Concrete bases: An air-drying necessity?

Bases and stacking techniques for air-drying lumber. November 29, 2000

Q.
Do I need a concrete slab to serve as a base for my stacks to be air dried, or can I use 4" X 4"s? What other items should I pay attention to when laying the air dry stack? (As you can tell, I am new to the club.)

Forum Responses
The most important thing in my mind is whether you are going to get rain or not. If so, then you need to ensure proper drainage from under the stacks. If you do not provide proper drainage, the wood will soak up the moisture as it evaporates and cause the bottom layers to be wetter than the rest and will also mold if the temperature is above 72F.


I use three 8" square concrete blocks spanned by half a landscape timber as a base for my stacks. This gets them high enough off the ground to deal with excess moisture. Search the archives for stacking and for stickering. These subjects have been discussed in detail.

I use two 4" X 6" timbers the length of the stack I need and set them on 8" concrete blocks with 4x4's on top of that spaced from 16" to 24" apart depending on the material that I will be drying. This arrangement keeps material on the bottom about 18" above the ground. It works well.

Be very careful where you place your packs of lumber. As the dirt gets wet the skids supporting the lumber will sink! This is even more critical the taller the pile. The worst is when one one side sinks, and the lumber is supported unevenly. The lumber will bend and keep that amount of bow.

Try 8"x8" spaced every 24" then place a sticker on top of the 8x8 to keep the lumber from molding. This will spread the load and limit the sinking.

A better set up is concrete pads. If you're close to a Ready Mix plant they often will have left over concrete cheap or free. But, you must have the forms 100% ready before they call or stop. Usually a 1/4 yard to 10 yards. More is rare.

Three years ago we got a call saying 100 yards of concrete was to arive in 15 minutes. That's 10 trucks all at once and it was starting to rain. We ended up getting 3 trucks with 27 yards. The plant manager was able to sell the other truck loads before they got to us.

We used our wheel loader to put light poles down as forms and called a local concrete contractor to bring his power screed.

It cost $200 for a rainy day service call from the contractor, and the concrete was FREE! ($80/yd regular price)

The wind can cause problems too--get some SHADE DRI covers.


Here in Florida I use pallets under my pole barn to air dry my wood. They are very strong and even though they are only 4" or so off the ground, the wood and pallets have remained in great shape. I spray the pallets first with Lindane before placing them on the ground to prevent termite problems. After two years now, I've had no problems and the wood has turned out great.

Also, consult AIR DRYING OF LUMBER--it is on the internet. Search the archives for a site at the US Forest Products Lab.

Gene Wengert, Forum Technical Advisor

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