The answer to 'why is my roof decking water stains' is that water stains on the roof decking are typically caused by leaks in the roofing system. These leaks allow water to penetrate through the roof and onto the decking below, causing unsightly water stains and potentially leading to further damage if left unaddressed.
Common causes of roof leaks that can lead to water stains include damaged or missing shingles, cracked flashing, improper roof ventilation, and clogged gutters. Symptoms may include visible water stains, mold or mildew growth, and even sagging or rotting of the decking itself. To address the issue, it's important to identify and repair the root cause of the leak, which may require the expertise of a professional roofing contractor.