There was a great topic in a recent article of Ask the Builder by Tim Carter about some common problems with Trex and other composite decking. These composite decks are typically less maintenance than a wood deck, but aren’t no maintenance.

Some common problems profiled were:

• Mold and Mildew
• Tree Sap
• Uneven Board Treatment or Composition

Tim  points out that Trex has a good cleaning guide on their website. He has had the best luck cleaning trex with oxygen bleach applied with a stiff broom.

For more:
– Ask the Builder Trex Article

-Trex Cleaning Guide