Never use a zero-degree tip on wood

A zero-degree pressure washer tip can gouge, splinter, and leave permanent marks on wood, so don’t use it on decks, fences, siding, or other wood surfaces. Choose a wider spray pattern, start with the lowest effective pressure, and test an inconspicuous area before cleaning the whole surface.

Why a zero-degree tip damages wood

A zero-degree tip concentrates the washer’s output into a narrow stream instead of spreading it over a wider area. That concentrated force can cut into wood fibers, strip paint or stain, raise the grain, and leave visible stripes or gouges. Softer, weathered, cracked, or already damaged wood is especially vulnerable.

The damage can happen quickly, even if you think you’re holding the wand at a safe distance. A red nozzle is commonly used to identify a zero-degree tip, but color conventions can vary; check the nozzle marking and your washer’s manual.

Choose a wider spray and start gently

For wood, use a wider fan pattern—often a 25- or 40-degree tip—and the lowest pressure that removes the dirt. A wider tip spreads the spray, but it does not make every pressure washer or cleaning approach safe for every surface. Follow the washer and nozzle manufacturers’ guidance.

If your washer has adjustable pressure, start low. If it does not, increase your working distance and test carefully. Keep the nozzle moving, avoid lingering in one spot, and work with the grain where practical. Stop if the wood fibers begin to lift or the surface looks fuzzy, striped, or etched.

Clean wood without gouging it

1. Check the washer manual for suitable nozzles and instructions for wood surfaces. Make sure the nozzle is compatible with your machine.
2. Clear loose debris first. If using detergent, choose one labeled for the surface and follow its directions and the washer manufacturer’s instructions.
3. With the washer off and pressure relieved, install the wider-angle nozzle according to the manual.
4. Test a hidden area using a low-pressure setting or a greater distance. Let the area dry before judging the result, since wet wood can hide marks.
5. Work in manageable sections with steady, overlapping passes. Keep the spray moving and use only as much pressure as needed.
6. Stop if the finish lifts or the wood begins to splinter, fur, or show spray lines. Switch to a gentler method, such as brushing, rather than trying to remove marks with more pressure.

For delicate, old, or valuable wood, hand cleaning may be the safer choice. If a surface has already been gouged, further pressure washing is unlikely to fix it and may make the damage worse.