What construction feature of plywood prevents it from warping?

Plywood is specially designed to resist warping due to its unique construction method, which involves layering multiple thin sheets of wood called veneers. The critical feature that prevents warping is the orientation of each ply, which is positioned at right angles, or ninety degrees, to the adjacent layers. This cross-laminated structure distributes stress more evenly across the wood, counteracting the natural tendency of wood to expand or contract with changes in humidity and temperature.

By alternating the grain direction with each layer, plywood reduces the likelihood of bowing or cupping that can affect solid wood panels. The cross-grain arrangement helps to stabilize the material, making it much less prone to distortion. Therefore, this construction method is fundamental to plywood's performance, ensuring it remains flat and retains its shape even when subjected to environmental changes.