Two rooms in a house I own were built on a pad of clay.
This got very wet years ago and caused a separation between walls, which I braced using several steel jibbets and a lot of cement (not pictured). Notice the distortion of the small window frame.
You can see light through the corner, but that has since been filled and the result seems really strong. All those bolts actually penetrate the walls and are supported by metalwork on the outside.
Decent foundations would have worked better though.
