Why does my roof have black roof streaks?

Artisan technician inspects roof with black algae 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.

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.

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.

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.

Want to learn more? We offer free online roof consultations. Call 919-906-3791 or click here to schedule an appointment for a free roof inspection.

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