When and How to Clean Your Chimney

Chimney sweep

 

Philartphace / Getty Images

Overview
  • Total Time: 2 - 4 hrs
  • Skill Level: Advanced

Nothing says home like a wood-burning fireplace. Gas-powered and gel fireplaces have their strong points, especially when it comes to ease of use. But only a real wood-burning fireplace, with its deep crackle and glowing orange embers, is capable of sparking romance and comfort. However, having a wood-burning fireplace requires serious maintenance. A poorly maintained chimney can lead to a sooty, smelly home interior and a terrifying phenomenon known as a chimney fire.

There are a few ways to clean your chimney yourself. Climbing on your roof is one common method that can be a one-person job with an assistant to help with the ladder. Cleaning the chimney from inside your fireplace is one of the messiest jobs imaginable, so it's best left to professionals.

What Causes a Dirty Chimney?

Wood fires do not burn clean. When wood burns, it releases a host of contaminants that coat the inside of the chimney. Organic, flammable debris can enter the chimney, brought by the elements or by birds, vermin, and other animals. In addition, wind can deposit leaves and twigs in chimneys lacking flue caps. But the real problem in a chimney that needs attention is creosote, which is very difficult to remove, even with DIY methods.

What Is Creosote?

Creosote is an oily, black substance that is a contaminant byproduct of wood-burning fires. When fires burn in the fireplace, they release smoke, water vapor, gases, wood particles, tar fog, and other pollutants. These create a flammable residue on the inside of the chimney in the form of creosote. It condenses on the inside of the chimney until it's removed, and is found in three stages: ash (stage one), flaky (stage two), and glazed (stage three). If you have a thickness of more than 1/8 inch of it on the walls, it needs to be removed.

Why You Must Clean Your Chimney

Without cleaning your chimney regularly, you will begin to experience a slowdown in wood burning. Fires will be more reluctant to start, and they will not burn with as much vigor as before.

But the main reason to clean a chimney is to avoid a chimney fire. Chimney fires begin with snaps and pops as loud as gunshots, progressing to a deep rumbling sound. Oily, black, flaming creosote rains down into the firebox.

What Happens During a Chimney Fire

When the fire starts, it starts like an explosion. Flames blast out of the top of the chimney and back down into the firebox. Due to thermal expansion, the flue may crack at some unreachable mid-point and shoot flames into the walls from the inside.

Chimney fires typically cannot be controlled by the homeowner. Because firefighters have to shoot water from the top downward, the house suffers damage from flooding. In many cases, the entire house is lost.

When to Clean Your Chimney

Chimneys should be cleaned no later than the early fall, before fire burning season. If you choose to hire a chimney sweep, you can expect a quick turnaround if you have them come earlier, ideally in the summer. For self-cleaning, late summer is the best time, since you can count on a dry, safe roof and the mild conditions that you'll need to do the job. 

In addition to scheduled chimney cleanings, you should clean when any of these conditions are present: 

  • Soot and creosote tend to fall into the firebox when there's a fire in the fireplace
  • Honeycomb textured creosote builds up on the inside of the chimney
  • Creosote is more than 1/8 inch thick
  • You burn a lot of artificial logs
  • You are a heavy fireplace user
  • You burn green or otherwise unseasoned firewood

Safety Considerations

Most homeowners choose to call in a chimney sweep, especially if the chimney has not been cleaned in a long time. Find a reputable chimney sweep company by asking friends and neighbors for their recommendations. Ask potential companies if they are certified by the Chimney Safety Institute of America (CSIA) or if they are a member of the National Chimney Sweep Guild (NCSG), both of which promote safety and professionalism within the chimney sweep industry.

If you are extremely comfortable with heights and experienced with scaling your home's roof, it's possible to clean your own chimney. Stay safe by practicing good ladder safety and by having an assistant monitor you when you are on the roof.

What You'll Need

Equipment / Tools

  • Extension ladder
  • Cordless drill with a screwdriver bit
  • Shop vacuum with dust filter
  • Flashlight

Materials

  • Chimney brushes
  • Fiberglass extension rods
  • Sheet plastic
  • Painter’s tape and duct tape
  • Dust mask and safety glasses

Instructions

  1. Seal Up the Fireplace

    Downstairs, fully open the fireplace damper.

    Cut off a generous section of sheet plastic measuring about 6 feet long by 4 feet wide, and tape it on the floor in front of the fireplace with painter’s tape or duct tape.

    Cut another piece of sheet plastic so that it is at least 12 inches longer and wider than the opening of the fireplace. Tape this over the fireplace to seal it against debris.

