Soft wash or pressure wash: what your house needs

Two different methods, one name

Exterior cleaning companies generally work with two different methods, even though homeowners often call both of them “pressure washing.”

Pressure washing (sometimes called power washing) sprays plain water at high pressure — often 2,000 pounds per square inch or more — to blast dirt, algae, and stains off a hard surface by force. Soft washing uses water pressure closer to a garden hose, combined with a cleaning solution that loosens algae, mold, and grime chemically instead of physically. The solution does most of the work; the low-pressure rinse mainly washes it away once it has had time to sit.

Neither method is better in general. The right one depends on what you’re cleaning.

Which surfaces suit which method

Vinyl and painted siding. Soft washing is usually the safer choice. High pressure can drive water up under siding panels and around windows and doors, and it can strip or chip paint that isn’t in perfect condition. A soft wash cleans the same algae and mildew without the water intrusion risk.

Roofs. Asphalt shingles are built to shed water, not stand up to a direct high-pressure blast. Pressure washing a roof can lift or strip the granules that protect the shingle underneath, which shortens the roof’s life and can affect a manufacturer’s warranty. A roof soft wash — low pressure plus a cleaning solution — removes the black streaking algae causes without touching the shingle surface with force.

Driveways, walkways, and patios. Concrete is one of the few surfaces where higher pressure is usually the right tool, since it’s dense and made to be walked and driven on. That said, the wrong nozzle or holding the wand too close can still etch the surface or leave “zebra stripes” where the pressure was uneven, especially on stamped, stained, or sealed concrete.

Wood decks and fences. Wood sits in between. Pressure washing can clean a deck effectively, but too much pressure — or too narrow a nozzle held too close — can raise the grain, gouge soft spots, or leave a fuzzy, splintered surface that never looks right again, even after sanding. A wider fan tip, lower pressure, and more passes usually get the job done without the damage.

What can go wrong with too much pressure

• Water forced behind siding or through window and door seals, which can trap moisture and lead to mold inside a wall before it’s ever noticed
• Stripped paint or damaged caulking around trim, windows, and doors
• Lifted or damaged granules on an asphalt roof
• Etching or uneven “striping” on concrete
• Gouged, splintered, or fuzzy-grained wood on a deck or fence
• Damaged plants, mulch, and outdoor furniture from close-range spray or runoff

None of this means pressure washing is the wrong choice for a job — it’s the standard method for concrete, and a light touch works fine on plenty of other surfaces too. The point is matching the pressure, nozzle, and distance to the material, and switching to a soft wash when the surface calls for it.

What these services typically cost

Service	Typical price range
House washing (siding)	$250–$450 a house
Roof soft wash	$350–$650 a roof
Driveway and concrete	$150–$350 a driveway
Deck and fence	$200–$400 a deck

Where these numbers come from: These are indicative ranges we wrote to give you a sense of scale — they aren’t derived from the listings on this site. For ranges built from the prices the listed companies actually charge, see the town and service pages. What you pay will depend on the size of your house, how dirty the surfaces are, how many stories tall it is, and how easy everything is to reach.

Questions to ask a company

• Which method do you plan to use on my siding, roof, driveway, and deck — and why that one?
• What pressure and nozzle do you use on painted surfaces and wood?
• Can you show proof of liability insurance?
• Will you cover or move plants, furniture, and anything else near the work area?
• Is the price based on seeing the house, or a description over the phone?
• How long do you wait between applying the cleaning solution and rinsing it off?

A company that can explain, surface by surface, why it’s choosing one method over the other is usually the one that knows what it’s doing.