I bought lumber for a screened patio, and I need it to dry so I can paint it before construction. It’s been sitting in a neat stack in the garage for almost a month now, and some parts still feel damp.
I’m afraid that laying them out on the driveway during a sunny day would cause the boards to warp.
Any wood will warp as it dries. Usually you’d build with the wood while it’s wet, so it dries in the correct position.
If you’re not able to do that, determine whether you can tolerate holes in your wood. Temporarily screw them together so they’ll stay straight (though not all bunched up, as that would take longer to dry). Then let it dry outside.
Note that, even outdoors, treated lumber can take months to dry properly. When I build something with it, I usually wait until the following spring to paint it. So you might be waiting a whole.