Symptoms
- Overall color lighter than when installed
- Dark spots from leaves, berries, or spilled food/grease
- White or chalky mineral marks from hard water or sprinklers
Likely causes
- CommonUV fading over timeMost composite decking fades somewhat in its first year or two before color stabilizes, especially in sunnier climates.
- CommonOrganic staining from leaves, pollen, or foodTannins and oils from organic debris can leave marks if not cleaned promptly.
- PossibleMineral deposits from hard water or sprinklersRepeated wetting with hard water can leave white mineral residue on the surface.
What to do
- Sweep the deck regularly to prevent leaves and debris from sitting long enough to stain.
- Clean with warm water and a mild soap using a soft-bristle brush, following the manufacturer's cleaning guidance for your specific composite brand.
- For grease or organic stains, use a composite-deck-safe cleaner rather than a generic degreaser, which can discolor some products.
- For mineral deposits, a diluted vinegar-water solution or a hard-water-specific cleaner often works well; rinse thoroughly after.
- Avoid pressure washing at close range or high pressure, which can damage the surface texture of some composite products.
- Adjust sprinklers so they don't spray directly and repeatedly onto the same deck area.
- Expect some initial fading to be normal and check your product's warranty terms if fading seems excessive or uneven.
Tools and parts
- Soft-bristle brush or broom
- Garden hose
Composite deck cleanerSearch: “composite decking cleaner”
When to call a pro
Call a deck cleaning service for a full restoration, or contact the manufacturer if fading or staining seems out of line with normal expectations.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.