How-to · wood
Soft-wash mindset: chemistry and dwell first, a wide fan second. Wood is not a driveway. The 0° red tip, a turbo nozzle, and a spinning surface cleaner stay off the boards.
This sequence borrows the wide-fan, downstream-soap path from the house-wash kit. It is not a concrete job. Size the hole on the orifice chart if your stamped PSI and GPM sit outside the homeowner-gas band, then keep the fan wide.
The sequence
40° white is the workhorse. Hold standoff — a foot or more — and keep the fan moving with the boards. 25° green only on stubborn spots, and only with even more distance. The 0° red tip and 15° yellow stay in the drawer.
A peroxide house-and-siding concentrate (labeled for wood) goes through a foam cannon, soap tank, or pump sprayer — after the pump. The inlet still sees water. Bleach, toilet cleaner, and oxidizers never go through the pump.
Sweep grit and popped fasteners first. Foam or spray a wet deck, dwell a few minutes, and do not let it bake. Rinse with 40° along the grain so you are not driving water under boards or into the house envelope.
A 15″ surface cleaner is for concrete and pavers. On grooved or weathered wood it gouges, feathers grain, and leaves tiger stripes you cannot sand out in an afternoon. The wand is the tool.
Raised grain is normal. Do not chase it with more PSI. Give the deck time to dry — often a day or two, longer in shade — then sand or stain per the coating you picked. Composite boards follow the maker’s PSI and cleaner notes, which are usually gentler still.
Weathered cedar, pine, and pressure-treated boards want a wide, forgiving fan — the same idea as vinyl siding. White 40° is soap and rinse. Green 25° can lift stubborn algae or gray if you keep distance and keep the wand moving with the grain. Close-range 25°, 15° yellow, and 0° red chew fibers and leave tracks you will see every sunset.
A peroxide house-and-siding concentrate labeled for wood is pump-safe when it never meets the inlet. Foam cannon, soap tank, or pump sprayer — the washer still pumps water. The foam and soap guide is the chemistry path.
Sodium hypochlorite (soft-wash bleach) is a different job and a different risk on wood and landscaping. Do not improvise bleach through the inlet, and do not assume a siding SH mix belongs on a deck.
Surface cleaners earn their keep on broom-finished concrete. On wood they concentrate two spinning jets under a skirt — enough to stripe and splinter. If the pad under the stairs is concrete, that is the driveway how-to and the surface cleaner matrix. The boards stay on the wand.
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Tip set
Simpson Cleaning 80145 3600 PSI Universal Pressure Washer Nozzles, 1/4-Inch Quick Connect, Set of 5Same 3.0-orifice QC pack as the house-wash kit. On wood you use 40° white and 25° green only, with standoff. Never the 0° red or 15° yellow — they will chew grain.
Deck / siding soap
Simple Green Oxy Solve House and Siding Pressure Washer CleanerPeroxide house-and-siding concentrate labeled for wood (and vinyl, brick, stucco). Downstream or foam path only — the pump still sees water.
Foam cannon
Tool Daily Foam Cannon with 1/4 Inch Quick Connector, 1 LiterDwell tool so soap sits on boards instead of blasting them. Wants roughly 2+ GPM. Flush it when you are done.
Full short list and siding danger notes live on the house-wash kit. Chemistry path? See foam cannons and soap. Washing the house instead? How to pressure wash a house. Concrete pad under the stairs? How to pressure wash a driveway.
Charts first
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