Pressure washing is exactly what it sounds like: water under high pressure, typically 1,500 to 4,000 PSI, used to blast contaminants off hard surfaces. It works well on concrete, brick, and stone, which are surfaces that can handle the force. Driveways, sidewalks, retaining walls. If you want to remove years of embedded grime from a concrete pad, pressure is the right tool.
Soft washing uses low pressure, usually under 500 PSI, combined with a cleaning solution. The solution does the work: it kills mould, mildew, algae, and bacteria at the source rather than physically blasting them off. The result is a cleaner surface that stays clean longer, because the biological growth has been treated rather than just removed from the surface.
The mistake people make, and the mistake some contractors make, is using high pressure on surfaces that can't handle it. Vinyl siding, stucco, wood, and roof shingles are all examples of surfaces that require soft washing. High pressure on vinyl siding can force water behind the panels and into the wall cavity, causing moisture damage that shows up months later. High pressure on asphalt shingles strips the granule coating that protects the shingle from UV exposure.
The right method matters as much as the equipment. We assess each surface before we start and tell you exactly what we're doing and why.
Get a free quote→The other issue with pressure washing organic surfaces is that it doesn't actually solve the problem. If you blast mould off your siding with high pressure, you've removed what's visible. But the spores are still there, and growth returns faster than it would have with soft washing. Soft washing kills the organism. Pressure washing moves it around.
When you're getting quotes for exterior cleaning, ask specifically what method the contractor plans to use on each surface. A professional will give you a clear answer and a reason. Anyone who plans to pressure wash your roof or siding is either inexperienced or not paying attention to what they're cleaning.
