Simple rule: pressure wash concrete, soft wash everything else. That's 90% of the answer. The other 10% — where it gets tricky, where people do real damage with rental machines — is below.
What each actually does
Pressure washing
High-pressure water — often 2,500–4,000 PSI — blasted at the surface. The physical force of the water does the cleaning. Fast, aggressive, effective on hard surfaces. Will destroy anything softer than concrete.
Soft washing
Low-pressure water (think garden hose strength) combined with cleaning solution — usually a mix of detergents and diluted sodium hypochlorite that kills algae, mildew, and moss. The chemicals do the cleaning. Gentle enough for paint, shingles, and siding.
The rule by surface
Pressure Wash
- Concrete driveways
- Concrete patios
- Brick pavers
- Most unsealed brick
- Metal gates/fencing
- Outdoor furniture (cautiously)
Soft Wash
- Roof shingles
- Vinyl siding
- Painted wood siding
- Stucco
- Cedar shake
- Screens and window frames
- Deck surfaces (usually)
What happens when people get it wrong
This is the stuff we see on Utah County homes every week:
Pressure washing vinyl siding
Blows water up behind the panels, where it soaks into the sheathing and insulation. Mold shows up in the wall cavity six months later. Siding panels crack, warp, or pop off entirely. We've had to replace full siding walls from this.
Pressure washing stucco
Strips the top finish layer. The stucco starts flaking within a year. Repair is expensive — matching stucco texture is an art.
Pressure washing roof shingles
Blows the granules off the shingles. Granules are what protect the shingle from UV — once they're gone, the shingle dies fast. You can cut your roof's remaining life in half with one aggressive pressure wash.
Pressure washing painted wood trim
Strips paint. Gouges soft wood. You'll be repainting.
Soft washing a driveway
Not dangerous but useless. The chemicals don't remove the oil stains, tire marks, and embedded grime that make driveways look bad. You want pressure here.
The Utah-specific angle
A few things about Utah make this more important than in some parts of the country:
- Stucco is everywhere. Most Utah County homes have at least some stucco. It's especially common on newer builds in Lehi, Saratoga Springs, and Eagle Mountain. Never pressure wash it.
- Cedar shake is common on higher-end homes. Alpine, Highland, and the foothill properties in Provo often have cedar. Pressure washing destroys it fast.
- Hard water means algae grows anywhere shaded. North-facing siding and roof sections develop black streaks and green algae. That's exactly what soft-wash chemicals are designed for.
- Asphalt shingles dry out fast in Utah's sun. They're more brittle than in humid climates. Pressure on them is worse here than most places.
If you're renting a pressure washer, please read this
Rental machines at Home Depot run 3,000+ PSI. That's enough to strip paint, shred siding, and cut through skin. If you rent one, use it for concrete only. Do not aim it at anything vertical on your house.
We're not being dramatic. Half our pressure washing revenue in Utah County comes from fixing DIY pressure wash damage.
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