When the framing of the roof is put together quite frequently two of the ceiling rafters will be fixed together as this will create a much longer span.
Sagging roof between rafters.
Also inspect the metal or plywood gusset plates used where your wood meets on a truss.
When sagging gets too severe it can lead to roof collapse and once the roof goes the house won t last for long.
Typically they are lapped and then toe nailed together in its center so that the correct length can be achieved.
Sagging rafters are a sign that a house is in serious trouble.
Grab a flashlight and head up to your attic to inspect your roof rafters and decking specifically those where your roof is sagging.
If the roof sags between the rafters or trusses the most likely cause is sheathing that s too thin for the area it covers.
If your ceiling drywall is sagging between joists sometimes called pillowing it s probably on the top floor and attached to the roof trusses.
Determine where the sag is in your roof in relation to your attic.
The fix here is to replace the thin sheathing with thicker sturdier sheathing.
When you notice a roof sagging in between trusses it is usually the result of a damaged or broken roof rafter.
Sagging rafters can lead to serious problems with the entire roofing system.
Prevent this unfortunate series of events by bracing your rafters to make them sturdy and resistant to snow loads and wind.
A sagging roof line may original from the ceiling s horizontal rafters.
If you notice that there is a visible dip in your roof chances are you have a problem with one or several rafters and you may soon be facing more issues like water leaks bowed out walls or your roof caving in on you.
Half inch drywall can sag if it s hung under roof trusses that are spaced every 24 in.
Here s another view of the same roof shown at the top of the page and you can see that the sagging extends over a large area.
Sagging sheathing between rafters may be due to rot delamination use of fiberboard or other materials that may not perform well over the life of a home or due use of too thin plywood roof decking to start with.
Before fixing the problem however it is important to identify the exact cause of the problem.
If so i bet the installers used 1 2 in.
Other potential causes include damaged roof decking or even an underlying foundation problem.