The answer to 'why is my roof decking algae growth' is that algae growth on roof decking is typically caused by excess moisture and poor ventilation in the attic space. Algae thrive in damp, shaded conditions and can grow on the underside of roof decking, causing discoloration and potential structural damage over time.
Some common symptoms of algae growth include dark green or black discoloration on the decking, a musty odor in the attic, and potentially visible algae growth on the decking surface. This can indicate issues with inadequate attic ventilation, poor insulation, or excessive moisture buildup.