Green Shoots Blog
If all other cleaning techniques fail to clean or remove stains from your composite deck, you may try sanding or having a professional powerwash the deck.
Dirt and Debris:
Spray the affected area with a water hose to remove dirt from surface. Use warm soapy water made with mild dishwashing detergent and a soft sponge/rag to remove any dirt buildup. Thoroughly rinse off with garden hose when complete.
Oil and Grease:
All oil & grease spills should be cleaned up as quickly as possible. Use warm soapy water made with mild dishwashing detergent and a soft sponge/rag to remove any oil or grease. Thoroughly rinse off with garden hose when complete. The deck surface must be cleaned within 1 week to maintain the stain portion of the warranty.
Mold and Mildew:
Mold & mildew are commonly found on outdoor building materials. To prevent pollen and debris buildup, periodic cleaning is best. If mold/mildew is present, use warm soapy water made with mild dishwashing detergent and a soft sponge/rag to remove. Thoroughly rinse off with a garden hose when complete.
Ice and Snow:
Apply calcium chloride or rock salt if needed. Be sure to thoroughly rinse off deck surface later on to avoid residue build up. A plastic shovel may be used; Never use a metal shovel or sharp edged tools to remove snow and ice.
For Stubborn Stains:
You may come across a stain that is particularly stubborn. First, try other cleaning methods and then wait a couple months because sun exposure usually helps stains disappear. If after this time the stain is still there, you may try sanding or pressure washing.
Remember that these should be last resort options. If done too harshly, sanding can affect your deck’s original texture and is generally not a great idea. However, for very stubborn stains you may try lightly sanding the area with paper that has a very fine grit.
Same thing with pressure washing. In general, we do not recommend it because if done incorrectly it can cause damage to composite decks. However, skilled professionals using washers with low pressures (under 15-hundred PSI) and wide fan tip nozzles spraying at least 12 inches above the deck surface may do the trick.
Again, these are last resort cleaning options and should only be attempted if regular clean-up solutions have not worked.