We have a home in the Denver, Colorado area that was built about 30
years ago. I'm seeing what appears to be a drywall seam separating on
the cathedral ceiling in our living room. I also see "dimples" above
and below the seam that appear to be drywall nail/screws trying to pull
through. They are along what appears to be a single joist or truss. The
drywall appears to have been installed longways across the joists
(trusses?). I don't see any evidence of water damage and the painted
surface has not broken anywhere yet.

I am not sure how much space exists between the drywall and roof deck,
but I'm guessing it is around 10" to allow for the insulation. Also,
the ceiling pitch appears to be about the same as the roof pitch. The
roof is shingled with wood shakes and there are vents installed about
2/3 of the way up the opposite or back side of the roof--not near the
sagging area.

I'm wondering what kind of contractor I should contact to evaluate the
situation. I don't want to assume it is simply a drywall problem and
just call in the "drywall guy". Nor do I want to assume it is a roof
problem and call in a roofer. I'm guessing a general contractor, but
is there someone else that might be a better "fit"?

Thanks,
Dale