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.

Pressure-treated decks last 15 to 20 years on average, but with proper maintenance, you could get 40 to 50 years of value from yours. Reseal your deck every one to two years, and replace old or rotted wood as soon as possible to avoid structural damage. Where you live plays a role in the lifespan of your deck. Intense sunlight, rainfall, wind, and hail can reduce the deck’s lifespan.

Yes, it is possible to add an under-deck drainage system to an existing deck by retrofitting it to the structure. This process may require some prep work. For example, many drainage systems are installed on top of the deck joists, which would require you to remove the decking boards and railings first. To avoid this, you could opt for a below-the-joist drainage system. For best results and to ensure proper installation, it is recommended to consult a professional. A pro can inspect your deck, make any necessary repairs, and then install the drainage system correctly.

When deciding if you should use 2x6 or 2x8 deck joists, consider the size of the deck, joist spacing, and materials. Larger decks, larger-spaced joists, and weaker wood all require more support, meaning they need larger joists. For example, 2x8 redwood joists spaced 16 inches apart can only safely span up to 10 feet and 7 inches. On the other hand, 2x10 southern pine joists spaced 12 inches apart can be as big as 16 feet and 2 inches. If you aren’t sure what size joist is best for your project, speak with your deck builder.