What are Logs?

Wood log boilers generally burn virgin wood which has been cut and processed into logs. Other clean waste woods such as carpentry offcuts are also suitable. Several questions and important factors when producing or buying your wood, including storage and handling. 

Whether buying or processing your wood logs the most critical factor is the wood must be dry. By dry, we mean less than 20% moisture and ideally less than 15%. 


 

Nature will dry wood if it is correctly stored

Wood will naturally dry in the UK, a little slower in wetter Northern areas but it will still dry to be fuel. 
How long this takes depends on the wood itself and the way it has been processed and stored.
Wood is ready to be burnt after about 2 years of being stored in suitable conditions and split during the early summer of use. By two years we generally mean two full spring and summer periods. If however the wood is split and well stored in the first winter it’s possible to be ready the following winter depending on the wood type. 
Splitting wood opens the internal surfaces to allow interior moisture to escape through the action of the wind and sun. It also increases the surface area, allowing quicker drying.

The way it is stored is very important

The best way to dry wood is to keep it off the ground with a ventilated floor such as a pallet. The top is covered in a waterproof cover ideally black in colour to heat up from the sun and in an open position where the wind can do the most benefit.

 

When it rains, roads become wet. They soon dry when exposed to the sun and wind. If shaded or in sheltered spots, it can take days to dry.

It is the same if you store wood in an enclosed building such as a closed garage. Store your fuel outside covered from most of the driving rain and off the floor.

log store

Wood should be split

The density of the wood changes the time it takes to dry. The tighter the grain structure inside the wood, the longer the wood takes to dry. The moisture exits the wood via these grain lines the natural tubes within the wood: the smaller these tubes, the more challenging to expel the water. 
Oak and other hardwoods have small moisture tubes while pine and most softwoods have larger rings which allow water to escape faster. 

 

  • Splitting wood speeds up the drying time. 
  • Splitting into smaller logs, wood dries even faster. 
  • Wood split for kindling dries very quickly.

Rule of Thumb

  • 6” log in the round fresh, contains around approx 1 pint of water .
  • Split it can be dry enough to burn in under 1 year if well stored.

 

The benefits

  • Simple to operate and ignite

  • Burns logs and clean wood waste

  • Correctly sized once or twice per day fuelling

  • Located in a boiler room simplifies cleaning and maintenance

  • Very high efficiency up to 92% depending on model

  • Wood logs can be stored locally to the boiler house

  • The boiler house can be located remotely to the property to be heated

  • Can be easily linked with an alternative heating source

The check list

  • Requires a dedicated boiler room capable of fitting the boiler and accumulator

  • Requires daily fuelling

  • Fuelling is undertaken by hand

  • Requires occasional ash removal

  • Requires annual maintenance by engineer

 
Birch logs