Do Chimney Cleaning Logs Work – National Agency Speaks Out

You may have been told by friends that they avoid paying to have their chimneys professional cleaner since they use chimney cleaning logs after 40-50 fires. Does this process remove all the creosote that can be within a chimney?

Do chimney cleaning logs work? Chimney cleaning logs do not work to prevent chimney fires. They contain active minerals that will dry out the creosote that is built up in the chimney. The creosote will become brittle and will only become less flammable.

According to the Chimney Safety Institute of America, chimney cleaning logs will not eliminate all the creosote buildup within a chimney. They will help to chemically breakdown the creosote that is present within the flue. Once the creosote is no longer sticky, it could begin to fall out of the chimney on its own.

Nevertheless, to remove most of the creosote that has been changed in composition by a chimney cleaning log, you need to contact a professional chimney cleaner to service your chimney. The creosote will have been dried out by the minerals that are contained in the typical chimney cleaning log, but most of the buildup will remain.

Using chimney cleaning logs between professional chimney cleaning sessions is advisable. It will reduce the rate of accumulation of creosote. The question that you might have is should you use them more often than is recommended by the manufacturers?

How Often Should I Burn a Creosote Log?

You should burn a creosote log after 40 fires. If you use green firewood in your fireplace daily, you should use a creosote log more often since there will be more creosote present. If you have not used one of the chimney cleaning logs for an extended period, burn three of them, one after the other.

According to the creosote log manufacturer Pine Mountain Fire, you need to use their product after every 40-60, or every season if you rarely use your fireplace. Their specialized powder that is contained in their creosote fire log is converted into a gas that gets absorbed by the creosote that is present. The creosote will dry out and will start to flake. I recommend the Pine Mountain Creosote Buster that is available on Amazon. Click here for current pricing.

The flaking of the creosote will make it easier for your professional fireplace cleaner to remove the creosote. If you do not use the creosote removed log often enough, the buildup will harder for a chimney sweep to deal with.

This type of log that needed to be often after at least forty fires, has been approved by the Chimney Institute of America. Nevertheless, if you have firewood that has not been aged 12 months, you will need to burn a creosote log after every twenty fires. Wet wood will release more creosote that will accumulate since it is quite sticky due to the sap that is within the wet wood.

If you fail to burn a creosote log after every 40 fires, the creosote will start to harden and become shiny. It will be stuck to the inside of the flue. When the creosote has reached this state, you will not be able to remove it on your by trying to brush it off. You will need to call a specialist that will need to use chemicals to break down the buildup.

Here is a table that illustrates what others have used to remove creosote from their stove pipes:

Method tried for removing creosote Percentage of total results
wire brush42%
knife blade26%
water soaking sections of the pipe23%
anti-creosote spray (click here)9%
data derived from various online household tips forums

Are Chimney Cleaning Logs Safe?

Chimney cleaning logs are safe if you follow the manufacturer’s instructions correctly. If you do not use them in conjunction with a seasonal professional chimney sweeper, there is a chance that a fire will occur even if you use the chimney cleaning logs correctly.

The Lord Chimney division of Lords Services LLC that services the Houston, Texas area, states that you should assume that using chimney cleaning logs can replace regular professionally down chimney sweeps. The logs will help to break down only the initial stages of creosote buildup within the flue. The logs will change the chemical composition of the creosote and cause it to fall out of the flue into the bottom of the fireplace where it can be safely swept away.

This concept is airtight only if the flue is straight. The problem is that most flues are not completely vertical, especially in older homes. If soot can drift and sit on the edge of a small angle of a flue, an accumulation will occur.

The minerals that are within a chimney cleaning log will cause the creosote to dry and then flake. It will drift downwards and lodge on the edge of a crooked flue. Here is what can occur if the remnants of creosote accumulate in the bends of the chimney.

  1. The chimney will become blocked. The toxic fumes from burning wood will then become trapped and enter your home. Venting in a chimney is crucial and should be compromised. Also, this type of blockage is hard to completely remove since the flue is not straight. A professional chimney sweeper will charge more than usual to get rid of this accumulation that was caused by the burning of creosote cleaning logs.
  2. There is higher risk of fire in a flue that has an accumulation of flaky creosote. You start to notice that numerous embers and sparks are flowing up your flue.
  3. The smoke shelf that is above the firebox area in a fireplace will accumulate flakes of dried out creosote. The job of a professional chimney sweeper with then become hindered since this area is the most difficult spot to reach in a chimney. Again, the risk of fire becomes higher.

You may feel that there is a way to get rid of the excess dry creosote on your own by burning a hotter fire. I will explore whether this is true.

Will a Hot Fire Remove Creosote?

A hot fire will not remove creosote. There are different degrees of creosote. The third degree is hard, glass-like, and flammable. A hot fire in a fireplace that has solid creosote will simply cause a chimney fire.

