The answer to 'flat roof algae growth' is that it is a common issue caused by moisture, shade, and organic debris on flat roofs. Algae growth can lead to roof discoloration, deterioration, and even structural damage if left untreated. The symptoms include green, black, or reddish-brown stains on the roof surface.
To address flat roof algae, the first step is to identify and eliminate the underlying causes. This may involve improving roof drainage, trimming overhanging trees or shrubs, and regularly removing organic debris. For minor algae growth, a DIY solution of bleach, detergent, and water can be effective. However, for more severe or recurring issues, it's best to call in a professional roofing contractor who can properly assess the problem and recommend the appropriate treatment, which may include pressure washing, algaecide application, or even roof replacement in some cases.