Why does my ceiling crack in winter and close in summer?

Reviewed by Preston, Oklahoma foundation repair consultant · Updated 2026-10-14

In short: Truss uplift happens when roof trusses bow upward in cold weather and pull the ceiling up off interior walls. It leaves a crack or gap where ceiling meets wall that usually opens in winter and closes in summer. It can look like foundation heave, but the floor has not moved.

What is a roof truss?

Roof trusses are factory-built triangles of lumber. The sloped top members (top chords) carry the roof, and the flat bottom member (bottom chord) doubles as the ceiling joist that the ceiling drywall is fastened to ⁴. The ends of each truss bear on the exterior walls.

How does truss uplift happen?

The two chords live in different conditions. The bottom chord is buried in ceiling insulation, where it stays warmer and drier, while the top chords are exposed to the ventilated attic air ¹. Wood changes size with moisture, so the two parts of the truss move by different amounts. Published explanations describe the bottom chord shrinking as it dries ¹ and the top chords swelling as they take on moisture ²; either way, the truss arches and its middle rises ¹³. Because the truss ends are held by the exterior walls, the center is pushed upward ³.

Interior partitions do not move with the truss, so the ceiling separates from them and the drywall cracks or screws pop ². A partition fastened to the bottom chord can even be lifted slightly off the floor ¹.

When does it happen?

The cracks typically open in winter and close in summer ³. In summer, both chords reach similar temperature and moisture and the truss returns to its original shape ¹. The cycle may occur only once or recur every year ¹. Juvenile wood from near the center of a tree changes dimension more with moisture than mature wood, which affects how much a given truss moves ¹.

Oklahoma's winter cold sets up the temperature difference between attic air and insulated ceiling. Oklahoma Mesonet stations record air temperature and humidity every 5 minutes in all 77 counties, which can be used to line up crack changes with the season ⁵.

Where does truss uplift show up?

• Cracks along the ceiling-to-wall corner over interior, non-load-bearing partitions, especially walls running across the trusses ³⁴.
• Tape torn through at the ceiling corner, rather than a crack along the edge of the tape, which may point to poor taping instead ³.
• Popping or snapping noises from the ceiling ³.
• In one reported case, cracks appeared at interior partitions but not at exterior walls, where the truss ends bear ⁴.

How can truss uplift be told from foundation heave?

Inspecting the attic framing above the crack is part of diagnosis ³. A floor elevation survey separates the two: truss uplift is in the roof, so the floor stays put. See ceiling-wall separation at interior walls and heave vs settlement.

How is truss uplift usually handled?

Because the truss is moving rather than failing, trade literature describes uplift as a cosmetic problem, not a structural one ¹. Common approaches:

• Let the ceiling float: do not fasten ceiling drywall to the truss near interior partitions. Sources give distances of about 12 to 18 inches ² and 18 inches ⁴.
• Drywall clips or backing angles: support the ceiling edge from the wall so the drywall can flex ¹³.
• Slotted connectors: attach the partition top plate to the truss while allowing vertical movement ¹⁴.
• Trim on one surface only: crown or cornice trim nailed to either the wall or the ceiling, not both, can hide the seasonal gap ³.

Pier work does not address truss uplift because the foundation is not the source. See cosmetic repair only.

Related

• Ceiling-wall separation at interior walls
• Center heave (moisture build-up under slab)
• Material shrinkage and thermal cracking (mimic)
• Nail pops and tape-joint cracks
• Cosmetic repair only
• Elevation surveys