Cracks in drywall or plaster are one of the most common signs of foundation and crawl space damage. These cracks can appear on interior walls, ceilings, and even floors. They can range from small hairline cracks to large, jagged cracks that run along the length of a wall. These cracks are caused by shifting foundations or damage to wooden components of the crawl space, which cause the walls to move and separate from each other. 

This movement can also cause doors and windows to stick or not latch properly, as well as floors becoming uneven or bowing. In some cases, these cracks may be accompanied by water intrusion due to damaged foundations letting moisture inside the home.