Truss uplift
Seasonal arching of roof trusses that opens a gap between interior partition walls and the ceiling, usually in winter.
What is Truss uplift?
What is Truss uplift?
In a truss, the top chords sit in cold, dry attic air while the bottom chord is buried in insulation and stays warmer and more humid. The differing moisture content makes the bottom chord arch upward in winter, lifting the ceiling away from interior partitions that are not structurally attached to it. The gap closes again in summer. It is a cosmetic and seasonal condition rather than a structural failure, and the standard remedy is a cosmetic one — crown moulding fastened to the ceiling only, so it can float. Recognising it matters because it is easily and expensively misdiagnosed as foundation movement.