Tar in the chimney
Complaints about poor heat output from wood burning stoves are usually due to burning unseasoned wood.
Unseasoned wood contains high levels of moisture, around 33% – 65% water by weight. It takes a lot of energy to boil the water in a wet log and send it as steam up the chimney. Therefore, it is essential to dry or ‘season’ wood before it is used as fuel.
For open fires, burn hardwoods (deciduous trees). Softwood (coniferous) is suitable for kindling and in closed stoves as it spits alot. As a general rule, no wood should be burnt until it is seasoned for at least a year.
A problem with burning wood is the production of tar. Wood tar is highly flammable, one spark from the fire below can ignite a build up of tar leading to a chimney fire. Tar can also be corrosive, potentially damaging flue liners. Burning unseasoned wood makes the situation worse, as the excess moisture cools the fire and adds to the condensation in the chimney, mixing with the tar to produce a brown creosote which then runs down the chimney, drips out round the stove pipe joints making a mess with a pungent smell.
This is an example of tar in a lined chimney due to burning damp wood
You can purchase a moisture meter, this gives you a digital reading of the exact moisture content of the wood you want to burn.
If you can smell smoke in another room or loft space
If when you light your fire you can then smell fumes in another room or in the loft space, this means that the mid feathers (the bricks that divide the chimneys) have deteriorated.
The chimney will need to be lined before it can be used again. We carry out chimney lining for wood/multi fuel stoves, open fires and gas fires.
Problems in Chimneys
We were called out to remove tiny polystyrene balls from a chimney with a gas fire.
This is a view up the chimney showing just how much there was inside the chimney.
The Chimney is clear and the gas fire has been refitted.
20 bags of polystyrene balls were eventually removed from they chimney.