Doors and windows out of square. (see below)
Interior doors out of square (pinched on one side, or a gap on the other) go along with interior walls. Exterior doors do not translate automatically in the same logic. The reason is that the pour out strips that go underneath the door frames.
These pour out strips (diagram to the left) are commonly done so that joints between the stem wall and interior floor slab does not run directly under the door threshold. You can see this easily by looking under the door and noticing a cold joint running down each side under the door frame.
When there is floor slab heave, you can see distress where this cold joint is as the stem wall does not move together with the floor slab.
Since the door frame sits on top of the pour out strip and is part of the floor slab, an outside door that is out of square or pinched could equally be a result of footing movement or slab movement.
Windows out of square, on the other hand, almost always indicate footing movement since they rarely sit on top of the interior slab.
It’s worth noting that walls can be patched, and doors shaved off, but usually windows are not replaced for being out of square. As a result, windows are a more consistent sign of footing movement.
To summarize:
Next: Rules of Thumb IX: https://www.foundationaz.com/blog/rules-of-thumb-part-ix-signs-of-stress
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