Installation Guide

9
GENERAL INFORMATION
MOLD TECHNICAL BULLETIN
Mold is a lower form of plant life that can settle and
grow on any surface, including Trex
®
decking. Mildew is
a form of mold that grows on damp surfaces.
Mold spores, transported by air, insects, animals, and
water, are similar to seeds, but you can’t see them
until colonies form. Because mold adapts easily to its
environments and has a large number of species, it
is hard to control and impossible to eliminate totally.
But it will not affect the structural performance of Trex
decking.
To form visible colonies, mold needs food, moisture,
and temperatures between 40° - 90°F (4°C - 32°C).
Trex decking is not itself a food source but spilled dirt
and debris from flowerpots and gutters can nourish
mold. If the gaps between deck boards are too small or
clogged, the decking can also supply moisture.
Refer to gapping instructions on page 34.
How to Remove Mold from Trex Standard
Composite and PVC Decking
All exterior building materials require cleaning. Trex
is no exception. Periodic cleaning of Trex decking will
remove dirt and pollen that can feed mold. If mold
colonies appear, clean the deck with a commercial deck
wash containing a detergent and sodium hypochlorite
(bleach). The chemical will remove the mold but also
lighten the wood. In some cases, it will take several
treatments to remove the mold colonies. Even if the
spots are no longer visible, mold spores that could
re-grow may still be on the surface.
The following brands of deck cleaners are effective in
removing mold:
» Olympic
®
Premium Deck Cleaner*
» Expert Chemical
™
** Composite Deck Cleaner and
Enhancer (expertchemicalinc.com)
Always apply these products to a dry deck. Applying
them to a wet deck will significantly reduce the
bleach’s effectiveness. NEVER mix any other cleaners
(ammonia, phosphoric acid, etc.) with bleach.
» For a non-chlorine based alternative, you can use
UltraMean
®
,*** but you must scrub the deck with a
soft brush immediately after you apply the cleaner.
Mold spreads easily and may return in some
environments despite proper cleaning and preventative
measures. Mold does not damage Trex and will cause
no structural harm.
How to Remove Mold from Trex Transcend®,
Trex Enhance®, and Trex® Select™ Decking
If you allow debris such as pollen and dirt to remain on
the deck surface, mold can feed on the biofilm. Use a
hose and warm soapy water with a soft bristle brush to
remove the food source and mold.
* Olympic
®
is a registered trademark of PPG Architectural Finishes, Inc.
** Expert Chemical
™
is a trademark of Expert Chemical, Inc.
*** UltraMean
®
is a registered trademark of Rhino Hide.