STEP 4: Rinse the deck off with a garden hose. Banish mildew with borax. If your deck has visible mildew stains, add 1 cup of powdered borax to the solution at the same time you add the oxygen bleach. Treat stains with oxygen bleach paste. Sweep away dirt promptly. Apply a penetrating sealer once a year.
I have a trex deck with black marks like leopard marks on most of the boards.. I live in the Northwest so mold is a problem, oxyclean and vinegar and really hot water and alot of. . http://www.rhinohide.com/blog/easy-composite-cleaning. Like
Add 2 cups of the bleach to two gallons of water. Pour in 1/4 cup of dish detergent and mix well until it suds. Use a broom or another large brush and cover entire deck. Scrub where there is stubborn dirt and grime and then rinse off.
I am looking for suggestions on cleaning my composite deck…there is some green mold and mildew.. Behr's Deck Cleaner, a mild oxalic acid and enzyme solution, can be used to. Zinsser's "Jomax" is also good on almost any surface.