The answer to 'why is my soffit sagging' is that a sagging soffit is often caused by loose or damaged fasteners, deteriorating wood, or excess weight on the soffit. The soffit is the underside of the roof overhang, and if it starts to sag, it can indicate a structural issue that needs to be addressed.
Some common causes of a sagging soffit include water damage, poor installation, and heavy items like gutters or lights being improperly mounted. Over time, the fasteners that hold the soffit in place can come loose, allowing the soffit to sag. Additionally, if the wood framing or boards that make up the soffit start to rot or deteriorate, it can cause the soffit to lose its structural integrity and start to sag.