Cause Plywood cracks from its expansion and contraction with changing moisture content. Plywood is prone to cracking because of its original method of manufacture involving peeling thin sheets of wood from logs. Stresses are induced which later show up as cracking. Many small fissures are produced in films of paints and stains that have been applied to insufficiently dry plywood. The edges of these cracks protrude upward and can be felt as sharp burrs. Subsequently, this coating may become detached from the edges of the cracks and lead to flaking.
Solution New wood: To prevent cracking of newly installed plywood, sand and prime with Sherwin-Williams Latex Exterior Wood Primer. Repaint: If cracking is severe, replace the wood, for this is an unpaintable surface. If the cracking is not extensive, sand surface smooth. The plywood must be thoroughly dry. Apply alkyd or latex primer.
