Cottonwood for Barn Siding

Advice on using Cottonwood for board and batten siding. June 18, 2010

I have access to large cottonwood logs and wish to cut them into 1 X 12 boards and apply them to the sidewall of my barn. The barn has a 24" overhang, and the spaces between the 12" boards will be covered with 1 X 3 battens. All of this siding will be applied vertical. The boards will be nailed to 2 X 6 girts 36" apart. Should I dry them first or apply green? I have never used cottonwood for siding. I live in the Pacific Northwest.

Forum Responses
(Sawing and Drying Forum)
From contributor C:
I would nail them up green...You will notice quite a bit of shrinkage and some splitting over time, especially on the south side, but with board and batten it doesn't matter as much. I would use 3" galvanized or stainless deck screws to hold them flat. Pallet mills around here love cottonwood.

From contributor J:
I've built a few barns with it. It helps to have a foot of overhang or so. I used ring-shank nails and nailed the boards in the center for a couple of weeks, then when it dried a little I nailed the boards down. Helps with splitting. Got a semi-colored stain and sprayed the wood. It has held up for many years - will be around longer than I am.

From Professor Gene Wengert, forum technical advisor:
Cottonwood is probably not the best species to use, but it will work well if you can keep it dry and allow for some movement. Ring shank nails are indeed important. Installation of green wood is okay, but plan on substantial shrinkage and even some warping. Because the pieces will be trying to shrink about 3/4" in width, if you nail down the edges, there will be tremendous stress and the pieces will likely crack in the middle. Therefore, nail in the middle and allow the edges to move unrestricted. Make sure that the batten nails do not restrict movement of the pieces underneath. Decay resistance is nil, so using gutters on the roof might be a good idea.

From contributor S:
I sawed for a guy with a 100 year old barn with cottonwood siding that's still in good shape except for where it's close to the ground. Try keeping it 8" or so off the ground.

From the original questioner:
Thanks, all. Great info!