If the beam is not properly nailed it can also pull loose and this contributes to.
Sagging roof ridge beam.
This may have been caused by any number of factors.
The weight of the roof will create pressure and then the hangers may pull away from their beam causing the walls on the exterior to come outwards to cause a visibly sagging roof line on the top of your roof.
Rafter ties another cause.
Ridge beam or ridge board sagging or damaged roofs may sag because a ridge beam or ridge board is cracked or damaged.
Step 1 the first step is to the basement first.
Straighten out your old house s sagging roof and get rid of those cracks in the wall with these easy to follow steps.