Soft Wash vs. Pressure Wash: Which Is Right for Your Roof?
For asphalt shingle roofs in the St. Louis area, soft washing is almost always the safer choice. High pressure can strip granules and shorten roof life. Here’s the plain-English difference.
What soft washing is
Soft washing applies a cleaning solution at low pressure so it can dwell, kill algae and lichen at the root, then rinse gently. That’s the standard approach for roof soft washing and for most siding work too.
What high-pressure washing is
Pressure washing uses a concentrated jet of water to blast dirt off hard surfaces. It’s excellent for driveways, sidewalks, and many commercial pads — and the wrong primary tool for shingles.
Why roofs prefer soft wash
Black streaks on Missouri roofs are usually gloeocapsa magma (algae), not “just dirt.” Blasting can remove granules that protect the shingle. Soft wash treats the organism so streaks don’t rebound as fast, while protecting the roof surface.
Shaded roofs in Webster Groves and wooded lots in Town and Country grow streaks faster — soft wash is built for that problem.
When pressure washing still wins
Use higher pressure on concrete, some masonry, and many commercial exteriors where the surface can handle it. A full property visit often combines both: soft wash on the roof/siding, pressure on the drive.
How to choose
If it’s a roof or painted/vinyl siding → soft wash. If it’s a stained driveway or dumpster pad → pressure (or a mix). Unsure? Send photos through our quote form and we’ll recommend the method before we roll a hose.
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