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Forum topic by Woodbum posted 561 days ago 684 views 0 times favorited 12 replies Add to Favorites Watch
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Woodbum

356 posts in 1568 days


561 days ago

I have wondered for quite a while about wood movement in our modern heated and cooled homes; where the humidity level remains fairly constant. I lived for a long time in SW Missouri, and have lived in Central Oklahoma for the past 21 years. We normally have gone from heating to AC and back, rarely opening the windows because of all of the wind and dust there and here in OKC.

Is wood movement minimized over the long term in temperature/humidity controlled environments?

I think that it must be. I built a G & G entertainment center ( my apologies to Darryl Peart) with quarter sawn white oak 3 years ago, and the top is 20×72, edge joined 5/4 +/- with breadboard ends. I have noticed 0 movement at all in this top since completion. Over the years, I have noticed very little if any movement in other pieces in my house, mostly constructed with flat sawn red oak. Help me out here. What do you guys out there think? I would like to think that it is due to my superior design and construction techniques, but I really think it is because of a fairly constant humidity level. If I am mistaken, please tell me how and why. Let the discussion begin!

-- Improvidus, Apto quod Victum-- Improvise, Adapt, Overcome


12 replies so far

View CharlieM1958's profile

CharlieM1958

15547 posts in 2721 days


#1 posted 561 days ago

I think you are absolutely correct. changes in moisture content is what cause wood movement. If a piece starts out sufficiently dry and is kept at a relatively constant humidity, wood movement should be negligible.

-- Charlie M. "Woodworking - patience = firewood"

View ErikF's profile

ErikF

242 posts in 747 days


#2 posted 561 days ago

I believe you hit the nail on the head. When I first got into woodworking a few years ago I didn’t have any knowledge of wood movement and built a coffee table that allowed no room for movement. It has been at my parents house for years and I figured it would have been splitting or twisting by now. It has stayed at a similar humidity level throughout its life and I would like to say this is the reason it hasn’t had any issues.

-- Power to the people.

View gfadvm's profile

gfadvm

9567 posts in 1193 days


#3 posted 561 days ago

We rarely have the windows open but burn a big wood stove 24/7 (starting today!) and it really dries the air. I notice wood movement in my wood floors more so than in furniture.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View Lifesaver2000's profile

Lifesaver2000

492 posts in 1615 days


#4 posted 561 days ago

Unless you have somehow measured the humidity in your home, do not assume that it stays constant even with modern heating and cooling systems. My heat pump system actually uses humidity as well as temperature in determining when and how long it should run, and the humidity in my house can still get as high as 60% in the summer time here in Arkansas. In the winter, I see readings inside as low as 25%. We sometimes even run a humidifier in the winter to add moisture to the air.

Of course, without the heat pump I might see summertime humidity near 90% with 100+ temperatures, so the readings I get are still an improvement. And I don’t know how much that 35 point swing in humidity level from summer to winter would actually affect the wood.

View MonteCristo's profile

MonteCristo

2088 posts in 691 days


#5 posted 561 days ago

As others are saying, wood movement is generally a lot less than in houses in the old days, but I think it’s false economy to ignore it when building in solid wood. Sealing up your house so nothing from the big bad world gets in also seems short-sighted to me, but then I live in the coutryside where a guy can actually breathe the air outside.

-- Dwight - "Free legal advice available - contact Dewey, Cheetam & Howe""

View Gregn's profile

Gregn

1642 posts in 1486 days


#6 posted 560 days ago

I live in the same environment as you, and agree as long as the relative humidity level in the air stays constant there’s little movement. You will notice that doors, windows and floor boards move first due to having exterior humidity changes exposed to them, whereas the interior humidity level stays relatively constant.

-- I don't make mistakes, I have great learning lessons, Greg

View ChuckV's profile

ChuckV

2269 posts in 2030 days


#7 posted 560 days ago

I agree, seeing things from the other side.

Our house was built in 1800 on the foundation of the original 1738 house. We have wide swings in both temperature and humidity inside the house – we enjoy knowing what season it is in New England! Our only AC is in the bedroom. We open the windows as much as possible. When it is cold, we use a wood stove non-stop. I see lots of wood movement in the pieces that I have made. It is especially apparent in the fit of the drawers that are in the room with the wood stove. So far, everything has moved as designed with no damage. But, I have had to trim a few drawers during the hot and humid times.

I try to take into account the conditions in my shop when I fit the drawers, but I am always a bit conservative. I know that I can always plane off another few thou if I have to, since I am the customer.

-- “A clear conscience is the sure sign of a bad memory.” ― Mark Twain

View Wildwood's profile

Wildwood

861 posts in 637 days


#8 posted 560 days ago

Without constant monitoring of wood and relative humidity not sure would see wood movement. If wood reached +/- 1 or 2%, EMC prior to construction not sure could measure appreciable amount of wood movement, kept in same environment. Properly, applied film finish will slow down wood gaining & loosing moisture but not stop it. Oil finishes might do nothing to stop water vapor exchange.

What would happen to that piece of furniture if moved into unheated and non-air conditioned space permanently? Again, without constant monitoring might not see much difference for quite some time.

One reason quarter sawn wood used in flooring is because minimal wood movement. What would happen to that quarter sawn wood floor if pipe broke and flooded the flooring for couple of hours?

Moisture Relations and Physical Properties of Wood

http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr190/chapter_04.pdf

-- Bill

View Rick M.'s profile

Rick M.

3384 posts in 883 days


#9 posted 560 days ago

Moisture causes wood movement. Minimize the change in moisture and you minimize the movement, no secret there.

-- |Statistics show that 100% of people bitten by a snake were close to it.|

View a1Jim's profile

a1Jim

109409 posts in 2080 days


#10 posted 560 days ago

As Bill said building with quarter sawn wood helps minimize wood movement.

-- http://artisticwoodstudio.com Custom furniture

View Wildwood's profile

Wildwood

861 posts in 637 days


#11 posted 559 days ago

I have a quarter sawn/turned bowl that went oval on me. Guess wood didn’t reach EMC.

-- Bill

View Nomad62's profile

Nomad62

668 posts in 1461 days


#12 posted 559 days ago

If using dry wood and keeping it in an evenly controlled environment is part of you superior skill set, then of course that is to credit! All of this is excellent fodder and proof that a person should acclimate their wood to the environment that it will be kept in…as well as possible anyway. And, I’ve met Darryl Peart, heck of a nice guy!

-- Power tools put us ahead of the monkeys

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