Algae, Mold, and Mildew: What’s Actually Growing on Your Jacksonville Home

Algae

Gloeocapsa magma, the blue-green algae responsible for roof streaking, is the most common type Jacksonville homeowners deal with. It thrives in humid, shaded conditions and, on roofs specifically, actually feeds on the limestone filler in asphalt shingles.

Mold

Mold tends to show up as darker, often black or greenish-black patches, commonly in shaded, poorly-ventilated spots like north-facing walls or areas with limited airflow. It can affect both exterior surfaces and, if left unaddressed near entry points, work its way toward interior spaces.

Mildew

Mildew is typically a lighter, more surface-level growth, often appearing as a powdery or fuzzy white-to-gray film. It’s usually easier to remove than established mold but returns quickly in the same humid conditions.

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