The answer to 'flashing repair sagging' is that sagging flashing is a common roofing issue that can be caused by improper installation, age and weathering, or damage. Symptoms include gaps, cracks, or separations in the flashing that allow water to leak through. Solutions may involve re-securing, replacing, or repairing the flashing.
Flashing repair is a job best left to professional roofers, especially for more complex issues. DIY flashing repair is possible for minor problems, but requires caution and the right tools and materials. Attempting major flashing repairs without experience can lead to further damage or leaks.