Duncanville is a city in Dallas County, Texas (USA). Duncanville’s population was 36,081 at the 2000 census, and estimated at 42,500 in 2008. Duncanville is a suburb of Dallas and is part of the Best Southwest area, which includes Duncanville, Cedar Hill, DeSoto, and Lancaster. ~ Wikipedia
If you would like more information on foundation repair projects in Duncanville then here is a resource to help you understand various requirements by the city.
Stratum Foundation Repair also has created several videos showing examples of foundation problems, such as visible cracks. You are welcome to watch our videos at this link.
Here is one of the videos which may give you a better example of a residential property with foundation-related problems: