Roof Truss Uplift: Understanding the Phenomenon

Where is the most common place for cracks to form due to roof truss uplift?

A. above exterior doors and windows
B. at interior wall/ceiling intersections
C. in the bottom chords of roof trusses
D. in the top chords of roof trusses

Answer:

The most common place for cracks to form due to roof truss uplift is at interior wall/ceiling intersections.

Roof truss uplift is a phenomenon that occurs when the top chord of a roof truss is exposed to different climatic conditions than the bottom chord. This typically happens during winter, when the top chord in the attic space cools and contracts while the bottom chord remains at room temperature. The resulting difference in movement can lead to cracks forming in a home or building.

The most common place for these cracks to form is at interior wall/ceiling intersections. This is because the upward motion of the roof truss could cause separation between the truss and the partition wall below. A gap might open up in the ceiling plaster near the wall, appearing as a crack.

Cracks would typically not form above exterior doors and windows, in the bottom chords of roof trusses, or in the top chords of roof trusses due to roof truss uplift. These parts of the structure are not usually subject to the differential movement that can lead to the cracking caused by roof truss uplift.