Using the wrong method on the wrong surface causes real damage. Here's when to use high pressure — and when soft washing is the only safe option.
The single most common mistake homeowners make when cleaning their exterior is using high-pressure water on surfaces that can't handle it. Pressure washing has its place — but it's not the right tool for every job. Understanding the difference between pressure washing and soft washing can save you from costly repairs.
What Is Pressure Washing?
Pressure washing uses high-velocity water — typically 1,500 to 4,000 PSI — to blast away dirt, stains, gum, moss, and debris. The mechanical force of the water does most of the work. It's fast and highly effective on hard, durable surfaces.
Best surfaces for pressure washing:
- Concrete driveways and sidewalks
- Brick walkways and retaining walls
- Paver patios
- Concrete pool decks
- Metal fencing
- Commercial flat surfaces
What Is Soft Washing?
Soft washing uses low pressure (typically under 500 PSI — comparable to a garden hose) combined with professional cleaning solutions that kill algae, mold, and mildew at the root. Rather than blasting away growth mechanically, it kills it chemically and rinses it away gently.
Best surfaces for soft washing:
- Vinyl, wood, stucco, EIFS, and fiber cement siding
- Asphalt shingle roofs (the only ARMA-recommended method)
- Cedar shake roofing
- Painted surfaces
- Wood decks
- Composite decking
- Screen enclosures and pool cages
Why High Pressure Damages Certain Surfaces
Asphalt shingles are surfaced with granules that protect the asphalt layer beneath from UV degradation. High-pressure water strips those granules off — shortening roof life by years in a single cleaning session. Many roofing manufacturer warranties are void if the roof is pressure washed.
Wood siding absorbs water driven in under pressure, which leads to swelling, cracking, and mold growth behind the surface. Vinyl siding can be cracked or have water forced behind panels, causing moisture problems in wall cavities.
If a contractor shows up to clean your roof with a pressure washer instead of a soft wash system, ask them to stop. Roof warranty voiding and accelerated granule loss are real consequences.
Which Method Does Exterior Experts Use?
We match the method to the surface — every time. For house washing and roof cleaning, we exclusively use soft washing with professional-grade solutions. For driveways, concrete, and hard surfaces, we use commercial surface cleaners at appropriate pressure. We never use high pressure on roofs, siding, or wood.
The Cost Difference
Soft washing typically costs slightly more than basic pressure washing because of the cleaning solutions involved, but the results last longer — algae growth is killed at the root rather than just removed mechanically, so it takes longer to return. When you factor in surface longevity, soft washing is almost always the better value for homes.