When we talk about chimneys and chimney sweeping, we often talk about creosote. But what exactly is creosote? What habits should you adopt to keep it to a minimum in your chimney?
Creosote is a deposit left by smoke. It is caused by incomplete combustion of the wood or by bad combustion of the wood. It sticks to the chimney wall. Creosote can be found in three different forms.
In the first stage: Dust that many call soot. At this stage, creosote is easy to remove because it is soft.
In the second stage: Creosote condenses. It becomes very hard and shiny. At this stage, simple brushing is not enough to get rid of it. A drill with a brush attached is necessary to remove it.
In the third stage: The creosote is now vitrified and is extremely flammable. This is usually the point at which chimney fires occur. Regular sweeping will ensure that you never get to this point. Creosote is a risk to you and your family. When burning fuel such as wood, pellets or heating oil, it is inevitable that creosote will accumulate in the chimney. However, there are certain practices that can be used to prevent excessive creosote build-up.
How to reduce creosote build-up
Use dry wood
The moisture content of wood is your worst enemy. Wood should not contain more than 20% moisture. Buy your wood in the spring. The wood should be split small enough to dry properly. If you have an efficient heating system, pieces of wood up to 6 inches in diameter do not need to be split. For less efficient systems, ask your supplier to split pieces larger than 3 inches in diameter. Store the wood outside and where there is the most sun on your property. Cover only the top of the cord and leave enough space between each row.
Limit the use of softwood
Softwood creates more creosote than hardwood. It is acceptable to use it for fire starting and stoking in the spring and fall, but it is not recommended for year-round use.
For efficient combustion, the fire needs enough air. When you start your fire, leave the door slightly open. For obvious safety reasons, stay close to the fire at this stage. Once the fire has started, it is also important that there is enough air. Don't close the air intakes too tightly. If the fire seems to want to smother, there is not enough air.
Unless you build your house, you have little control over this factor, but be aware that a chimney that is inside the house rather than outside heats up more quickly and cools down more slowly. A cold chimney encourages creosote build-up.
Heating system efficiency
High efficiency heating systems allow for better combustion of wood and gases. As a general rule, the newer your heating system is, the more efficient it will be and the better it will burn. You will also be less likely to have a chimney fire due to creosote build-up.
When safety and economy go hand in hand
Taking the necessary actions to prevent excessive creosote build-up in your chimney takes effort. But you will be rewarded with the knowledge that you have done what is necessary to keep your home free of flames. Plus, better wood burning means savings.