Partition Separation
Question:
I installed roof trusses in my house and dry walled the ceiling to the bottom of the trusses. Now I seem to have a problem with the change of the seasons. Where the ceiling meets the interior wall, a gap opens and closes – in winter it opens, in summer it closes. What did I do wrong, how can I correct it and how should the drywall be installed in the first place?
Answer:
It sounds as if you are experiencing a partition separation problem. This can be caused by several factors working either independently or in combination with one another. The possible causes include building settlement, inconsistent framing, moisture effects, deflection and truss movement. The fact the problem appears to be seasonal leads me to believe that moisture is involved. Do you have enough ventilation in the roof plenum? If you do not, the trusses could be arching due to a substantial difference in moisture content between the top and bottom chords. The easiest way to determine whether this is part of the problem is to measure the moisture content of several truss chords with a hand-held moisture meter. You should also consider using a level to check for settlement of bearing walls, headers, beams and floor members. One option to avoid this issue might be to use corner details that allow the gypsum to “float” with any differential movement between the wall and the ceiling. However, it is important that you determine the cause of the problem so that you can pursue a permanent solution rather than simply treating the symptoms.