Another approach is to give more support to the walls by installing chains attached to the wall plates and linked in the middle with a turnbuckle.
How to pin up saggy roof.
After that use a piece of lumbar strapping to keep the plywood in place until you can get a roofing repair expert to fix it.
When you push it against the backboard you need to twist it and the headliner will stick in place.
Now add collar ties from one side of the rafter to the other.
Additionally if your roofer has used material that is much heavier than your previous roof it can sag for the same reason.
Once you have established how much the roof sag needs to be jacked up lay a 2x4 plate across the ceiling joists and nail directly under the ridge of the roof.
Two or more roofs on one structure spell trouble.
Remove the jack quickly and set the iron onto the entire beam.
Non foundational reasons for a sagging roof.
Depending on the degree of sagging your contractor might need to use jack posts to raise the roof before installing any reinforcement.
Drive the remaining carriage bolts into the two by six rafter and tighten them all up.
Then lower the jack down a little at a time so that the metal can take the weight of the roof.
That s how to fix a sagging roof.
First perform step 2 except keep the string under your beam and off to the side a bit to make room for some framing.
Push up on the plywood until the foam is touching the underside of the roof decking.
Next place your piece of plywood and styrofoam foam side up against the damaged roof decking.
Place the jack back underneath the beam but this time under the iron piece.
Twist pins are a special type of pins that can be termed as the real solution for your sagging headliner.