Cleaning Composite Decking: Complete Care Guide

The Low-Maintenance Myth of Composite Decking

When you invested in composite decking for your Jacksonville home, you probably expected it to be virtually maintenance-free. The marketing materials certainly suggest that.

But the reality is that composite decking — including popular brands like Trex, TimberTech, and Fiberon — requires regular cleaning to maintain its appearance and performance. In Jacksonville's humid climate, composite decks are susceptible to mold, mildew, and algae growth, and the wood fibers in many composite products can absorb stains and moisture that lead to permanent discoloration.

At Clean Fix Jax, we clean and maintain composite decks throughout Duval County, and we've seen what happens when composite decking is neglected — and when it's cleaned with the wrong products. Here's the complete guide to keeping your composite deck looking its best.

Understanding Composite Decking Materials

First-Generation Composite (Wood Flour + Plastic)

Early composite decking products, installed in many Jacksonville homes between 2000 and 2010, contain a high percentage of wood flour (30-50%) mixed with polyethylene plastic. These products are the most vulnerable to staining, mold growth, and fading because the wood fibers absorb moisture and provide nutrients for biological growth.

If your composite deck has a noticeably faded or mottled appearance, it's likely first-generation composite that requires more aggressive maintenance.

Capped Composite

Most composite decking sold today is capped — meaning the composite core is wrapped in a durable polymer shell that provides superior stain, fade, and mold resistance. Capped composite products like Trex Transcend and TimberTech Pro are significantly easier to clean and maintain than uncapped products.

However, the caps can still accumulate dirt, pollen, and biological growth on the surface that requires regular cleaning.

PVC Decking

PVC decking contains no wood fibers at all, making it the most resistant to mold, mildew, and staining. Products like TimberTech Legacy and AZEK Deck are popular in coastal Jacksonville homes near Jacksonville Beach where salt air and humidity are extreme.

PVC decking still requires cleaning but is the most forgiving of the three types.

Proper Cleaning Methods for Composite Decking

Regular Maintenance Cleaning

For routine maintenance, sweep your composite deck regularly and clean it with a mild soap solution twice per year:

• Sweep or blow off debris weekly to prevent moisture trapping and staining
• Wash with dish soap and warm water — 2 tablespoons dish soap per gallon of water. Use a soft-bristle brush on an extension pole and scrub in the direction of the grain pattern
• Rinse thoroughly with a garden hose. Don't use a pressure washer for routine maintenance

Deep Cleaning for Mold and Mildew

Jacksonville's humidity makes mold and mildew growth on composite decking a constant battle. For removal:

• Use a composite deck cleaner specifically formulated for composite materials — products like DeckMax, Corte Clean, or Simple Green Deck & Fence Cleaner
• Apply with a pump sprayer and allow 10-15 minutes of dwell time
• Scrub with a soft-bristle brush — never use wire brushes, steel wool, or abrasive scrub pads that will damage the surface
• Rinse thoroughly with a garden hose or pressure washer at a maximum of 1,500 PSI with a fan tip held at least 12 inches from the surface

Products to NEVER Use on Composite Decking

• Bleach (sodium hypochlorite): While effective at killing mold, bleach breaks down the wood fibers in composite decking and causes permanent fading and surface deterioration. Many manufacturers will void your warranty if they detect bleach damage
• Chlorine-based cleaners: Similar to bleach, chlorine damages the composite material and voids warranties
• Acetone or other solvents: These dissolve the plastic components in composite decking
• Pressure washing above 1,500 PSI: High pressure can etch the surface, remove the protective cap on capped composites, and void your warranty
• Sanding or grinding: Composite decking cannot be sanded like wood — sanding removes the protective surface layer and exposes the composite core to staining and moisture

Treating Common Composite Deck Stains

• Oil and grease: Apply an absorbent (kitty litter or cornstarch) immediately, let sit 30 minutes, sweep up, then clean with a degreasing soap. Food oils from grilling are the most common cause of permanent composite deck staining
• Rust stains: Use a rust remover specifically formulated for composite decking. Standard rust removers may damage the surface
• Berry and leaf stains: These organic stains respond well to composite deck cleaners with oxidizing agents. Apply, let dwell, scrub, and rinse
• Ice melt residue: While Jacksonville rarely needs ice melt, calcium chloride products can leave white residue on composite decking. Rinse thoroughly with water

Preventing Damage to Composite Decking

• Use grill mats under your outdoor grill to catch grease and food spills — the number one cause of permanent composite deck staining
• Move furniture periodically to prevent uneven fading from UV exposure
• Clean spills immediately — composite decking is more stain-resistant than wood, but stains that sit become permanent
• Keep gutters clean to prevent water from dumping onto your deck surface, which promotes biological growth
• Ensure proper drainage beneath the deck to prevent moisture from being trapped against the underside of the boards

Professional Composite Deck Cleaning in Jacksonville

At Clean Fix Jax, our deck cleaning service uses manufacturer-approved products and techniques that clean your composite deck without voiding the warranty. Contact us for a free estimate.

We serve Jacksonville, Orange Park, St. Augustine, and all of Northeast Florida. Visit our FAQ or explore our services or read more on our blog.