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.
This could be a bad suggestion but do you have a dehumidifier? I would loosely stack it so air can get through, so crosshatch type stacking. Place some cinder blocks or other heavy weight on top to keep it from warping, and then put a dehumidifier in your garage.
Honestly having a dehumidifier is worth it regardless of this project so you should probably buy one anyway. They can turn a not so fresh smelling room in to a much better smelling one. They can help inhibit mold and fungal growth. They can even help reduce cooling costs depending on how they are connected and vented.
~dad