Eugene, OR
It depends on the surface, not a single preference. Concrete, asphalt, and paver driveways and parking pads can take high pressure. Siding, stucco, painted surfaces, older wood, and most decks need a low-pressure soft wash with cleaning solutions instead.
If the surface is hard and load-bearing like concrete, pressure is fine. If it's a finish -- paint, stain, stucco -- soft washing protects that finish while still removing the buildup underneath it.
Gray weathering, moss and ground-in dirt come off a wood or composite deck with a soft wash, leaving the surface ready for sealing or staining rather than roughed up by high pressure.
