Sticking Doors and Windows: If doors are suddenly hard to open, drag on the floor, or don’t latch properly, the frame may have been pulled out of "square."
Diagonal Wall Cracks: Look for cracks that start at the corners of door and window frames and travel upward at an angle.
Uneven or Sloping Floors: If you feel a "dip" as you walk or notice a ball rolls across the floor on its own, the house may be sinking on one side.
Gaps in the Trim: Watch for crown molding pulling away from the ceiling or baseboards separating from the floor.
Stair-Step Cracks in Brick: One of the most classic signs is a crack in the exterior brick or mortar that looks like a set of stairs.
Gaps Around Window Frames: If the foundation shifts, you may see visible gaps between the window frame and the brickwork.
Leaning or Tilting Chimney: A chimney that is pulling away from the house or leaning is a major indicator of unstable soil underneath.
Cracked Foundation: Large horizontal cracks (wider than 1/4 inch) in the visible concrete foundation are a high-priority warning sign.