Method
Soft wash vs. pressure wash
One uses chemistry at garden-hose pressure. The other uses force. They are not interchangeable, and using the wrong one is how people end up with stripped paint, furred cedar, and permanent wand marks in their concrete.
The short version: if it is alive, soft wash it. If it is bonded to hard flat concrete, pressure wash it. Most houses need both, on different surfaces, in the same visit.
Side by side
| Soft wash | Pressure wash | |
|---|---|---|
| What does the cleaning | Chemistry. A surfactant and a dilute sodium hypochlorite solution kill the organism, then a rinse carries it off. | Force. Water at 2,000–4,000 PSI through a surface cleaner lifts what is bonded to the surface. |
| Pressure at the surface | Roughly garden-hose pressure — under 100 PSI. You could hold your hand in it. | High enough to carve wood and etch concrete if held still or used at the wrong tip. |
| What it is for | Living growth: mildew, black algae, moss, lichen. Anything with roots in the surface. | Bonded dirt: traffic film, grease, tire marks, mineral buildup, old moss on hard flat surfaces. |
| Right surfaces | Stucco, painted siding, cedar shake, composite decking, roofs, natural stone, awnings. | Concrete, sealed pavers, masonry, wood and vinyl fence panels, dumpster pads, commercial flatwork. |
| How long the result lasts | Longer on biological growth, because the organism is killed rather than knocked off. | As long as the surface stays out of traffic. It removes what is there; it does not change the weather. |
| What goes wrong if you pick this one by mistake | Nothing damaging — it simply will not shift oil, tire marks, or bonded traffic film off concrete. | Stripped paint, furred wood grain, cracked stucco, driven water behind siding, permanently etched concrete. |
Which surface gets which
Soft wash these
- Stucco walls with mildew streaks, especially north-facing
- Painted wood siding — clapboard, board-and-batten, T1-11
- Cedar shake and shingle
- Asphalt or tile roof with black streaks
- Composite decking — Trex, TimberTech, capped composite
- Unsealed natural stone, and anything beside landscaping you cannot replace
Pressure wash these
- Concrete driveways, walkways, and patios
- Sealed stone and pavers
- Wood or vinyl fence panels
- Dumpster pads with grease and food residue
- Commercial flatwork — parking aprons and loading zones
- Stamped or colored concrete, at reduced pressure
Four things people have usually been told wrong
“Soft washing is just pressure washing on a low setting”
It is a different machine and a different job. Turning the pressure down on a pressure washer gets you weak pressure and no chemistry, which cleans nothing. Soft washing applies a solution that kills the growth, dwells, and then rinses. The low pressure is a consequence of the method, not the method itself.
“The bleach will kill my plants”
At the dilution used for siding it will not, provided the plantings are pre-wetted and rinsed afterward — which is part of the job, not an upsell. What does kill plants is a concentrated mix left to dry on foliage. Ask any company how they protect landscaping; if the answer is vague, that is the answer.
“Pressure washing is more thorough, so it must be better”
On concrete, yes. On stucco it drives water behind the finish and cracks it, and on painted siding it strips paint whether you intended to or not. Thorough is not the goal — the right result on that specific surface is.
“A roof needs pressure to get the streaks off”
A roof needs the opposite. The black streaking is Gloeocapsa magma, a living organism. Pressure dislodges granules from asphalt shingle and shortens the roof’s life while leaving the organism alive to come back. Soft washing kills it and the streaks fade out over the following weeks.
Questions
- Which one does my house need?
- Almost certainly both, on different surfaces. Siding, roof, and anything painted or porous gets soft washed. The driveway, walkways, patio, and fence get pressure washed. A whole-house visit normally includes both, which is why the quote itemizes by surface rather than quoting one method for the property.
- What does each one cost?
- Both come off the same published rate card. A soft wash house starts at $325 for a single-story home up to 1,500 square feet of wall. Pressure washing a driveway starts at $225. Every job carries a $225 service minimum, and booking a driveway, house wash, and deck together takes 10% off.
- Can pressure washing damage concrete?
- Yes, and it is more common than people expect. Holding the wand too close, using a zero-degree tip, or working on concrete that is already spalling leaves visible wand marks and a furred surface that holds dirt worse than before. A surface cleaner at the right distance is what produces an even result, which is why we use one rather than a wand on open flatwork.
- Will soft washing remove oil stains from my driveway?
- No. Oil needs a degreaser and hot water, and deep-set oil may not come out at all — we tell you that in writing on the quote rather than after the visit. Oil treatment is a priced add-on at $45 per stain.
- Is soft washing safe on painted siding?
- On sound paint, yes — that is exactly what it is for. On failing or chalking paint, no method is safe, because the paint is already releasing. If we find that on site we show you and take it off the quote rather than washing it and handing you a bare wall.
- How often does each one need doing?
- Soft washing is driven by growth, so in Sonoma Valley most homes want it annually and shaded north-facing walls sometimes sooner. Pressure washing is driven by traffic, so driveways are usually annual and commercial flatwork much more often. Recurring plans exist because both come back on a schedule you can predict.
Not sure which your house needs?
Describe the surface over the phone and we will tell you, including when the answer is that it does not need washing at all. Or price it yourself — the calculator asks what the surface is and picks the method for you.