How to Clean Trex Composite Decking

Step-by-step instructions

Step 1: Identify the Trex generation

Find purchase records, board markings, or installer information to distinguish high-performance Transcend, Enhance, or Select boards from early-generation uncapped composite and from PVC products. The current pressure-washer allowance does not automatically apply to every older Trex surface. When uncertain, use the gentler hose-and-soft-brush method and ask Trex support.

Step 2: Choose a cool cleaning window

Work when boards are cool and direct sun will not dry dirty solution before rinsing. Remove furniture, grills, mats, and planters, then test soap on a hidden area. Protect nearby plants and route runoff responsibly. Do not mix deck cleaners or use solvents, acids, degreasers, or plastic-damaging chemicals without Trex approval.

Step 3: Sweep and hose away loose debris

Clear leaves from boards, gaps, stairs, and drainage routes with a broom or blower. Hose the affected area to remove loose surface dirt. Removing grit before brushing reduces abrasion and prevents leaves and pollen from feeding the biofilm associated with mold growth.

Step 4: Scrub with warm soapy water

Mix mild soap into warm water, wet a manageable section, and gently scrub each board with a soft-bristle brush following the length and embossed grain. Do not use a wire brush or hard abrasive pad. Work railings separately according to their material because aluminum, glass, and composite rails do not share one procedure.

Step 5: Rinse each section thoroughly

Rinse before the dirty solution dries. Trex warns that dried cleaning water can leave a film, so move section by section and flush gaps as you go. On hard-water properties, dry boards with cloths or a blower when practical to limit mineral spotting.

Step 6: Pressure-wash approved high-performance boards cautiously

For Transcend, Enhance, or Select composite decking, Trex permits a pressure washer no greater than 3,100 psi with a fan attachment and soap dispenser. Spray soap, gently brush, then rinse each board with the fan tip at least eight inches away. Never use a narrow jet, linger in one spot, or assume this allowance covers early-generation boards.

Step 7: Treat food, grease, mold, and mildew promptly

Rinse food and grease, then use warm soapy water and a soft brush in the embossing; Trex says spills should be cleaned within seven days to maintain stain-warranty terms. For surface mold or mildew, remove its pollen-and-dirt food source the same way. Avoid chlorine mixtures and generic deck chemicals unless the exact Trex guide approves them.

Step 8: Address hard-water spots and tannins specifically

Trex identifies white vinegar as a general option for mineral deposits, followed by thorough rinsing and drying so hard water does not redeposit. For tannins from organic debris, clear the debris, let the surface dry, and use a deck brightener containing oxalic acid exactly as its manufacturer directs. Test specialty products first.

Step 9: Handle construction dust as a special case

Cement, mortar, concrete, and stucco dust can react on the decking when heated or wet. Protect boards during work and do not simply flood settled dust. Trex recommends Sakrete Concrete Dissolver for affected current boards, used strictly according to its label; contact Trex first when the product generation is unknown.

Step 10: Dry, inspect, and return furniture

Allow the deck and gaps to dry fully, then inspect from several angles for soap film or missed dirt. Rinse again rather than adding more product if film remains. Put furniture and mats back only when dry, using protective feet and airflow so moisture and debris do not remain trapped against the boards.