black streaks on roof shingles

The Algae Defense: Copper-Infused Granules and the Science Behind Stain-Free Rooflines

• September 15, 2026
• admin

In humid, tropical environments, a newly installed sloped roof often faces an aesthetic threat within its first few monsoon cycles: dark, unsightly black streaks cascading down the slopes. Homeowners often mistake these vertical discolorations for industrial soot, road dust, or asphalt bleed-through. In reality, the issue is biological. The culprit is an airborne, photosynthetic cyanobacterium …