Generally, there are two major components of a building project which are substructure and superstructure. The substructure is the part of the building that is built below the ground level whereas superstructure is the part of the structure that is constructed above the ground level.

Superstructure

The superstructure is the portion of a building which is constructed above the ground level and it serves the purpose of structure’s intended use. It includes columns, beams, slab upwards including all finishes, door and window schedules, flooring, roofing, lintels, and parapets.

Superstructure and Substructure in a Building
Fig. 1: Superstructure and Substructure in a Building

Substructure

The substructure is the lower part of a building which is constructed below the ground level. The function of substructure is the transfer of loads from the superstructure to the underlying soil. So, the substructure is in direct contact with supporting soil. Substructure involves footing and plinth of a building.

An experienced structural engineer should generate plans and works for the substructure of a building project. Added to that, structural engineers are responsible for computing stresses and loads which are required to be supported by the building under consideration. Lastly, structural engineers need to comprehend how to incorporate support beams, columns and foundations into the substructure plans. 

Table-1 Differences between superstructure and substructure of a building

Superstructure Substructure
Part of a building that constructed above ground level Portion of a building that constructed below ground level
It serves the purpose of building’s intended use It transfers loads received from superstructure to supporting soil
Superstructure elements include walls, columns, beams, doors and windows, etc. Elements of substructure include foundation and plinth.