The answer to 'why is my skylight sagging' is that the most common causes are improper installation, structural damage, or aging materials. Over time, the skylight frame, seals, and glazing can start to sag and pull away from the roof due to wear and tear, poor construction, or damage from weather and leaks.
Symptoms of a sagging skylight include visible gaps between the frame and roof, water leaks, and the skylight appearing uneven or crooked. This can lead to further damage and water intrusion if not addressed. In some cases, the skylight may need to be completely replaced if the damage is severe.