Differential foundation settlement is when a structure’s foundation is settling into the soil unevenly. All structures will settle slightly into the soil after their built. As long as the settlement is uniform, there’s no reason to worry. However, differential settlement is another matter. Differential foundation settlement puts a lot of stress on a foundation because everything is out of plumb. You’ll notice things like sloped floors, cracks in walls, floors, and ceilings, stairstep cracks in brickwork, and doors and windows that don’t open and close properly. See the illustration below for more information.