What's a Superstructure vs. Substructure?

What's a Superstructure vs. Substructure?

The superstructure is the component constructed above ground level, while the substructure is the component built below the ground level. The superstructure may seem superior to the substructure as it is typically much longer than the substructure. However, both parts are critical to the stability of any building type. 

This article discusses the key differences between the superstructure and substructure and their applications in construction.

Table of contents:

What is the superstructure?

Some parts of the superstructure may include;

  • Floors: Floors separate the levels within the superstructure.
  • Beams: These are the horizontal elements within the superstructure that support all the vertical loads. 
  • Lintel: This refers to the area over the doors and windows. It provides support to the wall area over larger openings. The lintel is made from reinforced cement concrete or concrete and brick.
  • Walls: Walls help to provide enclosure and privacy. Walls also carry some of the weight from the beams and slabs.  
  • Roof: The roof protects the inside of the building from the elements such as rain and wind. There are countless roofing options available. However, sloped roofs are recommended in highland areas, while flat roofs work well within the plains.
  • Parapet: Parapets are external walls that extend past the roof slab and are chiefly used to prevent water from pouring over onto the entrance of the building.
  • Columns: These are the vertical structures that hold most of the loads from the superstructure and transfer this weight to the foundation. Columns are essential in tall buildings. 
  • Doors, windows, and other openings: Doors, windows, and other openings above the ground level are considered part of the superstructure.
  • Stairs, ramps, and lifts: Stairs, ramps, and lifts are also part of the superstructure, allowing movement around the building.
what is a substructure

What is substructure? 

The substructure refers to the portion of the building that sits below the ground. The substructure distributes the weight of the building to the ground beneath the building. The superstructure is thus built right against the soil. The substructure can make or break a structure. It is crucial to work with structural engineers to ensure that the piers, support beams, and foundations within the substructure do not collapse. 

The substructure base is constructed using either reinforced cement concrete or plain cement concrete. The cement concrete is covered with bricks or stone and additional concrete to the desired plinth level. A damp-proof course is then laid on top to prevent moisture from penetrating the substructure. 

Differences between superstructure and substructure

SuperstructureSubstructure
The portion of a building built above ground levelThe part of a building built below ground level
May include walls, floors, beams, windows, doors, and columnsIt consists of the foundation, abutment, and pier
Transfers loads from the upper part of the building to the substructureTransfers loads from the superstructure to the soil underneath the building
It covers the portion of the building that is below the plinthIt covers the part of the building from the top of the plinth to the top of the building
Provides living space and protects the building from the elementsIt supports the structure and prevents it from collapsing

Summary

The superstructure and the substructure are essential components of a building construction project. The superstructure is the visible part of a building that sits above ground. It starts from the ground floor to the top of the building, while the substructure is the portion below the soil, that is, the foundation. 

Project managers should not underestimate the importance of the substructure. It is worth spending a significant amount of time building a solid substructure to provide adequate support to the superstructure. It is equally important to work with sound structural engineers to ensure that the supporting columns and foundations within the substructure do not collapse.

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