Annual wood movement? Not here!

[Jamie Buxton]

For all my life I've been reading about annual wood movement -- that wood expands and contracts across the grain in response to changes in atmospheric humidity. I've built furniture which accommodates that movement -- floating panels, sliding joints, table buttons, etc. However, as I've watched the woodwork in my home, I haven't seen much evidence of movement. So I finally got formal about measuring the movement. I picked a solid-lumber panel in my home, and measured its width every month for a year. The panel is a slab door, so it has no constraints on it to prevent it from moving. It is 14" wide by 3/4" thick, made from three cherry boards that are mostly flatsawn. As it turns out, the width of that door has measured 13.97" or 13.98" each month for the entire year. That is, there is just no annual movement -- none, zip, nada.

[Mike Henderson]

Yep, California does not have a lot of weather variation. And since the door is in your home, you have even less variation.

My experience is that the east coast experiences a lot more variation and a lot more wood movement.

Mike

[Dick Mahany]

I recently relocated from the SF Bay area to the very arid Palm Springs desert. I noticed a very significant change to the floating breadboard ends on five mission/craftsman style tables that I built out of QSWO. The ends were flush in the Bay Area, but now have a misaligned step ~.090". All five tables did the same thing.

Afterthought: I built these table tops with wood that was very dry, but during the wet Dec-March south bay months in my garage/shop which was non temp or humidity controlled. They saw relatively little movement until this summer when I moved into 108 degree temps with near zero humidity.

I'm just glad that I spent all of the time to allow a full float on the BB ends , as any other joinery would likely have self destructed by now.

328459

[Max Neu]

I have seen some pretty significant wood movement over the years,not in my own house,mainly where people have very dry heat sources in the winter,and don't do anything to add moisture back into the house.

[Cody Colston]

Wood expands or contracts, mostly across the grain in response to changes in RH. Some woods move less, some more but they do move. Any argument to the contrary is not worth considering.

[Phil Stone]

What's interesting about the micro-climate here in the Central Valley of California, is that there are huge diurnal swings in humidity. In the summer, it can get up into the high 90 percents at night as the moist coastal air comes in with the Delta Breeze. In the heat of the day, it can be as low as 25 percent. However, the daily average is very consistent, and doesn't vary much throughout the year. I guess wood can't react that quickly, and so it is the daily average that matters*. And yes, I've noticed very little wood movement here, but still design for it, in case either I or the piece moves to a different part of the world.


*That daily average *does* matter...when drying wood. Just for fun, when I was drying the doug fir for my workbench, I kept track of the weight loss plotted against the daily average relative humidity, and there was a very clear correlation between the two.

Edit: I'm wrong about the yearly swing of the daily average; it's actually fairly significant: ~75% January -> ~34% July. That *should* be enough to cause a bit of wood movement. The *indoor* swing is actually much less, though, because our heating season coincides with the higher humidity, unlike the east coast.

[Lee Schierer]

I built a maple dresser for my son here in NW Pennsylvania using kiln dried maple with finish on all surfaces inside and out.. I shipped it to his home in Tucson, AZ. The bread board end on the top was flush when I finished making it. After a year in his house in Tucson, the main field of the top was 3/16" narrower than the end board. It stayed that way as long as he lived in Tucson. After they moved east to a location near Syracuse, NY, the dresser top returned to its original dimensions.

[Bruce Page]

You won't see much movement in New Mexico either. I've only had 2 failures, one was a 30"x30"x 3/4" oak end table top trimmed with 2"x 3/4" walnut all the way around. It went several years before the corner lap joints failed. The other was a mantel clock I made for my sister that basically exploded several months after arriving in her Hawaiian home. It couldn't handle going from 10% humidity to 90%.

[Peter Aeschliman]

As others in this thread have noted, all of the tables I've made with breadboard ends have shrunk considerably. All of them were build in my insulated shop, but I only heat it when I'm working. When moved into homes with forced air furnaces, they shrink a lot...