Assess your project and develop a plan for cleaning that considers what direction the deck drains and the location of fragile objects such as windows and light fixtures which can be shattered by the powerful water stream. Plan to work in the direction that water drains so you're not fighting gravity.
Select a nozzle, or tip, for the project. Nozzles attach to the end of the pressure-washing wand that is connected by a hose to the pressure washer pump and motor. Nozzles determines the water pressure - the smallest angle, or opening, will deliver the most power. Most manufacturers suggest a PSI of 2400 to 2600 for decks and most models include a nozzle specifically for cleaning decks; consult the owner's manual for help selecting the right nozzle.
Attach any accessories, such as extension wands, when you connect the nozzle.
Put on protective eyewear and gloves before starting your pressure washer. Also, check that all connections are tight; a loose nozzle can become a projectile that can hurt people or damage property when you power up.
Start the pressure washer and test the spray. Begin by spraying away from the deck and then slowly point the wand toward it from 3 to 4 feet away. Make a few passes and then stop for a moment to see if the surface is clean. If not, move closer. Make slow, methodical passes to rinse the deck of all dirt and other debris using water only.
After turning the pressure washer off, add a chemical for treating decking; consult the owner's manual for help selecting the right chemical solution. Add the chemical using the injector or special nozzle on the pressure washer. If you won't be applying a chemical solution to the surface, proceed to step 9.
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.
After waiting 5 to 10 minutes to let the solution work, pressure wash the deck again using water to rinse away the chemical.
Allow the deck to dry for 48 hours before staining or painting.
Things You Will Need
- Water Source
- Power source (electric or gas)
- Pressure washer accessories
- Eye protection
- Pressure-washer approved chemicals (as needed)
- Point the pressure-washing wand at a slight downward angle to avoid spraying the surface at a direct angle; this will mitigate the force of the pressure reducing the likelihood of damage.
- Standing too close or using a high-pressure nozzle can damage wood and composite decking. Always start with less pressure and add more as needed.
- Use only pressure washer approved, biodegradable chemicals. Consult your owner's manual about what chemical to use on a particular surface. Non-approved chemicals can damage your pressure washer and non- biodegradable chemicals, such as bleach, will damage the environment.