Chimney Cleaning Basics: The Three Stages of Creosote & Much, Much More

Although we have had a warm fall so far it is inevitable that winter will arrive in Groton which for many of us means firing up the wood stove. To safely burn wood you will need to clean the wood stove or fireplace chimney on an annual basis. According to Groton Fire Chief Steele McCurdy, "The Groton Fire Department sees an uptick in the number of chimney fires in the fall as residents light their wood burning stoves and fireplaces for the first time.

The Groton Fire Department strongly urges residents to have their chimneys cleaned prior to starting the first fire of the season and always to burn well-seasoned wood. The burning of wet or green wood significantly increases the accumulation of creosote and the likelihood of a fire."

The next decision you need to make is whether or not it makes sense to clean the chimney yourself. Chimney cleaning is dirty, requires a fair amount of mechanical skill and can be dangerous because to do it properly you have to get on your roof. In many cases it may make sense to hire a professional chimney sweep accredited by the Chimney Safety Institute of America to do the job for you. This article will only describe a simple scenario wherein it is safe for you to access the roof and the wood stove is attached to a simple, relatively modern metal chimney.

For houses with a high or steeply-pitched roof and older houses with masonry chimneys, we recommend hiring a professional.

If you are undaunted so far then we can proceed to the initial examination stage. First you should examine the chimney with a flashlight on both ends to see what type of creosote has accumulated. If you have been burning dry wood at proper temperatures and maintaining your chimney, the creosote should be a simple powdery black residue on the sides of the chimney pipe.

If the accumulation on the chimney wall appears to be either large flakes, or, even worse, a tar-like substance, then you have stage-two or stage-three creosote build-up and your chimney will require a cleaning by a professional before you use the stove or fireplace.

Assuming you are dealing with the more common stage-one powdery creosote, the next step is to acquire the brushes needed to scrape the sides of your chimney and release the creosote from the chimney walls. You will need to measure the interior dimension of your chimney and purchase a properly shaped brush that fits snugly inside the chimney pipe as well as a set of jointed fiberglass rods that allow you to move the brush up and down the entire length of the chimney. If you have a modern stainless steel chimney pipe it is recommended that you use a plastic brush--the metal brushes should only be used on traditional black pipe or ceramic chimneys. Many local hardware stores in the area stock these tools, but if you can't find what you need locally, you may want to purchase tools from a reputable online company such as Woodland Direct.

Next you need to plan an exit strategy for the creosote. This is entirely dependent on your installation, so you will have to imagine the cloud of very black creosote coming down the chimney to the top of the stove and figure out how you are going to trap it for disposal. On my simple old-fashioned wood stove

I leave the stove attached to the pipe during cleaning and then unhook the pipe from the stove later to vacuum out the creosote that falls down inside. For our modern fireplace insert (with aluminum sleeve inside the chimney) there is no direct access to the chimney pipe and I have to access the swept-out pile of creosote by temporarily moving aside the combustion baffle at the top of the combustion chamber and inserting a vacuum hose. Some folks simply detach the chimney pipe for the stove and cover the end with a garbage bag for easy removal.

You may have to experiment a little but be forewarned that the creosote powder that will be falling down while the chimney is being brushed is very black and sticks to everything-you will be getting dirty!

To begin the creosote removal you will need to remove the cap on your chimney. If you do not have a cap you may want to consider installing one afterwards to block the rain and the critters from entering your chimney pipe. Attach one section of rod to your brush, insert it into the chimney pipe and begin sweeping the brush up and down a few times. Keep attaching additional rods and sweeping up and down proceeding down the chimney until you reach the bottom.

Then reverse the process by withdrawing the brush while still brushing up and down. Inspect your work with a flashlight and if the sides of the chimney look relatively free of creosote, you can replace the cap and move inside for the final cleanup and inspection.

Somewhere down below you will have a pile of creosote which needs to be removed. Sometimes this requires detaching the stove from the pipe and vacuuming out the pile of creosote. In modern clean-burning stoves with catalytic converters or special combustion baffles, it may take a bit of hunting and studying your owner's manual to figure out how to access the pile of creosote sweepings.

This is also a good time to inspect some of the components of the stove to make sure they are ready for the wood-burning season ahead. If you have a catalytic converter, it is a good time to inspect it. If your chimney is constructed using old-fashioned black pipe, you should inspect the condition of the pipe since creosote is very acidic and will eventually eat through the pipe. Most wood stoves have a lining of firebrick and every few years these need to be replaced if they are broken or cracked.

You should also check the condition of the gaskets around the various stove doors. Finally, once the chimney and stove are back in place, it is important to make sure everything is fastened securely back together-it is quite unnerving to have the chimney detach itself while there is wood burning in the stove.

If you have an accessible roof and a simple pipe for a chimney, you should be able to do a proper chimney cleaning in approximately one hour. If you get stuck on any particular step there are lots of resources online to help you figure it out.

The most important thing is to make sure your wood burning chimney gets cleaned properly on an annual basis and that you keep personal safety in mind if your are undertaking this task yourself. As we have said multiple times throughout this article, this may be a task that is best left to a professional if you are at all uncomfortable or unsure of any of the steps described above.

Good luck. Stay safe.