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.
Bungalow
On a per unit area basis (e.g. per square meter or per square foot), bungalows are more expensive to construct than two-story houses, because a larger foundation and roof area is required for the same living area. The larger foundation will often translate into larger lot size requirements, as well. Due to this, bungalows are typically fully detached from other buildings and do not share a common foundation or party wall: if the homeowner can afford the extra expense of a bungalow relative to a two-story house, they can typically afford to be fully detached as well.