Deck Washing & Restoration: Cedar, Redwood & Composite

Characteristics

Naturally rot-resistant but highly absorbent. Grays and weathers over time as UV breaks down the natural oils. Can splinter when dried out.

Cleaning Method

Low-pressure washing (500–800 PSI) with a wood-safe cleaning solution removes gray weathering, mildew, and algae. The soft wash approach prevents fiber raising and splintering. After cleaning, the wood is typically sealed or stained within 48 hours.

Frequency

Annual cleaning recommended; every 2–3 years for decks with good coverage.

Characteristics

Low maintenance but not maintenance-free. Surface mold, pollen buildup, and organic staining are common. The surface coating can be scratched by high pressure.

Cleaning Method

Manufacturer recommendations vary, but most composites are safely cleaned at 1,200–1,500 PSI with a fan tip, using a mild detergent. Never use a rotating turbo nozzle on composite — it will leave visible marks.

Frequency

Biennial cleaning is typical for most composites; annual for decks under heavy tree canopy.

Characteristics

The most common budget deck material. Prone to cracking, splinting, and mildew staining. Pressure treating slows rot but not biological growth.

Cleaning Method

Standard soft washing or low-pressure cleaning with a mildewcide solution. Surface is typically ready for re-staining within 24–48 hours of cleaning and drying.

Frequency

Annual cleaning is ideal, especially in shaded yards.

Characteristics

Dense, heavy tropical hardwoods used in high-end decking. Extremely durable but can crack if washed incorrectly. Very sensitive to harsh chemicals.

Cleaning Method

Gentle low-pressure washing only. pH-neutral cleaners specifically formulated for dense hardwoods. No sodium hypochlorite — it can accelerate surface oxidation on tropical species.

Frequency

Biennial cleaning; annual oiling recommended to prevent checking (cracking).