The average cost to professionally clean or pressure wash a deck is around $150, with prices typically ranging from $100 to $600. Several factors influence the final price, including the deck's size, material, condition, and how long it has been since its last cleaning. For a smaller deck of about 300 square feet, you might pay around $100. For a larger deck of 1,000 square feet or more, the cost could be closer to $300 to $400. Decks that are very dirty or haven't been cleaned in years may require more time and special detergents, which will increase the price. The deck's material also plays a role. Wood decks often cost more to clean because they require a gentle power washing technique to avoid damage. Composite decks are typically less expensive to clean, and cleaning a metal deck may cost around $100.

Wood decks need to be replaced every 10 to 15 years on average. Natural wood is highly vulnerable to infiltration and damage from moisture, which can occur rapidly due to exposure to outdoor elements. You can protect your deck and maximize its lifespan by sealing it every year or two.

The best way to clean your decking is to clear debris from the gaps between the boards, sweep the surface, rinse it, apply cleaner, rinse again, and let it dry fully. A homemade deck cleaner made of two gallons of warm water and 1/2 cup vinegar is a simple cleaning solution for both wood and composite decking. You can sprinkle baking soda on any spots with mold or mildew, then scrub the area and rinse clean. 

Footings for ground-level decks need to be at least 12 inches deep, and some areas require them to be even deeper. A standard range for deck footings is anywhere from 12 to 48 inches. The minimum footing depth is determined by an area’s frost line and soil conditions. If you’re unsure how deep to install deck footings, check local building codes to find the minimum footing depth in your area.