Wood Acclimation

Article - March 31, 2008

This week’s question comes from Robert. He writes:

“I live on an island in Hawaii (surrounded by water of course) where the humidity is always high and it rains a lot. All the material that I’ve been reading says to dry your wood to about 6% before working on it. Then you leave it in your shop for several days to let it become equal to your humidity. My humidity is always super high. A lot of times in the 80’s and above. Do I still dry my wood to this dryness (6%) even though it will probably go up to 12 to 14 % after acclimated to my place (I do my work in a garage that is open on two sides)? Do I store my wood here in the open garage or somewhere else? What % humidity should I be working on my wood? BTW, the items will probably stay here in Hawaii and we don’t use heating and not a lot of us use air conditioning in their homes. So I believe the humidity inside and out are pretty similar. And it rains a lot here. Sometimes 3 to 5 times a week. I’ve seen charts that show the moisture in wood left on its own here will have between 11 and 14% moisture content throughout the whole year.”

And here was my reply:
“If you are buying kiln dried wood, it will most likely be shipped in at around 6-8%. But if it sits in a lumber yard for a while, you can count on the moisture content going higher and higher every day, until it reaches equilibrium with the environment. So by the time you get it, it is probably up in that higher range anyway. And just like in anyone else’s shop anywhere in the world, you want to let those boards acclimate to your shop’s conditions. And if there is a lot of humidity, your boards will have a higher than average moisture content. Remember that humidity is not necessarily our enemy. CHANGES is humidity are the real problem. So if its relatively constant inside and outside, you should have no problems working with wood that has as higher than average moisture content. Probably not a bad idea to get a moisture meter so you can monitor theses things and figure out just what percentage these boards get to and how they change over the course of the year. But it sounds like you already have a head start on the research. You are wise to be cautious. But I think your actual workflow will not be all that different from anyone else’s.”

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