Acclimating kiln dried lumber in an unconditioned space?

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Forum topic by botanist posted 03-18-2015 09:21 PM 1901 views 0 times favorited 8 replies Add to Favorites Watch
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167 posts in 4550 days

03-18-2015 09:21 PM

I’ve got a woodworking project in the works, my first using rough-sawn, kiln dried lumber (I’m doing the project late spring/early summer). The concern I have is how the wood will react going from the lumberyard, to getting milled, to going into the house as finished furniture. I plan on milling my different elements (e.g. legs, rails, slats) right before I need them and not all at once. My garage is unconditioned, so I’m wondering if I should take any special precautions while I’m storing the lumber before using it, as well as how long should I let it acclimate before I start to mill it?

8 replies so far

View Ghidrah's profile


667 posts in 2233 days

#1 posted 03-18-2015 09:42 PM

If I expected the product to be sturdy and look good for any length of time I’d rough it and let it sit for as long as possible then bring it to final dim and let it sit again where it’s going to go if possible. Then I’d mill it and assemble pronto then apply protection to minimize moisture absorption.

If your shop is in an unheated basement buy a diathermic heater to keep in the shop while it’s drying out.

If I’m going to trim an existing room, (new winds, doors and BB I go out of my way to store the stock under a bed or against the wall for a week or so. I had 1 too many joints open up on me in the past.

Rough cutting the dims opens clogged pores and allows for off gassing.

-- I meant to do that!

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Dave G

337 posts in 3059 days

#2 posted 03-19-2015 11:12 PM

What Ghidrah says.

Just for kicks I had a piece of 8/4 hard maple rough about 8” x 18” that I weighed every day using a 25# postal scale until it settled after bringing it from an unconditioned lumberyard (enclosed about 20 deg F) into my unconditioned basement (45 deg F). It took slightly less than a month. And it dried a few percent.

This movement that wood does is the single biggest factor in all of woodworking and you’re doing well to think about it.

-- Dave, New England - “We are made to persist. that's how we find out who we are.” ― Tobias Wolff

View bonesbr549's profile


1588 posts in 4078 days

#3 posted 03-20-2015 12:20 AM

My rule of thumb is if it’s coming into the shop I like to let it go as long as possible. I prefer at least a couple weeks. I also tend to take a sample piece mill it and watch it for a couple days and it will give me an idea. Now I will say that I tend to buy in bulk to maximize savings. I tend to buy in the 250-500bf range.

When I start my milling, even if its been in the shop a good while, it’s a three step process. I go from comercial, to basic finish (jointer,planer, and TS), to basic dimensions, and not at final dimensions. I then let it sit for a few days 4-5 is great if possible.

then I cut to final dimensions. I sticker between cuttings and keep it on my bench through the process.

Another key Item I’ve found just from experience, if you are diligent in removing stock from both sides equally things behave on a more constant basis.

Anyway thats just my method from doing over many years. Could be totally whacked out, but it works for me.

Once I got out of my young years and developed some patience, things got a lot better! Made some pretty expensive kindling in my younger days.


-- Sooner or later Liberals run out of other people's money.

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667 posts in 2233 days

#4 posted 03-20-2015 01:04 AM

open the pores all the way around

-- I meant to do that!

View BroncoBrian's profile


896 posts in 2970 days

#5 posted 03-20-2015 01:35 AM

is this a bigger problem where you have more humidity and temp change? i am in Colorado and it is dry and the temp can change quickly, but overall it is stable.

-- A severed foot is the ultimate stocking stuffer.

View botanist's profile


167 posts in 4550 days

#6 posted 03-20-2015 01:42 AM

As long as I can finish before June, my main concern is humidity as we can get lots of rain in the spring.

View Dave G's profile

Dave G

337 posts in 3059 days

#7 posted 03-20-2015 09:43 AM

I live high humidity on the ocean with large temperature swings indoor versus out. I found if I follow the precautions others mentioned above the high humidity doesn’t ruin my project.

-- Dave, New England - “We are made to persist. that's how we find out who we are.” ― Tobias Wolff

View Robert's profile (online now)


4450 posts in 2492 days

#8 posted 03-20-2015 10:01 AM

You are correct its the humidity not the heat.

All the posters are correct.

The only think I would add is if the humidity is going up suddenly, as when a storm is coming or just when its a particularly humid few days, you should but the wood in plastic bags or wrap in plastic. I do this routinely because where I live this time of year most mornings start out 100% humidity.

I’ve been severely disappointed those times I’ve left wood out that’s been doing fine only to find it warped overnight.

In my experience I try to remember:

1. Go in stages
2. Equal amounts off each side.
3. Sticker and wait at least 2 days between millings if the wood is cured

When I get in trouble is when I rush the process. Depending on the wood you’re using it can take 2-3 weeks to acclimate after each milling.

There’s other common sense things too, to like:

-don’t sticker up the wood right under a fan
-or where the sun will hit it
-or next to a heat source

-- Everything is a prototype thats why its one of a kind!!

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