How to Clean Composite Deck | Care Without Damage

For the full breakdown, see our best Composite Deck Cleaner guide.

Composite decking resists stains and rotting better than wood, but it still collects dirt, pollen, and mildew. Skip the harsh chemicals and wire brushes — the right method keeps the surface looking new and protects your warranty. Most brands follow the same basic process: clear the deck, rinse, scrub with the right cleaner, and rinse again.

What You Need Before You Start

Gather the right tools first so you don’t reach for something that damages the boards. A simple setup works for most decks:

• Broom or leaf blower for loose debris
• Garden hose with a spray nozzle
• Soft-bristle or nylon scrub brush
• Mild dish soap or a composite cleaner approved by your deck’s brand
• Bucket of warm water

Wire brushes, metal scrapers, and stiff bristles scratch the protective cap on composite boards. Once that surface is damaged, stains sink in and the deck looks worn. A soft brush cleans just as well without the risk.

The Step-by-Step Cleaning Process

Clean in small sections so the soap or cleaner never dries on the surface — dried cleaner leaves a filmy haze that’s harder to remove than the original dirt.

Start by removing furniture, planters, and grills. Sweep or blow off leaves and loose dirt, then rinse the deck with a garden hose. Working in one section at a time, apply warm soapy water or your composite cleaner, scrub gently in the direction of the boards’ grain, and rinse thoroughly before moving to the next section. Let the deck dry completely before putting furniture back — trapped moisture under rugs or planters invites mildew.

For deeper cleaning, a pressure washer works well if you stay within safe limits.

What to Use and What to Skip

Composite brands care about which cleaners touch their boards. Trex allows soap-and-water cleaning or gentle pressure washing for its high-performance lines like Transcend and Select, but its early-generation lines (Accents, Origins, Contours and Profiles) need a composite deck cleaner twice a year.

Let it dwell for a few minutes, but never longer than the label allows.

Keeping It Clean Longer

A few habits cut down on how often you need a full cleaning. Sweep or blow off the deck weekly — this prevents organic matter from sitting on the boards and staining. Wipe up spills quickly, especially oil, wine, or grease. During heavy pollen or leaf-drop seasons, an extra rinse every couple of weeks keeps the surface from dulling.

Watch the weather, too. If you just cleaned the deck and a storm blows in, check for mud splatter and plan a quick rinse once things dry rather than letting it sit for weeks. This protects your deck’s appearance and keeps your cleaning routine light.