Fireplace Cleaning: When to Clean a Chimney Flue

How often to remove creosote to prevent chimney fires and do a fireplace cleaning.

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How to Tell When it’s Time for Chimney Cleaning

There isn’t a simple rule of thumb on how often to clean your chimney, such as cleaning after 50 uses or one year. But it’s still an important task, as a smoky fire without enough oxygen emits lots of unburned tar vapors called “creosote” that can condense inside the fireplace flue and stick to it, possibly leading to a chimney fire. You can reduce creosote buildup in your fireplace flue by providing adequate combustion air, which will encourage a hot, clean-burning fire.

How to Check for Creosote

To check for creosote yourself, first, make sure there’s no downdraft from the chimney. If you feel an airflow, open a door or window on the same floor as the fireplace until the downdraft stops or reverses and air flows up (tape tissue to the fireplace opening and watch its movement). Then, while wearing goggles and a basic disposable dust mask, take a strong flashlight and your fireplace poker and scratch the black surface above the damper (smoke chamber).

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If the groove you scratch in the creosote is paper thin, no cleaning is needed. If it’s 1/8 in. thick, schedule a fireplace cleaning soon. If you have 1/4 in. of creosote, do not use the fireplace again until it is cleaned—a chimney fire could occur at any time.

The easiest creosote to remove is the feather-light dull gray, brown or black soot. The next form is a black granular accumulation, removed fairly easily with a stiff chimney brush. The third type of creosote is a road tar-like coating that is much harder to remove even with stiff chimney brushes, scrapers or power rotary whips. The final (and most deadly) is a shiny, glaze-like coating on the fireplace flue that is virtually impossible to remove.

Required Tools for Cleaning a Fireplace:

Have the necessary tools for this chimney cleaning DIY project lined up before you start—you’ll save time and frustration.

  • Dust mask
  • Flashlight
  • Safety glasses

Fireplace Cleaning: How to Remove Creosote

You could try to remove creosote yourself, but for a thorough job, call a chimney sweep who’s certified by the Chimney Safety Institute of America. Make sure the sweep you hire ($150 to $200) does more than pushing a brush. A chimney sweep needs to be knowledgeable about building codes, trained to recognize deterioration or venting problems and able to advise you regarding the chimney’s condition. The National Fire Protection Association recommends that chimneys, fireplaces and vents be inspected at least once per year. Here are tips on how to clean a chimney.

Another, idea to try out when it’s time to clean your chimney is a chimney sweep log. A fireplace cleaning log helps to prevent chimney fires and they help remove debris deposited along the chimney walls. These sticky deposits are called creosote. Creosote deposited over a long period becomes highly flammable and it’s often the cause of chimney fires. Creosote removal is vital to your safety. Sweeping logs are popular because of their ease of use for creosote removal. All you have to do is unwrap the log from its package and place it in a lit wood burning fireplace.

Get a chimney sweep log on Amazon.

Chimney Cleaning Cost Tip:

Save money and avoid a long wait by having a chimney inspection and fireplace cleaning in the spring.