by noseoil » Tue Jun 09, 2015 7:56 am
A "normal" solid wood can & will swell up to about 1/8" per foot across the grain when humidity changes. Plywood isn't as bad as a solid panel, but it can still move around a bit. I'm building in 5% relative humidity where I live in the summer, but this jumps up a lot during the monsoon season, from July to September most years. Best to allow for some movement in the design & minimize it as much as possible by sealing up all the edges & end grain as you go.
P.S. Thanks for the clarification in your thread title.....