If you've ever Googled "pressure washing near me," you've probably seen two terms thrown around as if they're the same thing: pressure washing and soft washing. They're not. Using the wrong one on the wrong surface is one of the fastest ways to damage a house, void a roof warranty, or end up with peeling paint.
Pressure washing: high water pressure, no detergent (usually)
Pressure washing relies on raw water force — typically 2,000 to 4,000 PSI — to blast dirt off hard, durable surfaces. It's the right tool for:
- Concrete driveways, sidewalks, and patios
- Brick walls and unpainted masonry
- Most pool decks and pavers
- Fleet trucks, trailers, and heavy equipment
On these surfaces, paired with a surface cleaner attachment, pressure washing gives you that satisfying "before and after" stripe of clean concrete.
Soft washing: low pressure, professional detergents
Soft washing uses pressures closer to garden-hose levels (under 500 PSI) combined with biodegradable detergents that actually kill the algae, mildew, and bacteria causing the staining. It's the right tool for:
- Vinyl, aluminum, wood, and painted siding
- Asphalt shingle roofs (this matters — see below)
- Stucco, EIFS, and Dryvit
- Screened porches and pool enclosures
Why this matters for your roof
The Asphalt Roofing Manufacturers Association (ARMA) explicitly recommends against high-pressure washing of asphalt shingles. High pressure strips the granules that protect your shingles from UV — and granule loss is the #1 cause of premature roof failure. The black streaks you see on shingles aren't dirt; they're a cyanobacteria called Gloeocapsa magma. The only way to actually remove them is to kill the organism with a soft-wash treatment. Pressure alone just blasts off granules and leaves the algae behind.
The bottom line
A good pressure washing contractor will use both methods, matched to the surface. If a quote you've gotten only mentions "pressure," ask what they plan to use on your siding and roof. The answer will tell you whether they're going to clean your home — or damage it.
Want a free, honest quote from a crew that uses the right method for every surface? Request a quote or call (614) 489-8776.