Dangers of Creosote In Wood Stoves

Let’s discuss creosote in wood stoves…
In this post, we will discuss what creosote is, the potential dangers and how to prevent it.

If you are burning wood in your home you need to read this article to understand what it means if you have a buildup of creosote and what to do about it before it becomes a safety issue.

What is creosote and where does it come from?

Creosote is a by-product of poor combustion, unburned wood particles, and condensed flue gases deposit on the inside of the chimney.

There are three stages of creosote:
– Stage 3 creosote is a dripping, tarlike substance
– Stage 2 is flakier, and finally
– Stage 1 is lighter in colour, and more like coffee grounds in consistency.
Stage 3 is the most flammable and dangerous to your home.

Dangers of creosote

Creosote is highly flammable. This carbon-based condensation builds up on the interior surface of your chimney which begins to restrict the flow of flue gases and causes more creosote to build up. Tarlike creosote is a product of incomplete combustion, as the smoke hits cooler areas of the chimney it condensates and starts to build up creosote. This creosote can lead to a plugged chimney which will bring the smoke and flue gases into your home. Even a buildup of ¼” can be enough to ignite a dangerous, roaring chimney fire as this by-product is extremely flammable. Creosote can also give off an unpleasant odour in your home.

Prevention Measures

There are six ways to prevent this build up in your wood burning chimney, whether it is stainless steel or a masonry chimney.

First of all, make sure that your firewood is dry and seasoned. You can buy moisture meters to test your firewood. The ideal moisture content of firewood is 15-20%. If your firewood has too much moisture, it will turn into steam which is then drawn up the chimney and stick to the inside walls forming creosote. It only takes a few days to build up enough creosote to sustain a chimney fire!
High-efficiency wood stoves or inserts will also help prevent buildup if used properly. High-efficiency stoves are designed to burn the smoke and gases in the firebox giving you more heat for your money. Look at your chimney when burning one of these stoves and you will notice that there is no smoke coming out, just a heat vapour!
Always have a hot fire first thing in the morning. If you have a pipe thermometer, you will want to get your temperature up to 900 -1000 degrees Fahrenheit. The hot fire warms the chimney quickly creating a strong draft and also burns any creosote that may have built up overnight when you have slowed the stove down for that overnight fire.
When reloading your wood stove always give it full air for at least 15 minutes before slowing down your air control. Smoldering fires are less efficient and generate more smoke which cools on the walls of the chimney and condensates creating creosote.
The Chimney flue size should be the same size as your appliance. If you have a masonry chimney typically they are square or rectangular. These corners can be cool, and then smoke has more surface area to condensate. It is a good idea to install a stainless steel liner inside as this will improve the draft and also reduce buildup. If you have an oversized steel chimney, this will slow the smoke down and again create more chance of condensation inside.
There are also products that you can buy to turn that glazed creosote into a powdery substance that is easier to clean.

How do I get rid of creosote?

You have probably heard of the chimney sweeping logs!

NOTE: These do not clean your chimney! But they will help in turning the glazed creosote into a sweepable form of creosote.

We recommend a product called ACS.

ACS is a product that you can spray directly on your firewood or into a low burning fire.
The heat of the fire activates it and carries it up the chimney to attack the creosote.
As the chemicals penetrate the sticky tar-like creosote, it turns it into a loose powdery non-adhering ash that can easily be brushed away.

ACS is safe for all types of wood burning appliances even catalytic stoves. Weekly usage will reduce your risk of a chimney fire.

In Conclusion

So to conclude:

make sure your fuel is nice and dry,
use your appliance as recommended by the manufacturer,
have a hot fire every day and make sure you get your chimney swept at least once a year.

We recommend in your first year of wood burning to get your chimney swept twice. The chimney sweep can tell you if you are creating an abundance of sticky, tarlike creosote or the loose powdery sort. Then you can make adjustments in your burn techniques if necessary or utilize a product that will reduce the flammability of the creosote. Our chimney sweeps are professional and have a wealth of knowledge, give us a call to book your appointment today!

The Original Flame is a full-service boutique shop providing you the perfect fireplace where warmth and style meet. Visit us for the full service treatment, from purchase to installation and ongoing service and maintenance.

Submitted by The Original Flame