The answer to 'why is my roof sagging' is that a sagging roof is often caused by structural issues or excessive weight on the roof. Common causes include old age, water damage, inadequate roof support, or heavy snow/ice buildup. Symptoms of a sagging roof include visible dips or depressions, cracks in the walls or ceilings, and doors/windows that no longer close properly.
If you notice your roof starting to sag, it's important to address the issue promptly to prevent further damage. For minor sagging, you may be able to reinforce the roof structure yourself by adding additional support beams or columns. However, for more significant sagging or structural concerns, it's best to call in a professional roofing contractor to assess the problem and recommend the appropriate repairs.