Roof Sags In Middle

Some roofs sag because of decay to the inside beams and sheathing.

Roof sags in middle.

Use your string line to determine how much the roof need to go up. Decay can occur over time due to a number of reasons including leaks in the roof or leaks from guttering or downpipes wet rot or even insect attacks such as termites damaging the ends of the bearings. In a stick frame non truss sloped roof these issues usually cause the roof ridge to sag in the middle giving it a swayback look but can also cause one side of the roof to sag. Rotten or saturated sheathing can also cause roof lines to sag.

If your rafters are still sagging a bit and it is causing your roof to dish out a little in the center of the roof sides add a 2x4 that goes all the way across the rafters in the center of the length of the rafters. Installing new rafters directly alongside the weak or damaged ones is often enough to correct this problem. A ridge that droops in the middle forming that unintentional western design feature likely is due to undersized rafters and or missing or inadequate internal bracing rafter or collar ties. Additionally if your roofer has used material that is much heavier than your previous roof it can sag for the same reason.

Non foundational reasons for a sagging roof. This is the easiest problem to repair. The home may not be designed to support the weight of this extra roofing material and it will sag.