What soft washing a roof actually means
A roof soft wash applies a cleaning solution at roughly garden-hose pressure. The solution kills the algae, mildew, and mold across the whole surface, the streaks release, and the roof rinses clean with rain and time. No tiles are walked harder than necessary, no granules get blasted off shingles, and nothing gets driven up under the tile line.
High pressure on a roof cracks tiles, strips shingle granules, forces water under the covering, and voids manufacturer guidance. It also does not fix the problem, because the growth grows back from whatever survives. Killing it chemically is both the safe method and the effective one.
While I am up there I will tell you what I see, gutters full, a slipped tile, ponding areas, because you should know. Fixing roof drainage is your roofer's scope; flagging it honestly is mine.
Straight answers
The questions I actually get, answered the way I answer them on the phone.
Will roof cleaning damage my tiles or shingles?
Soft washing will not. The application pressure is about what a hose puts out. The damage stories you hear come from pressure washing, which is exactly what this method exists to avoid.
How long does a roof stay clean?
Typically a few years in this climate, depending on tree cover and shade. Because the treatment kills the growth rather than just knocking the visible part off, it lasts far longer than a pressure rinse would.
Is the roof treatment safe for my plants?
Handled properly, yes. Landscaping around the drip line gets pre-wet and rinsed during and after treatment so runoff never sits on it.