How to Clean a Composite Deck

Composite decking is easy to keep clean – mostly you need soap and water or a quick power wash. Learn how to choose a cleaner and clean your deck.

By: The Trex Team

July 30, 2024

When it comes to composite decks, removing months of buildup caused by weather and weekend activities is a breeze, taking the stress out of preparing your space for a new season of outdoor enjoyment. Whether you have traditional composite or high-performance shell composite, there are straightforward and cost-effective cleaning methods tailored to each type. With composite decking’s low-maintenance needs, simple tools and cleaners will quickly revitalize your deck’s rich wood grain and vibrant color with ease.

How to Generally Clean and Maintain Composite Decking

The standard method for cleaning a composite deck involves using a gentle brush and water to scrub away accumulated dirt and residue. For early-generation composite decking such as Trex Accents®, Trex Origins®, and Trex Contours®, stubborn dirt may require the use of a composite deck cleaning solution before scrubbing to lift dirt from the surface effectively.

For high-performance composites such as Trex Transcend®, Trex Enhance®, and Trex Select®, which incorporate shell technology, you can simply use warm soapy water and a soft bristle scrub brush. After scrubbing, a final rinse with clean water completes the cleaning process for both composite types.

If you're struggling to clean your deck with a soft brush, a power washer can assist with the cleaning process. Just ensure that the power washer falls between 1500-3100psi and that you're using a fan nozzle at a distance of at least 8 inches from the deck surface.

The best way to clean a composite deck is to periodically clean it throughout the year to ensure a vibrant appearance year round. Typically, a bi-annual cleaning schedule is sufficient for cleaning a Trex® deck and keeping it looking new. Decks exposed to heavier soiling may require more frequent cleaning.

Man cleaning his deck witt a garden hose

What You Need to Completely Clean Your Composite Deck

Composite decking is low-maintenance so, armed with the right tools and recommended cleaning instructions, you can look forward to a straightforward cleaning process. Below is a list of essential items you'll need to effectively restore both early-generation and high-performance composite decking.

Early-Generation Composite Decking Tools & Materials

Water Source
Garden Hose
Long Handle Soft Bristle Brush
Composite Deck Cleaning Solution
3-5 Gallon Pump Sprayer

High-Performance Composite Decking Tools & Materials

Water Source
Garden Hose
Long Handle Soft Bristle Brush
Warm, Soapy Water

Optional Power Washer with Soap Dispenser

Best Cleaners for Composite Decking

Trex Foggy Wharf deck with couch and coffee table

Knowing what to use to clean composite decking is crucial for preserving its appearance and durability over time.

The cleaning approach will differ depending on whether your deck is early-generation or high-performance Trex composite decking. Early-generation composite lacks the protective shell found in the latter, requiring a specific cleaner such as Deck Brightener and Wash. High-performance composite decking can be effectively cleaned with warm, soapy water or soap added to a power washer.

It’s important to note that many deck cleaning liquids, including composite deck cleaner, contain chlorine, which acts as a bleaching agent that can affect older types of composite decking material. It's important to use the correct cleaning products and apply them carefully and promptly to preserve the deck's aesthetics and strength.

Why You Shouldn't Use DIY or Homemade Deck Cleaners

Using DIY composite deck cleaner is not recommended due to its potential to cause irreversible damage to your composite decking. Products containing substances like solvents, high-concentration chlorine, and abrasive cleaning agents can deteriorate composite surfaces, leading to compromised structural integrity and a severely diminished aesthetic finish.

Avoid using DIY composite deck cleaners and instead opt for cleaning solutions specifically formulated for composite decking. Or make your life easy and simply use warm, soapy water. The risk associated with using composite deck cleaner, homemade or DIY, is too significant to ignore, especially when this may put your warranty at risk. For optimal results (and to make sure you uphold the longevity and appearance of your deck), it’s best to use manufacturer-recommended cleaning products.

What Brush You Should Use to Scrub Composite Deck Boards

When deciding what to clean composite decking with, it’s important to choose brushes that balance gentleness with effectiveness. A soft-bristle brush is more than enough to effectively remove dirt and grime. In instances where stubborn stains persist, using a short-handled or handheld brush allows for targeted pressure during scrubbing. If you want to avoid scratching and marking the composite surface, stay away from hard bristle or metal bristle brushes.

Despite composite decking's toughness and durability, using hard brushes risks damaging the outer finish, leading to an unsightly and compromised appearance. A soft brush will clean a composite deck without any detrimental effects if you take your time and do it methodically.

