The answer to 'why is my flat roof damaged' is that flat roofs are prone to various issues that can lead to damage over time. Common causes include poor drainage, ponding water, UV exposure, and lack of maintenance. Symptoms may include leaks, cracks, blisters, or sagging in the roof material.
For minor issues, some DIY repairs may be possible, such as patching small holes or sealing cracks. However, more extensive damage or systemic problems often require the expertise of a professional roofing contractor. They can properly diagnose the root cause and recommend the best solution, whether that's roof coating, replacement, or other restorative measures.