how common is wood movement really?

Mike Gager

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ok as a precursor to my question please be aware im very new to all this!

anyways i see lots of talk about wood movement on certain furniture pieces because of weather and humidity changes yet personally ive never encountered or noticed this before on furniture. we have quite a bit of wooden things in our house and ive never noticed anything change size or warp or anything like that. the only thing i can recall noticing is our front door sticks pretty bad during the summer but opens fine in the winter. its an original to the house (1930s) solid wood door

anyways i guess im just curious how often this really happens or is it more of something to be aware of possibly happening when designing/building a piece of furniture or whatever?
 
Couple things:

Wood movement is 100% - if it's wood, it moves. To what degree depends on a few things - width, thickness, humidity differential (what it has vs. what it's surrounded by), and sometimes temperature. Temperature's usually not a problem, but humidity certainly can be. The width of your stock certainly plays a very large role in how much movement can happen. Generally, I expect as much as 1/16" for every 12" of width. It also depends on species - some will swell up more than others. The Dept. of Forrestry (i think) has a bunch of information on this. Google "Wood as a structural material". That will give you charts and tables on just about every aspect of wood.

The other thing is - there may be a very good reason you haven't noticed anything with the wooden things in your house is that they were built with movement in mind. Properly done, nobody should ever know. The exception to this is in some styles where a breadboard end or some other cross-grain situation exists. Another possible explanation is that all the parts that COULD suffer from movement are made of plywood or some other veneer or movement-neutral material. Plywood and veneers over MDF and such are very stable and don't generally move much - which could also explain why you haven't witnessed any appreciable movement.
 
Jeff's pretty well got that one nailed. You don't have problems because either your furniture is solid wood and well designed or is composites and doesn't care. I think we've all come across at least one piece of furniture where things have gone wrong; warp, split, loose-joint, etc.

I am "restoring" Grandma's dresser for LOML. I am not going to repair the warped top as the failure was due to poor design. The whole piece, although old, is poorly designed and was not a good piece even when new. Just because they didn't have K-mart back then doesn't mean everything was well built.

I live in SoCal and except for the extremes of beach, low desert and high mountains, the differences in humidity around here are pretty mild. I still design for movement as I would like to think that after I'm gone, a great grandchild might still have one of my pieces in her home in Vermont. ;-)
 
You know those sounds that often get desmissed as the house settling? That's your house going through it's annual expansion/contraction. The really loud ones are where 2 different materials are fighting against each other and finally let go with a loud pop.
 
This is a 24x24 table top I built a few years ago from red oak. The breadboard ends were perfectly flush when I finished it. Every winter it looks like this. In the spring when it is wet but we aren't running the heat much, it pretty much goes back to flush, but never completely. In the summer it varies depending on how much we run the AC. For reference, the dowel that pins the breadboard end on is 1/4". The breadboard is sticking out at the back by the same amount right now. The hidden part of the underside of this top is not finished, which probably contributes to the movement.
 

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Ancient Egyptians cut large granite blocks by drilling rows of holes, pounding in wooden stakes, and then pouring on water to swell the wood. Furniture designed with movement in mind is fine. If improperly designed, it can behave more like the rock.
 
This past spring i put 600 s.f. of 3/4" thick tongue and groove white oak flooring in my house. It was custom milled (narrow plank) and dried to 8-10% moisture content and acclimated properly before i installed it. I put it in nice and tight - no gaps anywhere. It was sanded and finished in place. All was perfect until late December, when the St. Louis summer humidity was long gone. As the floor adjusted to the lack of humidity, it shrank and popped throughout the day for several weeks. Now it's done, and i've got gaps about a hair width's thickness scattered across the floor about every 4th or 5th course. I loved it when it was still "perfect", and one of the reasons i went with the narrow plank flooring is because of it's greater stability over wide expanses - but i knew this would happen. This summer, it will swell tight again.
It looks just fine - no one really notices the tiny gaps. Hopefully, it will carry the house through another hundred years.
All materials move - even concrete. I have to constantly be aware of this as part of my job as an architect. I'd run into trouble from all corners if i ignored that. If you design things to accomodate the movement, you'll be much better off.
Paul Hubbman
 
ok as a precursor to my question please be aware im very new to all this!

Wood movement? What movement? Would you like to see the garden table I built and my wife wouldn't allow me to put spaces between the slats to allow for wood movement? It rained during the night I put the table out and most my corner joints broke. The table is fine now, and I was vindicated.

DKT
 
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I built my daughters Train shaped cradle and was very proud of it...especially the drawers. They fit so well that when you slid the drawer in, you could feel the displaced air coming back out at you. That was pretty good woodworking I thought.

Now every time it rains, the drawers "stick" because the wood "moved" just enough to bind.:doh::huh::eek:

Locomotive_Cradle-454x336.jpg
 
Well, it seems you got a host of ideas and concerns about wood movement (I personally hate that term, It is expansion and contraction due to climate conditions and temperture as well as the moisture content of the ambiant atmosphere surrounding the inquestioned piece.

OK movement is an easy way to say it...:eek: But it is strickly expansion and contraction. Wood will expand across the grain (in all directions) depending on the moisture content and the weather conditions. (It will also expand lengthwise but in a slight amount in comparison to the width. ) Wood will contract according to moisture content as well as weather conditions. Allow for the expansion and consider the contraction and be aware of the events that will unfold (as was spake to you on the first response, It will happen 100% of the time but the limitations of where it is and how much is determined because of a host of reasons.

Some sooner WWers will shout about how you can't do this or that because it will "Move" and fail. But, today's finishes and well seasoned wood plus the conditions of our modern homes often diminishes these "Movements"

I had an old Bed with Burl Veneer on the headboard and for over a century it was intact but one night (when I lived in an old house with forced air heat ) during the coldest of winter "POW" I thought a gun had gone off in the middle of the night. :eek: Next day I found a sever crack all the way across the Headboard, down the middle of the veneered panel. :huh: Bummer! :( For a Century it had survived weather changes and Winter /summer changes but never had it been subject to Hot dry air on a cold dry winter's night, The backing board (walnut) shrank to the point where the Burl veneer colud no longer withstand, and a failure occured. But for 100 or more years that bed was fine and in good shape, so is it a problem, not if you allow for changes, but the craftsman who built the bed had not a clue it would be subject to such dry conditions. The bed was born in the South with Hot Dry summers abound but they are not as dry as a heated air space on a cold dry winter's night.
 
Previous posts say it well. There's an excellent book out there by Dr. Bruce Hoadley entitled "Understanding Wood: a Craftsman's Guide to Wood Technology". Available from Amazon, free shipping. If you find it elsewhere, get the second edition...some additional material, plus color photos. If you work with wood, everything in this book is worth knowing, and there's an excellent discussion of moisture in wood.
 
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