Using a Power-Washer On Your Composite Deck

Cleaning composite deck boards with a power washer offers efficient results, but you need to be careful. It's crucial to ensure that the pressure always remains under 3100 psi, you’re exclusively using a fan nozzle, and you’re maintaining a distance of at least eight inches from the surface. A power washer with a pressure rating of 1500 psi is perfectly adequate for routine deck cleaning.

Start by power washing the deck with a suitable composite cleaning solution if necessary, ensuring an even application, then rinse thoroughly. Afterward, allow the decking to air dry naturally.

Using a power washer with higher pressure ratings or narrow nozzles risks exceeding the structural limits of the decking material, which can cause irreparable damage and void the warranty.

Dealing with Different Cleaning Issues On Your Composite Deck

Composite decks can collect different kinds of dirt, requiring specific cleaning methods. Depending on the nature and source of the contamination, there are various techniques to safely and effectively clean composite decks. Here is a detailed look at the best way to clean a composite deck, including early-generation and high-performance Trex® composite.

High-Performance Composite Decking: “TRANSCEND®, ENHANCE®, SELECT®”
DIRT AND DEBRIS	Clean the affected area with a hose to eliminate surface debris. Then, use warm, soapy water and a soft bristle brush to remove dirt and debris from the embossing pattern.
CONCRETE, CEMENT, MORTAR, OR STUCCO DUST	Eliminate particles from the decking surface by employing Sakrete™ Concrete Dissolver.
HARD WATER STAINING	In most cases, white vinegar can effectively remove these deposits from decking surfaces. After cleaning, it's important to rinse thoroughly, avoiding the use of hard water if possible. If hard water is necessary, drying with a cloth or using a blower can prevent water spots. Additionally, for stubborn hard water stains, a deck brightener product may be helpful in achieving a thorough clean.
TANNINS DUE TO DEBRIS	Clear the deck of any debris using a hose or brush. After ensuring the deck surface is dry, follow the manufacturer's instructions to apply a deck brightener. These products typically contain oxalic acid, which effectively removes tannins.
ICE AND SNOW	To clear snow from the deck, use a plastic shovel. Utilize calcium chloride or rock salt to melt snow and ice effectively off the deck.
OIL, GREASE, AND FOOD	Promptly remove any food spills. To uphold the stain warranty, ensure the surface is cleaned within seven days. To clean, spray with a hose and use warm, soapy water along with a soft bristle brush to remove spills from the embossing pattern.
MOLD AND MILDEW	Leaving debris like pollen and dirt on the deck surface can provide a food source for mold to thrive on the biofilm. It's advisable to use warm, soapy water, a hose, and a soft bristle brush to remove both the food source and mold.

Early-Generation Composite Decking: “Trex Accents®, Trex Origins®, Trex Contours®”
DIRT AND DEBRIS	To rid the deck of dirt and debris, simply clean it with soap and water.
WATER SPOTS, LEAF STAINING, AND WOOD TANNINS	Tannin leaching is a natural process in Trex and other wood-based products. You should allow for a minimum of 12 weeks for normal weathering to occur. Alternatively, you can accelerate this process by using a product containing oxalic or phosphoric acid, commonly referred to as Deck Brightener.
ICE AND SNOW	You can use calcium chloride or rock salt, commonly found in home centers, to melt ice on Trex decking. Rinse off the residue as soon as possible. Exercise caution when clearing snow or ice with a snow shovel, and always avoid using a metal snow shovel on a Trex deck. Metal shovels may scratch the deck, and such damage is not covered under warranty.
RUST STAINS, GROUND-IN DIRT AND GRIME, AND PIGMENT STAINING	Use a cleaning solution containing oxalic or phosphoric acid, or Deck Brightener, to lighten or eliminate rust or dirt stains. Allow the product to sit on the stain for 10-15 minutes before rinsing.
OIL/GREASE/ FOOD	Immediately rinse the stain with hot water. Follow the instructions for using Pour-N-Restore® on any residual stain. It's advisable to test it in a small area first, as Pour-N-Restore may remove some colorant from the decking surface.
MOLD AND MILDEW	Clean your deck regularly twice a year to avoid the accumulation of pollen and other debris, which can promote mold growth. For specific cleaning instructions, consult the Mold Technical Bulletin. Please note: Trex Escapes® can be efficiently cleaned using a hose, warm, soapy water, and a soft bristle brush.

Composite Decking: Before and After Cleaning

The innovative design of Trex® composite materials ensures you can enjoy your deck for years to come without worry. The simple and straightforward techniques to clean a composite deck allow you to relax and admire the vibrant hues and deep grains of your sparkling clean deck in no time at all. The striking transformation of before vs. after composite deck cleaning is truly remarkable, especially considering the minimal effort required.

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