wood air drying estimates

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Forum topic by Spikes posted 09-30-2018 04:41 PM 689 views 0 times favorited 5 replies Add to Favorites Watch
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125 posts in 927 days

09-30-2018 04:41 PM


newbie here with very little access to lumber and trying to figure out if it’s feasible to dry wood at home.

Most of what I can get my hands on at low price is green wood, especially doug-fir. As I understand it, indoor furniture should be built with moisture content of around 7%. I’m trying to figure out if it makes sense for me to dry wood at home. Also I’ve read that kiln drying can lead to a lot more cracking than air drying and indeed my experience trying to buy kiln dried pine was not a good one.

With that in mind, I did some research and found this PDF with lots of tables on air drying time based on wood, location and time of the year:

that seems to contradict the rule of thumb I’ve seen of “1inch a year”, for example for doug-fir in CA in summer air drying time to 20% can be as little as 10 days so to get down to 7% it seems reasonable to guess estimate something like a month+.

Can anybody point from experience if these numbers are even remotely close to reality? it really makes no sense for me to try to dry at home if I have to sit on the wood for 6 months before I can use it, but a month or so, doing most of the drying in summer, would definitely be acceptable.

Also in terms of expenses, it seems the biggest costs are energy to run a fan and a dehumidifier and the fan and dehumidifier themselves. Plus a humidity meter, so maybe around $200 or so.

In terms of how hard it is to do it right… most threads I’ve read talks about proper stickering, wood rotation, sealing the ends and that’s about it. Then in one thread a guy tossed out a book name and from that it seems that to properly dry wood you need a phd… maybe the truth is something in between? if someone has dried big chunks of wood before I’d love to hear your experience. Most of what I found was related to drying small chunks for turning, not 1×5x8’ kind of thing.



-- Don't worry about making progress, worry about practicing. If you practice you will make progress even if you don't want to.

5 replies so far

View Gene Howe's profile

Gene Howe

12258 posts in 4310 days

#1 posted 09-30-2018 05:04 PM

My experience with green Doug fir is that you’ll need proper stickering, lots of weight to help prevent warps and twists and, sealed ends. I’m in AZ and, I’d recommend 90 days minimum for 1” thick soft wood. A fan to circulate the air…just a small table fan or, a cheap box fan is good. Keep checking the MC about every 30 days.

-- Gene 'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton

View HerbC's profile


1808 posts in 3741 days

#2 posted 09-30-2018 05:16 PM

First of all, the “one year per inch of thickness” drying “rule” is a rather inaccurate generalization. Most green lumber will air dry much quicker than that.

In most climates, air dried lumber will not reach 7% when dried outside. Generally it will stabilize somewhere in the mid to low teens.

Once the air dried lumber has stopped “drying” outside you can often dry it further by moving into a conditioned space where the ambient relative humidity is lower than the outdoor RH and leaving it inside to drop more moisture.

Proper stacking (including the use of adequate number and sized stickers) is critical to producing useable quality lumber. Good airflow through the stacked lumber is also usually important (but some species don’t do well if dried too fast, white oak being one example.)

Good Luck!


-- Herb, Florida - Here's why I close most messages with "Be Careful!"

View Aj2's profile


3414 posts in 2680 days

#3 posted 09-30-2018 05:29 PM

I think you should stay away from air dried Dfir. If the pitch isn’t set well in a kiln you see it weeping if the temp get up enough. There might be some projects to use it on I just think of any right now.
If your out here on the west coast like look for Ash, oak or Alder yes I said alder.
Try some air drying see what happens doing is learning.
I’ve experimented with lots of woods some were complete failures some not. But I still gained knowledge

-- Aj

View KuhShise's profile


12 posts in 813 days

#4 posted 10-01-2018 12:47 AM

Like most others on this page, we are in various places on the learning curve. Most of my experience has been without the benefit of a moisture meter until recently. As my profile references, the past 8 years have been spent (mostly) working with White Pine paneling. I have done some other projects using Cherry, Birch Maple, Red Oak, Spruce, Catalpa and Hemlock; mostly on specialty items. Recently I sprung for a pretty good moisture meter and have been surprised by the readings on some things I thought were quite dry. Initially I followed the recommendations of my local saw mill operator concerning the need for kiln drying and acclimating of paneling prior to final finishing and hanging in the house. I thought that the lumber I was processing in my shop was in the 8% range, but the new meter has shown the pine in the shop is closer to 10%. Despite the fact that the heat is from a separated combustion gas ceiling heater. (Closed loop combustion with the outside combustion air being blown into the unit and all burned gas and moisture exhausted to the outdoors.) The house has a geothermal heating system with basement heated using in-floor heat in combination with continuous circulation warm air for the living spaces. Acclimating the paneling for a couple of weeks in the heated basement brings the moisture content down to about 8.5% and the paneling that has already been installed over OSB on the walls is about the same percentage. Recently we were gifted a truck load (700 bd.ft.) of Black Walnut that has been barn stored, stickered for over 50 years. I was surprised when this came up at about 11% on the meter. We stickered this on 4×4’s in the shop and in the intervening month or so it has dropped to about 9.5% and seems not to have changed in several weeks. We have had a wet summer, so some of this higher than expected moisture content may be due to outdoor dew points. It will be interesting to see what the measurements change to after Winter sets in and 20 below dew points are encountered on a regular basis.

View KuhShise's profile


12 posts in 813 days

#5 posted 10-01-2018 02:44 AM

Spikes, You and others might find this table on relative humidity vs wood moisture equilibrium percentages helpful.

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