Foundation (engineering)
Foundations are designed to have an adequate load capacity depending on the type of subsoil/rock supporting the foundation by a geotechnical engineer, and the footing itself may be designed structurally by a structural engineer. The primary design concerns are settlement and bearing capacity. When considering settlement, total settlement and differential settlement is normally considered. Differential settlement is when one part of a foundation settles more than another part. This can cause problems to the structure which the foundation is supporting. Expansive clay soils can also cause problems.
Earth shelter
Typically earth sheltered structures are more costly to build compared to a regular house. This is due in part to the cost of excavating the earth, having to use structural materials in the walls and the roof which withstand greater load, and increased expense on waterproofing. Many financial institutions outright exclude financing on earth-berm homes or require this type of property to be common for the area. However, as with other types of buildings the cost of construction varies greatly. For example homes built in the style of Oehler would tend to be significantly cheaper than regular houses since he emphasizes the owner(s) doing much of the excavation and work themself and using recycled materials for windows for example.