Signs of a chimney fire include:

• Puffy or honey combed creosote indicates there has been a fire in your chimney.
• Warped metal chimney or fireplace components indicates levels of high heat in your chimney system, possible a symptom of a fire.
• Cracks in the flue tile indicate your chimney has rapidly heated or cooled down.
• Discolored or warped chimney cap caused by intense heat. A chimney fire may cause the screen to warp and distort as well.
• Heat damage to things on your roof, such as satellites or TC antennas.
• Cracks in the exterior masonry of the chimney.
• Seeing smoke escaping from anywhere but the top of your chimney.
• Creosote flakes or pieces on the ground outside your home, or dropping down your chimney as they burn off.
• Damaged or melted roofing materials.

When you identify any of the above signs of a slow burning chimney fire, you should stop using your fireplace and have it inspected by a certified chimney sweep to prevent a possible house fire. Depending on the extent of the issue, your chimney may only need to be cleaned, have a few tiles replaced, or be completely rebuilt.