Air Drying Lumber

rough sawn lumber sticker stack

Freshly milled, or green lumber has a high water content. For some uses, this is OK, but if the wood is going to be used indoors most of that water will need to be removed.

Fortunately, getting rid of the water is not difficult. It evaporates. For both lumber and laundry, the process is called drying. In either case, there are two options: quick drying in a heated appliance (called a kiln in the case of lumber) or air drying outdoors. Air drying takes longer, of course, but requires no energy other than what we get for free from the sun and the wind. So, there's both a cost savings and an ecological benefit to this approach. In most cases, the end product will be pretty much the same either way.

Air drying requires good air circulation. In the case of lumber, this means that stacks need to be built in a way that allows air to move freely around the individual boards and carry the moisture away. This is done by stacking boards in layers separated by spacers called stickers.

Lumber should be sticker-stacked soon after milling, within a few days in most cases. Failure to do so may result in staining of the lumber which is caused by microorganisms or chemical reactions in the wood.

There's no shortage of information available about how to properly build a stickered stack of lumber for air drying. Rather than trying to summarize it here, there are links below that you can follow to read and listen to people who know what they're talking about. Of course, they sometimes disagree with each other on the details...

As several of these resources point out, air drying outdoors will not dry lumber quite enough for indoor use. To complete the process, simply bring lumber into a heated space for a time.

If you don't have a moisture meter to measure the moisture content of your lumber, you can use the oven in your kitchen and an accurate scale instead. The technique is described in detail on page 14 of the Air Drying of Lumber publication.

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