Foundation damage caused by settling, shifting, or earth movement normally isn’t covered by a regular homeowners policy or even by a rider. These fall under the general umbrella of soil compaction and expansion. In these cases, you’ll probably be stuck paying for the repairs out of your own pocket; typically, a homeowner forks over close to $4,200 to fix foundation problems.
Also, foundation damage caused by a sewer backup isn’t covered by many insurers. However, you can buy a sewer-backup rider for about $50 a year.