PLAYSET MAINTENANCE Cosmetic defects that do not affect the structural integrity of the product, or natural defects of wood such as warping, splitting, checking, twisting, shrinkage, swelling or any other physical properties of wood that do not present a safety hazard, are not covered by our warranty. To help minimize these natural defects we recommend applying a sealer or stain every two or three years, or more often as the climate dictates.