David Hance wrote:
Cupping is swelling on the edges of the flooring giving you a washboard appearance.
David, that is incorrect. A cupped appearance can be from several things, but the edges swelling is not one of them.
A difference in moisture content from the bottom of the board being higher in MC, to the top of the boards low MC. The bottom of the boards swells and increases in width. The top being less MC does not swell holding that width. This makes the edges curl upwards in a cupped appearance.
Another is from a well fastened floor, that gains MC from a higher then installed humidity on the verge of buckling, the pressure will crush the wood fibers at the edges pushing them upward, in a cupped appearance. It will be just the edges and the middle practically flat.