Cleaning Trex Decking

How to clean composite trex decking is a big issue for many people. First, two important points regardless of what sort of cleaner you choose:

• Composite decking is not well-suited to damp climates because damp encourages mold growth in the timber part of the composite.
• Cleaning regularly is important. If dirt, leaves, pollen etc. are allowed to accumulate on the decking then this will provide better conditions for mildew and mold to thrive and produce unsightly stains.

Which Composite Decking Cleaner?

Many people use bleach to clean their composite decking but are not happy with the results. Bleach will remove mold spots from the surface of the decking but it soon returns. Here is a forum comment on the use of bleach:

"Chlorine Bleach or Sodium Hypochlorite (active ingredient in Chlorine Bleach) based deck cleaners that the uneducated recommend may appear to quickly remove mildew (white in color) and mold (black and other colors) fungus from Trex and other Composite Decking. Nothing could be farther from the truth.
The Environmental Protection Agency (EPA) and the Occupational Safety & Health Administration (OSHA) DO NOT RECOMMEND Chlorine Bleach for Mold (Mildew is a species of Mold) remediation on porous surfaces such as Trex and other composite decking.

The reason for this is that Chlorine Bleach does not remove or kill the roots (mycelium) of the fungus, but actually waters them. A few weeks after you have cleaned a deck with chlorine bleach or sodium hypochlorite based products you will notice the mildew or other mold fungus growing back in greater numbers, especially after additional moisture comes into contact with the deck. It will make the problem worse and harder to remove the next time the composite surface becomes unsightly.

In addition, Chlorine Bleach products reek havoc on the rest of the deck structure shortening the life of the entire structure. It is highly corrosive to any metal including structural connectors or fasteners (screws) holding the deck together. It shortens the life of the pressure treated lumber supporting the deck. This could lead to liability issues for the owner of the property and any company who recommends its use."

 Many composite deck owners have found better cleaning results from using brand name removed at request of trademark owner. Here are a couple of comments on it from the same forum:

"I have used a new composite deck cleaner called brand name removed at request of trademark owner (website removed at request of trademark owner) now being recommended by Trex for all of my cleaning issues. It works far better than anything else. It kept the mold away far longer than chlorine bleach or oxlaic acid based products and cleaned the deck far better than anything else. It is also environmentally friendly and less money. I highly recommend it!"

"When it came to removing the black mold and mildew spots brand name removed at request of trademark owner worked far better and for less money than the PSC Composite Deck Restorer with out the harsh chemical smell or potential dangers of chlorine bleach. brand name removed at request of trademark owner did not corrode my fasteners or kill my plants like the chlorine bleach based products.

I noticed that after using the chlorine bleach based products that contain sodium hypochlorite (active ingredient) to remove the mold, the mold never was completely removed. I noticed black spots only when the deck was still wet. Any way, the mold grew right back. In fact, all I was doing was removing the dead surface layer of the mold and was watering the mold roots. See the links on the brand name removed at request of trademark owner web site to OSHA, the EPA and Spore-Tech before using chlorine bleach on a POROUS surface like Trex composite decking."

There are lots of great videos on YouTube that show you how to clean your deck correctly:

Clean composite decking videos