The answer to 'roof decking algae growth' is that algae growth on roof decking is a common problem caused by moisture, lack of sunlight, and poor ventilation. Symptoms include green, slimy patches on the roof decking that can lead to wood rot and structural damage if left untreated. The solution typically involves cleaning the affected areas, improving ventilation, and applying a fungicide or algaecide treatment.
In many cases, DIY roof maintenance and cleaning can address minor algae growth. However, if the problem is widespread or the roof decking is severely damaged, it's best to call a professional roofing contractor to inspect the roof and determine the best course of action.