A pressure washer is the ultimate weapon against stains and dirt. With the proper technique, an ordinary home pressure washer can remove years of grime from decks, patios, and furniture in minutes. A power washer will remove any surface-level dirt or stripe off faded paint from deck surfaces or patio roofs without scrubbing. It can even clean house siding without damaging it with a strong pressure stream.
Safety and Preparation
Pressure washing is a wet process. You’ll need safety goggles to protect your eyes from sprays, waterproof shoes, and gloves to keep the detergents from corroding your skin. If you’re using a gas-powered washer, wear hearing protection in case of user error, as gas-powered washers are dangerous when handled improperly.
Select the lowest pressure setting for cleaning wood surfaces, but be prepared to go up if needed. Higher pressure will lead to deep scratches in wood and paint chips that could lead to rust.
Start with a cold water wash, minimizing the water used in the process and preventing the warping of wooded surfaces. A hot wash can cause warped wood, so wait to do it until finished. For best results, use a detergent for cleaning decks and other hard surfaces; it’s available at hardware stores and mom-and-pop shops. If you’re using a citrus-based cleaner, you can dilute the detergent with water, but be careful not to go too far: The detergent is acidic enough to eat through wood.
Clean Your Deck and Patio
If your outdoor surfaces are dirtier than expected, start with an easy-to-clean surface. Wash down a brick, concrete walkway, or asphalt driveway with hot water and detergent, scrubbing heavily to remove dirt. Then move on to your deck and patio.
The key to effective cleaning is to scrub the deck or patio in long strokes using a circular pattern. Stop every few feet and rinse the surface with fresh water, keeping your nozzle as close to the surface as possible. This will reduce spray and damage to the finish. Use a stiff-bristled brush (or even steel wool) for stubborn stains, especially those deep in the wood grain. Avoid scouring pads, which will damage the finish. When in doubt, use water. Grime that you can’t remove with a pressure washer requires a good ol’ scrubbing with elbow grease or a stiff-bristled brush and much more elbow grease.
If you encounter stubborn stains as you work, let the surface dry and try again tomorrow. Repeat until the deck or patio has been scrubbed clean. You should have a smooth, clean surface when you’re done. It may be a little softer than before, but the wood will only be yellow or fade once exposed to the sun for a few days.
Pressure Wash Outdoor Furniture
Once your deck and patio are clean, focus on your furniture. Your patio furniture, like your deck and patio, can be pressure washed on the ground. Cushions are much more of a challenge. If they have removable covers, take them off and wash them separately (but don’t wash down the cushions themselves – you’ll need to go over them with a brush).
Use your lowest pressure setting to remove dirt and stains without damaging the furniture. Move the stream in small circles to avoid gouges in the wood, and start with a clean water wash. You can get away with hot water if the furniture is painted or sealed, but if it’s not, keep it cold. If your furniture has rust or mildew stains, apply bleach to the affected areas and scrub well. Rinse with water, and repeat if needed. Allow the furniture to dry for a few days before you re-coat it with sealant.