Seasoning Firewood

One of the most common complaints new wood burners have is that their wood is not burning well. Seasoning firewood is a vital first step before your wood reaches the stove and when done well can make tending your fire and heating your home a dream. Done badly you are setting yourself up for, at best, frustration and, at worst, a chimney fire.

When freshly cut, firewood has a very high moisture content (between 40% and 60%) which can cause all sorts of problems when it come time to burn it. Wet wood is hard to light, smokey when burning, can contribute to creosote build up in chimneys and is heavy to handle.

Seasoning firewood reduces the moisture content dramatically (down to 15% to 20% by weight) and turns any cut timber into first class fuel for your wood stove.

How to season firewood

The principals of seasoning firewood are very simple - get your wood split to size and stacked off the ground and exposed to the wind and sun for as long as possible. Firewood dries out very slowly because the moisture is trapped deep in the wood, so planning ahead is essential.

  • time - to allow the moisture locked in the centre of the log to evaporate. 18 months to 3 years or more is ideal. 12 months minimum.
  • wind - nothing dries clothes or firewood faster than exposure to strong winds
  • protection from rain - rain wets the surface and slows down the process of seasoning firewood
  • exposure to sunshine -the heat speeds up drying, even into winter

Planning ahead

Estimates of the heating needs of a typical home, doing all of its winter space heating with wood run between 3 and 5 cords of firewood per heating season. This obviously depends on many individual factors such as how well insulated your home is, how efficient your stoves are, how warm you run your home and how severe your winters are. If you are planning for your first winter heating with firewood plan to get at least 3 cords worth.

To allow time for seasoning firewood properly you need to cut or buy in your firewood supplies 12 months or more before you intend to burn it. In practice this means buying your firewood in the autumn, or winter, for the following winter. Some people season firewood for up to 3 years - cutting firewood years in advance. This requires more space as you have to stack more firewood on your property, but is no more work in terms of handling the logs. If you have the time and space to season your wood for longer you may be able to buy cheaper firewood sold "unseasoned" when demand is low.

Before you buy firewood you need to plan for where it will be stacked while it seasons - depending on your climate this may be in the open, or in a covered but open sided log shed. Check out our pages on firewood storage and firewood racks for some more ideas.

Splitting logs

Firewood dries and burns much more efficiently if it is split into smaller pieces very soon after it is cut. Smaller pieces of firewood have a larger surface area through which to dry so your logs can go from 'unburnably wet' to 'passably dry' much more rapidly.

In recent years we have begun splitting our logs into smaller pieces - small pieces make maintaining a balanced fire in your stove easier. If one of your logs practically fills your wood stove, then putting that log on will damp down the fire until the log catches. During which time the fire will burn with a smokey and polluting flame. These big logs can only be loaded one at a time so you need to wait ages before there is space for the next, during which time the fire may have cooled down again.

Contrast this to more regular feeding of smaller pieces, where the fire stays hot and efficient throughout - you trade slightly more effort loading the stove for a cleaner and easier to manage burn.

In practice it can be useful to have a mix of sizes - the large, mis-shapen log can be great for loading on the fire right at the end of the evening. You may not keep the fire in until morning, but you will get a longer, more even heat throughout the night.

Stacking firewood

A home made seasoning rack with a couple of weeks worth of wood.

There are many ways to stack firewood so that it seasons - infact it is very hard to actually do it 'wrong' and end up with unburnable wood. However, seasoning firewood can be faster with some methods and others are better suited to particular climates.

In general you want a tight and neat stack which is long, tall and narrow so that the firewood is well exposed to the wind and sun. If winters in your location tend to be wet, as opposed to months of settled snow you will need to rig up some kind of rain shelter during the winter months. This may be as sophisticated as a dedicated wood shed or a simple tarpaulin thrown over an otherwise exposed stack. Check out our page on how to stack firewood for some neat ideas to make stable stacks and even works of art from your wood pile.

Once your firewood is split and stacked allow time and the elements to do their job - come back the following winter for the best firewood you've burnt in years.

Finishing the job...

One last seasoning stage which some people like to include is the simple step of bringing your firewood inside a few days before you intend to burn it. This lets the logs come up to room temperature and any surface moisture, from rain or snow, dries off.

Leaving logs near the stove helps this last stage of drying but does very little to improve "green" wood with a high moisture content in the fibres (as opposed to a bit of damp on the surface)

At home we have some baskets and a steel log hoop, which hold together enough firewood for 5 days or so. Plenty to see you through a spell of bad weather without needing to collect more.

How to tell if wood is seasoned?

Preparing wood to burn in a few years time is great, but doesn't help if you need to burn wood now. To tell if your wood is dry and ready you could try:

  • lift a log - dry logs of the same type of wood as substantially less heavy than freshly cut
  • knock some logs together and listen to the sound - green logs make a heavy "thud" while well seasoned logs almost "ring"
  • examine the end grain of the wood - depending on the type of wood small radial "checks" may appear as the wood dries and shrinks
  • finally - you can get small hand held moisture probes that you can put against a log to measure moisture content. These are the only way of accurately measuring the quantity of water in a log

As you get more experienced with handling wood you'll eventually be able to tell by feel if a log is ready.