The answer to 'why is my flat roof sagging' is that a sagging flat roof is often caused by structural issues or water damage. Flat roofs are more prone to sagging over time due to the weight of accumulated water, snow, or debris, as well as natural settling and deterioration of the roofing materials.
Some common causes of a sagging flat roof include improper installation, poor drainage, rotting roof joists or trusses, and excess weight from things like HVAC units or solar panels. Symptoms of a sagging roof include visible dips or depressions, cracks in the roofing material, and interior water stains or leaks. If left unaddressed, a sagging roof can lead to more serious structural problems and potential collapse.