A house that has moved, or one that is not built yet.

Signs worth a look

Sticking doors, diagonal cracks, a porch pulling away, or a floor that slopes are reasons to have the structure seen. They are not a diagnosis. Efflorescence — a white salt on masonry — can mean water is moving through the wall. It does not, alone, mean a pier is required.

Crawl spaces

If the floor sags because posts or beams have settled or rotted, the published repair is a helical pier under the load and carpentry on the wood. A dehumidifier does not pick a floor back up. Whether the equipment fits your crawl space is a site question.