Mudjacking!

[HungLikeJesus]

I think that most of the settling occurred in the first few years after the house was built (~1983). We didn't move in until 1998. There is evidence of cracks in some of the walls, and separation of the bath tubs from the tiles.

You're right - the house is not very well constructed. There's a lot of evidence of that. We're slowly trying to improve it, and there's still a lot to be done.

I believe that problems are partly due to expansive soils:

Expansive soils are soils that expand when water is added, and shrink when they dry out. This continuous change in soil volume can cause homes built on this soil to move unevenly and crack....

Although expansive soils can be found in almost every state and in Canada, the problems related to expansive soils are the most severe and widespread in California, Nevada, Arizona, Colorado, and other western and southern states.

We get a lot of snow in the winter (October to April or May), then it's very dry in the summer.

I need to do a visual inspection of the exterior foundation, but much of it is currently under snow.