If you live in Central Florida, you’ve probably seen dark streaks running down the roofs of homes in your neighborhood. It’s not dirt—and it’s not necessarily mold either. What you’re seeing is most likely algae, and it’s a common issue for homeowners in Florida’s warm, humid climate.

At Eave & Gable Roofing, we’re often asked how to prevent these unsightly stains and whether they can damage your roof. The good news? Algae doesn’t usually cause immediate harm to your shingles, but if left unchecked, it can impact your home’s appearance and lead to long-term issues.

Why Algae Grows on Florida Roofs

Florida’s climate is the perfect environment for algae—especially a type called Gloeocapsa magma. This airborne algae settles on roofs and begins to thrive in areas where moisture lingers, particularly on north-facing slopes or shaded areas beneath trees.

Algae appears as black or dark green streaks, which get worse over time. It can:

• Diminish your home’s curb appeal
• Retain heat, raising your cooling costs
• Trap moisture, contributing to moss or lichen growth

How to Prevent Algae Growth on Your Roof

If you’re replacing your roof, prevention starts with choosing the right materials. There are several ways to combat algae growth effectively:

1. Choose Algae-Resistant Shingles

Many roofing products today include copper or zinc granules that actively resist algae. At Eave & Gable, we recommend and install CertainTeed’s StreakFighter® technology, available on many of their shingles.

CertainTeed shingles with StreakFighter® include embedded copper granules that release ions over time, preventing algae from taking hold. It’s a long-term, built-in solution that keeps your roof looking clean and new for years.

2. Add Metal Strips at the Ridge

Zinc or copper strips can be installed near the roof peak. When it rains, these metals release ions that wash down the roof, helping to inhibit algae growth. This is especially useful in problem-prone areas.

3. Keep Your Roof Clean and Dry

• Trim trees to reduce shade and allow more sunlight to hit the roof
• Keep gutters clean to prevent water buildup
• Periodically clean your roof using a soft-wash system or a professional roof cleaning service (never use high pressure, which can damage shingles)

Why We Recommend CertainTeed Shingles

CertainTeed is one of the most trusted names in roofing, and for good reason. In Florida’s humid climate, their StreakFighter® algae-resistant shingles give homeowners peace of mind by combining performance, beauty, and long-term protection.

Benefits include:

• Long-lasting curb appeal
• Built-in algae resistance
• Warranties that cover algae streaking (varies by product)
• Wide range of colors and styles to match any home

At Eave & Gable, we’ve been installing CertainTeed shingles since our founding, and we’ve seen firsthand how well they perform in Florida conditions.

Ready for a Roof That Stays Clean?

If your roof is already showing signs of algae—or if you’re planning a new roof and want to avoid future stains—contact Eave & Gable Roofing. We’re based in Sanford and serve homeowners across Central Florida, from Orlando to The Villages, Daytona Beach and beyond.

We’ll help you choose the right shingles, install them with care, and make sure your home is protected for decades to come.

Call us today or request a free estimate online to learn more about algae-resistant roofing options.