Weighing Down Stacked Lumber

Weighing down the lumber stack with concrete can help the wood dry flatter. June 16, 2014

Question (WOODWEB Member) :
My company was looking to build some cement weights for the tops of our lumber in our air dried yard to keep the top packs from warping. Does anyone have any knowledge in this and maybe some guidance on what to do and use? How heavy do they need to be, etc.?

Forum Responses
(Sawing and Drying Forum)
From Gene Wengert, forum technical advisor:
Every bit of weight helps. Also, the weights act as a roof to shed water and this is a huge benefit, maybe more than the weight effect. Weights benefit the top three-five layers. Concrete weights are often used up to about 10" thick; rebar is necessary. The greatest benefit is with 150 pounds per square feet. More than this is not helpful. Note that with several packs of lumber in one pile the bottom packs already have a lot of weight. Do you notice that the lumber in the bottom packs is flatter? Oftentimes, the bottom lumber is not flatter because stacking is not perfect. The key to effective top weights is perfect stacking and 4x4’s under every sticker column.

---

From the original questioner:
If we used that much weight we would not be able to lift our packs with this on top. I was wondering if 60 pounds per square foot would be good?

---

From Gene Wengert, forum technical advisor:
Try one at about 30 and one at 60. I think you will go with 30 after your test.

---

From Contributor O:
Gene - so 30lbs per square foot? If my stacked wood surface area is 80 square feet (5'w x 16'L for example), then you're saying the weight to be placed on top would be 2,400lbs?

---

From Gene Wengert, forum technical advisor:
Yes. 10" of concrete has been used.

---

From Contributor O:
Got it – thanks.

---

From contributor A:
I have not done this but maybe this would work. You can fill containers with water, maybe even build your own. A cubic foot of water weighs 62 lbs. If you could build a lined box the width of the stack and make it waterproof in 2' increments and the stack is 40" wide by 10' long, that would be five boxes 24"x40"x6" deep. At 6" deep the water would weigh about 30 lbs per square foot and you could have a simple drain cock on each box draining into a 55 gallon drum so water could be re-used.

---

From contributor Y:
To contributor A: Your idea just might work for people like me who have limited means of lifting weights. Thanks for bringing it up. I'm thinking of troughs that could be lifted in place - maybe a bit of antifreeze for winter weather.