Here's the short version: your house and roof should be soft washed, and your driveway and sidewalks should be pressure washed with a surface cleaner. They're different tools for different jobs, and using the wrong one on the wrong surface is how siding gets ruined and shingle warranties get voided.
What soft washing actually is
Soft washing applies professional cleaning solutions at low pressure — comparable to a garden hose — and lets the chemistry do the work. The solution dissolves dirt and kills the algae, mildew, and bacteria growing on the surface, then everything rinses away gently. Because it kills growth at the root instead of blasting the visible layer off, results last considerably longer than pressure washing alone.
What pressure washing is for
Pressure washing uses mechanical force, and hard, ground-level concrete is built to take it. Professional crews use enclosed rotary surface cleaners rather than a bare wand, which is why professional results come out even instead of striped with overlapping wand marks.
Why you should never pressure wash siding or roofs
High pressure forces water behind siding and into wall cavities, chips paint, etches soft Austin limestone, and shreds window screens. On asphalt shingles it strips the protective granules — the layer that makes a shingle a shingle — and most manufacturers explicitly void warranties for pressure-washed roofs. Those black streaks on Austin roofs are algae feeding on the shingles' limestone filler; soft washing kills the algae completely without touching the granules.
The Austin factor
Central Texas humidity feeds algae and mildew on shaded north-facing walls, cedar pollen coats everything from December through February, and our limestone-rich water leaves mineral spots wherever sprinklers hit. A soft wash handles all of it in one visit — and because the treatment keeps working after the crew leaves, most Austin homes stay visibly clean for one to two years.
The bottom line
If a company shows up planning to pressure wash your whole house or your roof, that's a red flag worth acting on. The right answer for nearly every Austin home: soft wash the structure, surface-clean the flatwork.