Siding is the biggest visible surface on your home, so when it gets dingy the whole house looks tired. Most of that "dirt" is actually living growth.
What those streaks really are
- Green film: algae, thriving on the shaded, damp side of the house.
- Black streaks: mildew and mold, common under eaves and gutters.
- Chalky residue: oxidized paint or finish breaking down over time.
The right way to clean it
The key is a cleaning solution, not brute force. Soft washing applies a mildewcide at low pressure, kills the growth at the root, and rinses clean — so it stays clean far longer than a quick high-pressure blast that only knocks off the surface. High pressure on siding also risks forcing water behind panels, which you never want.
When cleaning isn't enough
If panels are cracked, warped, or fading unevenly, cleaning won't bring them back — that's a repair or replacement conversation. A good pro will tell you honestly which one you're looking at.