In Germany it is forbidden by law to burn damp wood. The first ordinance for the implementation of the Immission Control Act stipulates that the moisture content of firewood may not be higher than 25 percent. Since the moisture content of freshly felled wood is around 60 percent, the fuel must first be dried. You can find out how in the following article.
Firewood should be stored in an airy, sunny but sheltered place
Why is it necessary to dry firewood?
If the wood has a high level of residual moisture, it will only burn incompletely. In this case, when it is burned, substances are produced that can damage the environment and the heating system. For example, acetic acid is increasingly formed, which, together with other combustion residues, attacks the fireplace and chimney. Since significantly more soot is deposited when burning damp wood, the stovepipes may become clogged and shiny soot may form, which can lead to a dangerous soot fire.
Last but not least, the energy yield drops to a third, since the water in the wood has to be evaporated first. In other words, the wood is drying in the oven, which unnecessarily wastes fuel and drives up costs.
How can wood be dried?
Wood drying is usually done by storing it correctly in the open air. Proper storage is also important to prevent mold and rot. It also prevents pests such as house longhorns or sapwood beetles from being able to nest.
The storage place
This should be such that no additional moisture reaches the wood. Therefore, pay attention to the following points:
- air supply: The air should also reach the back of the firewood. As a result, moisture cannot collect anywhere, which could lead to mold or rot.
- sun exposure: When the sunlight reaches the wood pile, the drying effect of storage is enhanced. The residual moisture evaporates faster.
- Protection against weather influences: The firewood should not be exposed to rain and snow, as this allows additional moisture to penetrate.
Well suited for wood drying is, for example:
- A house wall facing south or southwest. Be sure to stack the wood 15 centimeters backwards so that the back of the stack is also ventilated.
- It is ideal if the fuel is protected from above by a canopy roof.
- Alternatively, you can pile the wood up to dry in a traditional windrow, a free-standing woodpile. The special shape allows the water to drain away while the heating material is dried by the sun on nice days. An optional roof protects from the weather from above.
However, the basement or a closed garden shed is unsuitable for drying. The air exchange in rooms is far too low and the still damp wood inevitably begins to rot or mold. For the same reason, you should aim to cover the stack with a tarp.
How long does drying take?
There is no general answer to this, since the weather conditions play a major role in storage in the open air. Depending on the type of wood, the process of drying outdoors takes about two to three years. Under optimal conditions, the heating material can even be used after a year.
tips
The wood to be dried should also be protected from below against the ingress of moisture. Therefore, stack it on a surface covered by stones, Euro pallets (€29.99) or a tarpaulin made of pond liner.