Power Washing a Deck
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A power-washed deck looks like new wood. The process strips a year of dirt, mildew, and weathering in an afternoon. The technique matters more than the tools: too much pressure destroys the wood grain, too little leaves the grime behind. Start with the widest nozzle and work your way to more pressure only if needed.
Cost Breakdown
Prep
Sweep loose debris, leaves, and dirt off the deck before wetting anything.
Apply deck cleaner solution evenly before power washing. A $15 pump sprayer covers a deck in 5 minutes.
Washing
An electric pressure washer (1,500-2,000 PSI) is enough for decks. Gas models are more powerful than you need and more likely to damage wood.
Connects to the pressure washer and provides a pre-rinse and final rinse.
Finishing (Optional)
Apply deck stain or sealer after the wood dries (48-72 hours). A 9-inch roller covers flat decking fast.
Cut in stain around railings, posts, and edges where the roller cannot reach.
Consumables and Supplies
These get used up during the project. Always buy these new.
- Deck cleaner/brightener Oxygen bleach-based cleaners (OxiClean, DeckMax) are effective and safe for plants. Avoid chlorine bleach. It damages wood fibers.
- Deck stain or sealer Apply after washing and drying (48-72 hours). Transparent stain shows grain. Semi-transparent hides imperfections. Apply the same day you open the can.
- Plastic sheeting Cover nearby plants before applying cleaner or stain
Safety Gear
- Safety glasses (pressure washer spray bounces back)
- Hearing protection (pressure washer)
- Rubber-soled shoes (deck is slippery when wet)
Before You Buy Anything
Check if your neighbors already have the tools you need. Borrowing saves money, saves storage space, and keeps tools in use instead of collecting dust.
See how FriendsWithTools worksCommon Questions
What PSI should I use on a wood deck?
Stay under 2,000 PSI for softwood decks (pine, cedar). Use the 40-degree or 25-degree fan nozzle and keep the tip 8-12 inches from the surface. Never use the 0-degree (red) nozzle on wood. It will gouge the surface instantly. For composite decking, follow the manufacturer guidelines; most recommend under 1,500 PSI.
How often should I power wash my deck?
Once a year in spring is the standard for most decks. If your deck is in shade and develops mildew faster, twice a year. Always power wash before re-staining or sealing. The new finish needs to bond to clean wood, not dirty wood.