Dark streaks on asphalt and metal roofs are often algae and organic growth. Pressure washing can waste water and risk damage. A bleach-free outdoor cleaner applied with a garden sprayer is a common residential approach.
Spray-and-go basics
- Clear loose debris.
- Spray the roof surface evenly with Ready to Use or properly diluted Concentrate.
- Do not rinse for standard treatments. Let weather and time help lift stains.
For roofs and surrounding hardscapes, start with Citra-Shield Ready to Use or Concentrate for larger surfaces.
Need sun-fade defense on related outdoor fabrics or panels? See Citra UV Shield.