For an orderly site and ultimate matching of pattern, boards should be stacked consecutively off the log from which they have come. Ideally, stacks would be on a level concrete base, in an airy shelter. This keeps off not just rain, but also sun, which can cause extra splitting and warping if protection is not given. If no overhead shelter is available, logs are best stored in a North/South direction, ideally with a cover on the Southern side. Timber should not be seasoned in closed airless conditions, which will encourage fungi and stain in the timber, as well as being slow to dry. Sufficient, but not excessive, ventilation around the boards is what is aimed for.
The traditional rule for timing has been one year per inch of thickness, plus a year. However, use of a dehumidifier will shorten this. For boards up to one and a eighth inches thick, one full “normal” dry season, including the latter drying months of August and September is sufficient. Thickness, temperature and ventilation are the crucial ingredients.
A few timbers are prone to fungal staining due to insufficient ventilation around the stick area, leaving lines across the grain. This can go quite deep into the timber. Sycamore, especially where it is valued for its pure whiteness, should be seasoned vertically, with only one spacer between boards at the top.
Bearers at the bottom of the stack should be wide for stability, and thick enough to get sufficient ventilation under the first board. They should be spaced according to where the subsequent spacer sticks will be positioned. They should be set exactly flat and level down the length so that the boards do not season curved.
Sticks should be of exact equal thickness between each board, about 1 inch thick. Unequal thickness will lead to curved boards above. Distance between sticks depends on the thickness of the boards, but the aim is to have no sagging between sticks. A guide would be 18” distance between sticks for half inch boards, 20” distance for 1” boards, 25” distance for 2” boards and 28” distance for 3” boards. Sticks should be lined up exactly vertically above each other. If they are out of place, this will lead to weight from boards above creating localised pressure on a lower board where a stick is out of place.
Boards should be protected from direct sun and wind to slow down the rate of moisture loss. Paint and/or even metal bands can help avoid ends splitting. The log’s own cap helps to protect the top board from surface checking. Alternatively, if some sheets of e.g. corrugated iron were available, these could be put over the top of the stack, and secured with cord. Extending the end of the sheet on the South side keeps the sun off the most exposed end.
If it is intended to keep timber stacks in a particular area as a longer term activity, it is worth bearing in mind that sapwood is very attractive to wood boring beetles. This is great for beetles, and birds. It is the timber yard equivalent of standing deadwood in the woodland, doing its bit to increase biodiversity. But in more attractive timbers, they progress into the heartwood and ruin the timber. A site can become infected over time where boards are constantly brought in and are seasoning next to older boards. This can be expected and ignored, or other steps can be taken. For example:
* Having a regular clear out or high turnover of the whole stock
* Ensuring spacers, where reused, are not infected
* Cutting off the sapwood prior to stacking
* Use of preservative on the boards. Not really recommended. The timber will subsequently be worked, with the potential for harm due to inhaling toxic dust.
For drying the timber suitable for furniture and joinery making, building a
box is an inexpensive investment.