  2. Climb Onto the Roof

    Place the extension ladder against the house so that you can gain access to the roof. Bring your chimney cleaning tools up to the roof. You will also need to bring your cordless drill and a dust mask.

    Warning

    Make sure your roof is dry before attempting to climb onto it from your ladder. Always have an assistant securely hold the ladder for safety.

  3. Remove Chimney Caps

    To access the flue, remove the chimney caps by turning out the screws on the caps with your cordless drill. Place the caps well away from you so that you do not trip over them or accidentally kick them off the roof.

  4. Prepare the Chimney Cleaning Brush

    Attach the chimney sweeping brush to the first extension rod. Keep the additional rods nearby because you will need to add them to the first rod.

    Tip

    Determine the height of your flue so you know what length brushes you'll need for the project.

  5. Scrub the Chimney

    Keeping only one rod on the brush at this time, scrub the chimney by starting at the top and slowly working downwards. Scrub until you reach the end of the first rod.

    Take your next rod and screw it onto the back of the first rod. Continue scrubbing downwards, adding more rods, until you cannot go any further.

    Eventually, you will reach the smoke shelf, typically a stopping point for most do-it-yourself chimney sweeping operations.

  6. Scrub as You Remove the Brush

    Do not remove the brush in one motion. Instead, take this opportunity to lightly scrub up and down as you pull the rod assembly upward. When you reach a joining point, remove a rod and set it aside.

  7. Inspect With a Flashlight

    Before replacing the chimney cap, look into the chimney with a flashlight to see if there are spots you missed. Repeat brushing until you don't see much left with a flashlight.

  8. Finish Roof Operations

    The roof side of this project is almost finished. Replace the chimney caps.

    Gather your tools and hand them down to your assistant.

    Exit the roof and remove the ladder.

  9. Clean the Downstairs

    At the fireplace, wait about 10 minutes for the dust and debris to settle.

    Carefully peel away the plastic covering the firebox opening and wad it up to enclose any dust that has adhered to the inside. Discard the plastic. 

    Clean visible areas that you can reach with the smaller chimney cleaning brush.

    Suck up all debris with the shop vacuum.

    Remove all tools, then wad up the flooring plastic to enclose all fallen debris.

    Discard the plastic.

  10. Properly Dispose the Creosote

    Depending on local regulations in your area, you may be able to dispose of sandy (stage one) creosote deposits in a garbage bag through your ordinary trash collection method. But always check with your local town hall or your waste disposal facility to see if there are specific guidelines or instructions for disposing of creosote you have cleaned from your chimney.

Tips to Keep Your Chimney Cleaner Longer

There are a few ways to keep your chimney cleaner and safer for longer.

  • Clean wood: Burn the driest, cleanest woods—such as hardwoods—because they have the least sap to clog up a chimney. Burning green or unseasoned wood hastens creosote buildup.
  • Blockages: Be aware of blocked a chimney flue or chimney cap, especially after storms or high winds that can clog them with debris, snow, and ice.
  • Ashes: Pay attention to fireplace ash; there is a lot of controversy over whether to remove some or all of it after a fire. Generally, it's best to leave about an inch of ash to help build and start future fires faster, which actually reduces buildup. But remove ashes at the end of a heating season and put them to use as a soil amendment, if you feel comfortable with its pros and cons.
  • Creosote buildup: Consider commercial products that you can squirt into your chimney to slow down the accumulation of creosote.

When to Call a Professional

It's best to hire a professional if the above cleaning instructions, especially climbing onto the roof, feel too challenging and unsafe.

But you should also notify a professional if you discover structural issues during your DIY cleaning which will require repairs. For example, if your brush gets caught in a crack and you haven't cleaned your chimney after a long period of disuse, you should call in a professional. There should not be any cracks in your chimney that could catch a brush. A crack has the potential to spread flames to other structures of your home.

Call a professional if you spot other problems while cleaning, such as:

  • A slightly shifting or moving chimney on the roof
  • Erosion of chimney crown
  • Spalling (breakage) of exterior chimney bricks
  • Pieces of tile spotted in the firebox, possibly indicating the extreme danger of a cracked liner
  • Flaky (stage two) and glazed (stage three) creosote, which needs to be treated with chemicals and disposed of properly
Article Sources
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Chimney Fire Precautions. United States Federal Emergency Management Agency.

  2. What to Know About Chimney Cleaning and Repair. Connecticut State Department of Consumer Protection.

  3. Frequent Questions About Wood-Burning Appliances. United States Environmental Protection Agency.