Preparing your Deck for Pressure Washing
- Remove any loose articles that may become projectiles when pushed by the pressure washer jet.
- Plan to work in the direction that water drains so you’re not fighting gravity.
- Do not use a hot water pressure washer on your deck.
- Nozzles determine the water pressure – the smallest angle, or opening, will deliver the most power.
- The pressure needed for pressure washing your deck will be around 2000 PSI and the best tip for the job is a wide-angle tip of 25 to 40 degrees to create a wider spray to protect the wood from damage.
Pressure Washing Deck Technique
- Wear protective eyewear and gloves.
- Test the pressure washer on some old boards or a hidden side of the deck to make sure that the pressure is adjusted correctly and the spray will not cause any damage to wood.
- Keep your nozzle about a foot away from the deck.
- Practice making a swinging motion back and forth like a pendulum with the spray up, down, and up again away from the surface. With this motion you will avoid leaving marks on the deck were the cleaning stroke starts.
How to Pressure Wash your Deck
- Make slow, methodical passes to rinse the deck of all dirt and other debris using water only.
- If you have a lot of dirt and grime to clean up, consider adding an attachment like a floor brush.
- Keep the jet in motion at all times to avoid marking the surface where you start and stop. If a stain does not come off on the first try, keep passing over it until it dissolves.
- Turn the pressure washer off to add a chemical solution for treating decks.
Choosing the Right Cleaner
- You should always use a cleaning solution for your deck, even when it doesn’t look too dirty.
- Choosing the right power washing chemicals will be critical to obtaining good results when you clean your deck.
- Do not use bleach as it will not only discolor your deck but it may damage the pressure washing equipment.
- There are some pressure washer chemicals that are biodegradable and consumer friendly. These cleaners are gentle on the wood and will not damage the lawn or flower beds around your deck.
- Start the pressure washer and test the spray. Begin by spraying away from the deck and then slowly point the wand toward it from approximately the same distance as when you rinsed the deck. Make slow, methodical passes to coat the deck evenly with the chemical solution.
- Never let the cleaning solution sit on the wood for more than 15 minutes or it will start to dry and leave a residue.
- Always rinse with plenty of fresh water.
- Allow the deck to dry for 48 hours before staining or painting.
Why Stain a Deck?
- Stain protects decking and railings from the damaging effects of sunlight and the elements.
- Water, whether from melting snow or rain, causes wood decks to rot, joints to loosen, and nails to pop.
- Even woods that are resistant to rotting, like cedar and redwood, will rot eventually if they are unprotected from water damage.
- The ultra violet rays from sunlight dry and weaken the wood fibers.
Fungus and mildew may not damage the wood but will discolor it.
How Stain Protects a Deck
- A good deck stain contains additives to retard mildew and penetrates the wood fibers, turning the outer layer of the wood into a protective coating.
- Oil-based stains contain petroleum based solvents which soak into the wood, while water-based stains contain silicone or wax additives to repel water.
- UV protection is usually added with the pigments, although a small amount of UV protective additive is in the better clear stains.