Why does my roof have black roof streaks?

Artisan technician inspects roof with black algae roof streaks

Black streaks on your roof? No, your roof isn’t trying out a new look. It’s growing algae.

Luckily, black roof streaks are mainly cosmetic and cause little-to-no damage to your roof. Nonetheless, they aren’t very nice to look at. So what causes roof streaks, and what can you do about them?

Read on for an introductory guide to roof algae!

What causes roof streaks?

Signs of dark roof streaks or discoloration can begin to show approximately five years after an installed roof.

Mistaken for dirt or granule loss, the dark streaks usually appear on the north-facing slope of the roof.

These streaks are commonly a result of algae growth.

Roof streaks are most prominent on roof areas that receive less sunlight.

Shaded roof slopes will hold moisture for a longer period of time.

As a result, your roof becomes an environment for potential algae growth.

The discoloration or streaking is an aesthetic concern. Thankfully, it does not affect the life of the roof system or its waterproofing characteristics.

How do I prevent roof streaks?

Roofers can add zinc strips to a ridge of a roof to prevent algae from forming. Many manufacturers have also started developing and implementing algae-resistant technology to their roofing shingles.

The primary shingle we install – CertainTeed Landmark Shingles – come with StreakFighter technology. The shingles themselves include copper in the granules to protect against algae. They also come with a 10-15 year warranty against blue-green algae.

How do I remove black roof streaks?

Looking to remove the black roof streaks?

There are various solutions you can use to remove the algae growth.

However, like anything we clean, it is a temporary fix.

It is important to use extreme care when attempting to remove discoloration.

Harsh treatments or power washing can harm your roof system and result in granule loss or leakage.

Want to learn more? Schedule a free roof inspection today! We’re here to help however we can. Serving the NC Triangle.

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