Need a recommendation on whether to use treated plywood for bar top layers or is OSB sufficient. I am using tile as the finish layer with Hardie Backer Board underneath. Plans call for CDX and then a better finish layer but will that stand the humidity in the south?
Also, how do you get the 3/4″ plywood/OSB to remain level and straight on the exposed corners(not supported)? Seems like there may be some sag or warp over time?