Expert: Dave Johnson - 1/4/2008

Question
Dave,

   I have a new construction cathedral ceiling where the new drywall seams
keep cracking.
   The construction is properly engineered on existing foundations and the
drywall was installed correctly. There are no other drywall issues other than
this ceiling.
   The house is in Los Angeles. The room is situated on the north side of the
house. This room is always cooler than the outside temperature.
   I am afraid to continue with the interior finishes until the ceiling issue is
resolved.

   Could this have anything to do with air movement inside the rafters? I
installed ventilated eaves soffit that takes air up to the roof's ridgeline vent.

   I am at a complete loss and would appreciate any advice you could give.

Thank You,

David

Answer
Hi Dave,
I suspect the moisture from the framing has dried and altered the wood enough to break the drywall seams.
Also there is quite a lot of moisture in the drywall finishing and that may have done the same with the rafters/trusses.
If the roof framing is non-trussed (on-site fabricated)
Thwere may also be a certain amount of settling.
The air above the ceiling shouldn't be a problem unless, again, there is excessive moisture from outside causing swelling and shrinking of framing members.
This doesn't solve your problem, but offers  some possible reasons. Need more? just ask.
good luck...
Dave