You should absolutely clean your deck before sealing it. Cleaning before refinishing it is critical. If you don’t remove dirt and debris, you’ll lock these moisture-trapping elements into your wood. This will keep any new sealer from doing its job and lead to failure and costly repairs. Whether you need to sand, power wash, or sandblast depends on its condition.
Whether you seal or stain depends on many factors, including the type of wood, your climate, the deck’s age, and how damaged it is.
Power washing and sealing a deck costs $500 to $1,700, depending on size.
Depending on your climate, you should seal your deck every one to three years.
You can leave a deck untreated, but it’ll rot quickly, and you’ll replace it sooner rather than later. Deck replacement costs $4,000 to $11,500.