Additionally if your roofer has used material that is much heavier than your previous roof it can sag for the same reason.
Roof sagging in middle.
Common flaws include undersized rafters insufficient sheathing or too few rafter or collar ties.
A sagging roof can come in one of a few classic forms each with its own cause.
If you find an infestation of.
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.
Sagging roof lines can originate with the horizontal ceiling rafters.
Once you have your wood in place you need to lay.
The home may not be designed to support the weight of this extra roofing material and it will sag.
Two or more roofs on one structure spell trouble.
Non foundational reasons for a sagging roof.
The first step is to always check the beams so that you can determine their condition.