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Understanding and Preventing Roof Algae


2 min read

Jun 20




Identifying Roof Algae

Roof algae, particularly Gloeocapsa magma, often manifests as dark streaks or spots on your roof:

  • Appearance: Dark streaks or spots due to a protective pigmented coating against UV rays.

  • Commonly Affected Materials: Asphalt shingles containing fillers like fiberglass and crushed limestone.

  • Spread: Algae spores are airborne and can easily travel from one roof to another, making it a common neighborhood issue.

Factors Contributing to Algae Growth

Several factors contribute to the proliferation of roof algae:

  • Environmental Conditions: Moisture from frequent rain, high humidity, or improperly draining gutters creates ideal conditions for algae growth.

  • Surrounding Flora: Overhanging trees provide shade and drop debris, which retains moisture on the roof.

Consequences of Roof Algae

While not harmful to humans, roof algae can degrade the protective UV granules on shingles, leading to quicker wear, potential leaks, and a diminished roof lifespan.

Proven Methods for Preventing Roof Algae

Preventing algae growth involves several effective strategies:

  • Metal Ridge Flashing: Install galvanized metal ridge flashing to create an inhospitable environment for algae.

  • Zinc Strips: Place zinc strips near the roof peak. Rain washes zinc particles over the shingles, inhibiting algae growth.

  • Sunlight Exposure: Trim overhanging branches to increase sunlight exposure, reducing moisture and shade.

  • Algae-Resistant Shingles: Use shingles with embedded copper granules for added defense against algae.

  • Chemical Treatments: Apply chemicals like copper sulfate to deter algae growth. Professional application is recommended.

  • Professional Cleaning: Regular cleaning by professionals maintains your roof’s appearance and prevents algae buildup.


Maintaining an algae-free roof is essential for the longevity and aesthetic appeal of your home. By implementing these preventive measures, you can protect your roof from the damaging effects of algae. For expert roof maintenance and algae prevention in Mason, OH, contact Fasto Roofing. Our commitment to excellence ensures your home remains in top condition.

If you want to know about selecting wind-resistant roofs for durability, click here.


2 min read