How to Clean a Chimney

Chris Tice
Chimney cleaning

Chimneys are a very important part of your home's heating system and without proper attention, they can be dangerous hazards. Proper inspections and regular cleaning of your chimney will help you keep a warm and safe environment for generations.

Check Chimney Degradation Before Cleaning

Degradation of your chimney, whether it's brick and mortar, stove pipe, or a combination of the two, is very different, even though cleaning is very similar. Be sure you know what signs and symptoms of internal damage to look for both before and while cleaning your chimney. If any of these problems appear, call a professional to inspect your chimney; if you have a combination chimney, you might need a pro to take a look before you clean.

Brick and Mortar

Hot and cold expansion over the years will cause mortar and bricks to move and could pose a two-fold hazard: smoke intrusion and possible collapse. What to look for during the cleaning process:

  • Non-blackened brick or mortar pieces in firebox or on smoke shelf
  • Loose crumbling mortar on the exterior of the mantle or chimney
  • Rusted or broken damper

Stovepipe

The type of steel piping will depend on how well your chimney stands the test of time. Galvanized steel will eventually flake from the expansion of the pipes which may promote rust where stainless will not.

A simple test using a magnet will reveal your pipe material; galvanized steel will attract the magnet while stainless steel will not. You can now narrow down the signs of deterioration in your chimney during cleaning:

  • Pipe connections loose or slipping between sections
  • Rusted metal flakes in firebox (galvanized pipes)
  • Rusted or broken damper (the damper might be a different metal from pipes)

Combination Pipe and Brick

Be aware of stovepipe indications as listed above during cleaning but signs of mortar failure will not show up during the cleaning process. A visual inspection of your brick and mortar exterior will be necessary so pay close attention to the following areas before cleaning.

  • Loose crumbling mortar or bricks on the mantle and chimney which may indicate hidden damage behind the walls.
  • Water intrusion between brick and pipe areas from the rooftop which could cause decay from within.
  • Pipes loose inside mortar at top of chimney.

Any of these indications could show signs of serious problems between the brick and pipe so get a professional inspection before you clean.

Cleaning Your Chimney

Before doing anything, clean the fireplace first! Many clues to chimney health lie at the bottom of your firebox and this could help you decide if you need to call a professional before you get in there. If flakes of rust or pieces of brick and mortar are in your ash before cleaning the chimney the cleaning process below could knock out loose bricks or dislodge rusted pipes. Call a pro and make them aware of what you found before you go any further!

Tools

  • Chimney Cleaning Tools
    Ladder
  • Pliers and screwdrivers
  • Wire brush
  • Goggles
  • Dust mask
  • Gloves
  • Flashlight
  • Long sleeve work shirt with hood
  • Drop cloths or old sheets
  • Quality chimney brush and pole

The chimney brush should be 2 inches wider than your flue's widest dimension with a minimum pole combined length that's 10 feet taller than your house.

Process

  1. Climb ladder to access roof. Use pliers or screwdriver to remove chimney cap.
  2. Climb back down and return to the room with the chimney.
  3. Open windows in room where fireplace is present. Open damper. Ensure good airflow up through chimney before entering firebox.
  4. Set sheets around fireplace entrance for easy cleanup.
  5. Use a wire brush to clean damper, checking for damage/rust with flashlight.
  6. Sweep off smoke shelf and check for decay in mortar. (brick chimney only)
  7. Connect one section of pole to chimney brush and push past damper.
  8. Continue pushing brush up, adding poles when needed, till the brush is clear of the pipe at the roof. Do not reverse direction of the brush inside the chimney. This could cause bristles to break, mortar to break free, or steel pipes to come apart. You want to prevent chimney repairs - not cause them!
  9. Pull back down, removing pole sections as needed, until brush is clear in the firebox.
  10. Repeat steps 7 and 8 until dust and debris is minimal.

If a simple brush won't do the trick, Anti-Creo-Soot Creosote Remover could help. Spraying it around your fireplace and directly on your logs while burning will break down thin layers of creosote in your chimney and assist stubborn removal without creating more work.

Approximate Cleaning Time and Safety

Chimney cleaning will take a few hours depending on buildup so allot time as needed and keep animals and children clear of the room. Creosote and soot are lightweight and can cause irritation to lungs, sinuses, eyes, nose and throat.

Cleaning Frequency and Combustibles

The type of combustible burned in the chimney determines not only how difficult the cleaning process is, but also how often you must repeat it.

Smoky Combustibles

Smoke causes soot and creosote that will line your chimney walls, restricting your airflow and choking your fire, which in turn causes more smoke, so make sure you are burning the cleanest of materials. Otherwise, you may be cleaning your chimney more often than you would like. Smoky combustibles include:

  • Unseasoned wood (wet)
  • Construction material (treated wood)
  • Prefab fire logs (burning more than one at a time)
  • Homemade paper logs (cheapest to burn)
  • Newspaper fire starters

Non-Smoky Combustibles

If you burn these combustibles, you probably won't have to clean your chimney as often.

  • Seasoned wood
  • Dry leaf fire starters
  • Twigs and stick kindling

Even the best purchased kiln dried wood will smoke. For best results purchase pre-split wood six months in advance, let dry outside in a ventilated area, off the ground, and protected from the elements before burning. This will eradicate most of the moisture from the wood causing a cleaner burn.

Check Chimney Monthly Regardless of Combustibles

Depending on the above combustibles, you should check your chimney monthly (or more) during the burning season to prevent fire hazards. If you are burning seasoned wood you may not have to clean your chimney at all! If soot and creosote line the chimney, they can catch fire. Every time that layer gets thicker than the width of a nickel, clean the chimney.

Clean After Last Spring Use

Say your chimney burns clean throughout the whole winter and you never reach the nickel depth, awesome! But after the last burn in the spring, regardless of soot depth, always do a final clean to prevent buildup over the summer. Letting that little bit of soot and creosote fester over the hot moist summer months will only add up over the years and could harden. The soot is driest and will be easiest to remove the day after the last burn in the spring so take the opportunity to clear out that winter buildup.

If you do have a cold snap and must burn more wood after the spring cleaning don't worry. The soot from a couple burns would be minimal so waiting to clean after the next burning season won't create a problem.

Know When to Call the Professionals

Chimney sweep

If you already have more than a nickel's worth of solid glazed creosote or hardened soot that a brush wouldn't scratch, then it's time to call a professional. Rotary whips and chains will cut through that hardened stuff, but they can also cut into your chimney pipe or brick causing serious problems for the beginner. They also cost more money and are less useful once the preventative maintenance is scheduled, so call a professional and have them reset your chimney's clock so you can take over the care of your chimney with ease.

When loose rusted pipes, crumbling mortar and broken bricks are present you should always call a qualified chimney professional. Smoke could permeate your house if the chimney is not sealed properly and rebuilding crumbling chimneys could cause more problems than you think.

The Right Cleaner for the Job

If learning how to clean a chimney isn't up your alley, or you have any of the issues mentioned, hire a pro. Professionals have the tools and the know-how to rebuild and replace damaged parts safely as well as prevent non-chimney related issues such as leaking roofs and possible contact fire hazards. Make sure you find three certified professionals, check for recommendations, and find the right match for you before you hire!

How to Clean a Chimney