Cupping and Crowning in Boards
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- Опубліковано 22 кві 2023
- Here's a short video where we look at the cup/crown tendencies in boards and talk about how to predict it and how to work with it. Examples are given for proper orientation with flooring/decking and board & batten siding.
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Love your channel! The 800 pound gorilla that was not discussed is slab sawing vs quarter sawn. if you want/need stable wood that dries much more evenly with far less cupping and twisting choose quarter sawn. Quarter sawn wood is so much more stable--period full stop. Me personally, when I take the time to cut and transport a log to my mill and then move it to my solar kiln for a month I want a great product on the other end. So in my opinion there is quarter sawn and fire wood. Of course some bigger slabs and cookies are fun to play with but quarter sawn white oak it very stable for outdoor conditions including direct sunlight.
Excellent information!
Great Video!
I try to stack and sticker such that the heartwood is up (smiling pattern looking at the ends, i.e. bark side down) since the top sides dry faster. This seems to minimize the cupping if that makes sense.
I did believe that to be a thing, but I haven't found that makes any difference with fir stickered every couple feet or so. In the interest of speed and stacking odd sized live edge planks, sometimes you don't have that luxury anyways.
Very interesting appreciate you sharing your knowledge. Question for you, when siding with B&B where do the nails go for in the baton? Also do the baton nails go just into the boards or all the way through into the framing? Thanks
Best is to nail battens dead center and ideally the nail goes right in the gap between boards to avoid nailing the boards on their edges (a grazing shot is fine). I use 2" ring shanked siding nails for the main boards and 2.5" nails or 3" #8 deck screws for the battens. There is a diagram at 7:47 in the video that shows the fastener arrangement.
Thanks much, I reviewed the diagram and picked up on exactly what I should of seen the first time through. I also really liked your tutorial on tractor loader ballast, 👍👍
When I look at boards that are out of the weather then you’re 100% right. When I look at boards that are on my deck for years, in rain and snow, then 75% of my boards cupped on the bark side, opposite of what you’re saying.
The bark side cups, which is exactly what I said in the video. If 75% if your boards cupped on the bark side then it matches what I explained in the video.
There will be exceptions that buck the trend and I can make a board go in either direction with selective application of moisture. But the normal behavior is very consistent and has been observed for hundreds and hundreds of years.
What if you are using the Marksman Camo pro for cedar decking. Since it screws at an angle on the side(hidden) will it matter if it's crown/cup facing up? Still framing my deck, was wondering before installing the deck boards.
In general you want deck boards bark side down for longevity, so that if the board misbehaves you get a crown that sheds water (instead of a cup that would trap water and accelerate rot). Faster type doesn't factor into the logic.
My deck did the opposite and I had to flip several boards. I had to place them bark side up. When I placed them bark side down they cupped.
@jesmoreland1104... Same with my yellow pine deck boards. I'm in SE US, long hot, humid summers. Right now, I'm finishing up redoing rotted 2x6 joists. The builder had joists at 24 on center. I had to replace many and add many for 12" - 16" on center. I taped all joists. The center of 20' X 20' deck is octogon shape, with boards going from outer end to center. Imagine a pie or pizza cut into 8 slices, with deck boards going from crust to the center of pie/pizza. With 8 eaah 4x4 posts, 6ft apart at the crust edge of pie/pizza. So many 22½ degree cuts. I'm almost done with deck boards. Between the rain storms and 100°+ weather, it's a 6:00am to ~ 12:00 pm job.
But this over 65 yr old grandma is "getting it done." Sorry for the long post, but I'm heat whipped.
IN short: The lines want to flatten out.
I hate to disagree with a man I have so much respect for, but here it comes regardless. In the blistering sun of the southern United States placing your boards like that will cause a lot of the piths to pop out of the board. Plus it causes worse cupping. I’m talking overall averages. There are some boards that do the exact opposite…the outliers. If we install boards like that on the side of a pole barn let’s say, the results will be horrible. The center dries out quicker and it will cup quicker and you’ll see the two edges of the board pushing against the metal siding.
I’m beginning to believe this much be a regional thing.
Been building pole barns with board & batten wood siding in southeast Virginia for over 30 years and never seen any of that. Given our hot summer temperatures, I can't think it gets that much worse farther south. Could be related to the species of wood though. I use white pine, SYP, or poplar for siding and have not had issues with any of those. Hardwoods are much more finicky and am not a fan of them for siding.
I've had luck misting with water to coax boards back into shape until I get it stained or whatever... if they're drying too quickly. Say, for example, on a fence... hit the cupped side