I was wondering if anyone out there has used strapping on units before kiln drying to help prevent warping of top layers on top units. If so what type of strapping was used and what were the results.
From contributor Ge
I have seen nylon (or similar) load binders that are used for securing loads on an 18-wheeler used. They work well as they can be easily tightened every day or two as the wood shrinks. Certainly, any weight of pressure on the top of a load is helpful; a roof will provide substantial help probably more because it keeps the rain off the lumber than because of its weight. I recall that weights of 10" of concrete were helpful, with decreasing benefit with less weight. I would think that the load binders would be in the "low weight" category. In any case, they weights help the top five layers mainly.
I have also seen strapping used for holding on the roofs and expect that such straps do not help warp. The straps loosen within days due to shrinkage.
From contributor Ge
I saw a study done with weights on southern pine 2x lumber and the weights were removed right after drying. ..the weights were attached to the kiln structure. During the next few days in storage as the MC adjusted to the outside and moisture gradients lessened, warp occurred, making the idea not worth it i this case.
