The main benefit of composite decks is that there is never a need to seal, stain or paint it. Most composite decking has a warranty on splitting, rotting, cracking or insect damage. Painting or sealing a composite deck may or may not affect the warranty depending upon the manufacturer.
Most composite decking is made using polyethylene plastic or polyvinyl chloride as the base material, which is mixed with wood fiber or other fillers and a blend of chemical additives to create the boards. It is not recommended to paint or stain composite decking, but it can be done after the material has been in place for at least eight weeks to allow it to weather.