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Composite Deck Mold

:confused:Is there a sealer that can be used on composite deck lumber (Trex) to keep mold from returning once the deck is cleaned? We have been able to clean the mold off with certain cleaners, but it returns within a couple of weeks completely covering the deck with black mold.

Re: Composite Deck Mold

Try using a deck cleaner made by Behr, which seems to kill the roots of the mold/mildew. Keep in mind that exessive cleaning will shorten the life of your composite planks.

Then use a product called Seal Once, with some luck it should stop new mold.

I had a friend in Fl who complained about repeating mold on his wood fence and this product helped him.

Re: Composite Deck Mold


If you have the orignal version of Trex, I would consider painting it with a 100% acrylic porch and deck paint, after a thorough cleansing to kill the mildew and algae. I know, this is not why you bought "maintenance free" synthetic decking, but it will provide a better seal to the porous Trex surface. Good deck paints will also contain a mildecide. A 100% acrylic paint will also hold its color better than the original un-coated Trex.

If you want to maintain the same color as the original Trex, Behr has a color chart with all the Trex colors. Obviously, you can also change the color, but I would be leery of a really dark color.Plastics generally do not hold their strength when they get hot.

Re: Composite Deck Mold

you can buy a 1 gal bleach pump up sprayer from Home-Depot. Make a mix of bleach-water-Borax(detergent) and a tiny bit of ajax. Spray it on the deck and use a soft brush to spread it around, let it sit for a few min until you can see a difference then hose it off. What happened was the mold actually was removed by the roots. At this point, they make stains for trex and other composite decks now, maybe you should look into them? hope this helps

Re: Composite Deck Mold

I have used a product called shock wave. very good stuff, but you will have to solve what is actually causing it

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