Russ Dimmitt, the Director of Education for CSIA, states that burning out later stages of creosote is dangerous. An earlier stage of creosote can be burnt out, but the later deposits that are hard cannot be burnt out safely.

Even a new stage of creosote that is too thick is not easily removed by burning out the chimney at a higher temperature. If you notice that the creosote is 8 inches thick, you need a professional to remove it and then to sweep out the debris that is caused so that the risk of fire is lowered.

Another reason to hire a professional chimney cleaner is that a chimney is not designed to be burnt out. The firebox is the only area that is strong enough to deal with a hot temperature. The lining of the flue is set up so that the heat and ashes can rise out of the chimney in a safe manner. Allowing flames to shoot up into the flue by burning a super-hot fire is just asking for trouble.

Also, besides having a lining that is designed to route smoke, the material used to build some flues is flawed. Masonry chimneys in some cases do not have adequate air flow between the masonry and the surrounding combustibles, making the risk of fire due to elevated temperatures much higher.

Besides having a lack of air flow at times causing problems with high heat, the brick and mortar itself will ignite at lower temperatures just over time. Weather and exposure to gases from numerous fires will cause the mortar between the bricks to deteriorate.

Since the brick and mortar is exposed to temperatures at around 2100 degrees, the expansion and contraction of the brick will cause it to become brittle. Also, with a metal flue, setting a hot fire to burn out the chimney will cause the metal to warp and to pull away from its surrounding materials. In other words, the air flow between the metal and chimney material will be altered causing even further problems.

Can you Burn Wood with a Creosote Log?

You cannot burn wood with a creosote log because it will reduce the effectiveness of the minerals contained in the creosote log. Creosote logs work better if they are not hindered by the humidity that is caused by burning wood at the same time.

According to FEMA, if you were to burn unseasoned wood, creosote will be released. The creosote that is in the air will mix with the smoke that is created with a creosote log. The minerals that need to be unaltered are changed by the addition of the sticky film that has been turned into a gaseous substance. In other words, burning wood along with a creosote log is counterproductive.

Another reason to avoid burning a creosote log along with wood is that the temperature will become too high. A creosote log will not release the right consistency of its minerals if the fire is too hot. However, it is recommended to light a fire before adding a creosote log. You will need to let the fire burn down beforehand. A creosote log should only be placed on the hot ambers of a fire so that it will light up easily.

Since some manufacturers suggest burning a creosote log just once a season, what happens if you had purchase numerous creosote logs at the same time? How long will they last? I recommend the brand Creosote Sweeping Log that is available on Click here to have your Creosote Sweeping Log delivered to your front door.

Do Creosote Logs Expire?

Creosote logs do not expire since they are well-sealed and contain ingredients that do not break down over time. Do not remove the packaging of your creosote log until you are ready to use it. If the air around it is humid, it will negatively affect it after a lengthy period.

The company Eurexim Securiflame, lists the components that are contained in their creosote sweeping log. The main components are slack wax and wood sawdust. These components will not expire.

Nevertheless, it is best not to expose the creosote logs to the air due to these components. The slack wax is used to hold together the wood sawdust that the log will be able to hold its shape but allowing the logs to sit in a moist area over a prolonged period could reduce the release of the minerals. The minerals are what cause the creosote to dry out and to flake.

Also, their creosote sweeping logs contain many minerals:

  1. Urea
  2. Anhydrous Sodium Sulphate
  3. Zinc Chloride
  4. Amorphous Silica
  5. Phosphorus Pentoxide

Since minerals cannot be degraded by heat or air, they will remain stable and will not expire.

How Long Does It Take a Creosote Log to Burn?

It takes a creosote log 90 minutes to burn. A creosote log is mostly wood sawdust and slack wax. The slack wax causes the sawdust to burn at a slower rate. 90 minutes of burning is needed to release the correct level of minerals to break down the accumulated creosote.

According to Joseph Enterprises, Inc., in San Francisco, California, a creosote log will burn completely after around an hour and a half. After the log has turned into ambers, the minerals are still working their way into the deposits of creosote that are in the flue. The minerals were carried by the smoke that was created by the burning creosote log.

The process of the absorption of the minerals into the hardened creosote takes a few hours even after the fireplace is cooling down. Then, over the next few weeks, the drying out of the creosote takes place. The dried-out creosote then turns into a flaky papery substance that will begin to pull away from the lining of the flue.

It is advisable to burn small fires over the next few weeks after your treatment with a creosote log. This will cause more of the brittle creosote to fall into the fireplace.

Even though the burning process seems short, there is no reason to feel that you need to burn more creosote logs, one after the other. Just by burning one you will start the cycle that breaks down the creosote.

Aron Blake

I am the lead copywriter on Homezesty and the Webmaster. I have a lot of experience in home renovations and the creation of style. I enjoy writing and sharing my tips on how to create the best living environment. My Linkedin Profile, My Twitter Account

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