Composite decks need basic cleaning twice a year – typically spring and fall. Sweep off debris, wash with warm soapy water, and rinse thoroughly. That’s essentially it for regular maintenance.Occasional deeper cleaning might be needed if you have tree sap, grease stains, or mildew in shaded areas. Most stains come off with gentle scrubbing and appropriate cleaners. Avoid pressure washing above 3100 PSI to prevent surface damage.Unlike wood decks, you never need to stain, seal, or sand composite materials. They won’t rot, warp, or attract insects. The biggest maintenance task is keeping drainage areas clear so water doesn’t pool on the surface.