The answer to 'why is my flat roof algae growth' is that flat roofs are prone to algae buildup due to their horizontal surface and lack of drainage. Algae growth is a common issue that can lead to further roof damage if left untreated. Algae thrives in moist, shaded environments and can discolor the roof surface, retain water, and eventually break down the roofing materials.
Symptoms of algae growth on a flat roof include discoloration, slippery surface, and visible green or black growth. Causes can include poor ventilation, standing water, and lack of sunlight. Solutions may involve cleaning the roof, applying an algaecide, improving drainage, and potentially replacing the roofing materials if the damage is severe.