Understanding Building Drawings: From Foundation to Terrace

The Importance of Building Drawing in Engineering

Drawing is often referred to as the language of engineers. In the context of building construction, drawings provide detailed information about all key elements, including foundations, doors, windows, lintels, arches, roofs, and floors. Additionally, these drawings should cover the placement of sanitary and electrical fittings. Rather than depicting these fittings in their actual form, they are typically represented using symbolic graphical symbols. These symbols are a simplified way to convey complex objects and components that would be challenging to accurately depict on a drawing sheet. The standardized conventional symbols set by the Bureau of Indian Standards (BIS) are used, ensuring consistency and recognition both nationally and internationally.

Understanding the Convention of Cutting a Plan in Building Drawings

A plan is a scaled graphical representation of a structure, such as a building, as projected onto a horizontal plane, typically represented by the plane of the paper on which the plan is drawn. A building comprises various rooms, including toilets, kitchens, and other spaces, all interconnected through corridors, passages, and verandahs. Each room may feature elements like doors, windows, almirahs, and cupboards. To accurately represent these elements on a plan, it is conventionally “cut” at the window sill level. Cutting the plan at this height allows for the inclusion of windows, almirahs, and other features that might be missed if the plan were cut at the plinth level, where the sill of these elements is positioned higher.

Different Types of Building Plans

A complete representation of a building can be achieved through various types of plans, each serving a specific purpose:

1. Floor Plan: This includes the layout of a typical floor, such as the ground floor or first floor.
2. Foundation Plan: This plan details the layout and design of the building’s foundation.
3. Structural Plan: A structural plan outlines the structural elements of a typical floor, highlighting the framework and load-bearing components.
4. Terrace Plan: This plan illustrates the layout and design of the building’s terrace.

Types of Building Plans Explained

1. Typical Floor Plan
   A typical floor plan, whether for the ground floor, first floor, or any other level, is drawn by cutting the plan at the window sill level. This approach ensures that all windows, cupboards, almirahs, and doors on that floor are accurately represented.
2. Foundation Plan
   A foundation plan is created at the foundation level, detailing the various types of foundations used in the building. Common foundation types include:
   • Spread footing for walls
   • Rectangular RCC footing for individual columns
   • Combined RCC footings for two columns
   • Strap footing for two columns
   • Raft foundation for a group of columns
3. Structural Plan of a Typical Floor
   The structural plan of a typical floor includes the location, identification, and details of various structural elements at that floor level. For example, a structural plan might show the layout of the first floor slab in a multi-story RCC (Reinforced Cement Concrete) building.
4. Roof or Terrace Plan
   The terrace plan represents the roof level, highlighting features such as stair cabins, lift cabins (if present), overhead water tanks, and the roof drainage system. It also includes the parapet walls surrounding the roof.

Illustrative Plan

An illustrative plan, such as the one shown in Figure, provides a visual example of various civil, sanitary, and electrical symbols used in building drawings.

Cross-Section in Building Drawings

While a building plan highlights various elements like doors, windows, almirahs, and cupboards on a horizontal plane, a cross-section is essential for depicting the following vertical elements of the structure:

1. Footing
2. Plinth
3. Flooring
4. Lintel
5. Sunshade/Chajjah, balcony, etc. (if applicable)
6. Beam
7. Slab
8. Parapet wall
9. Coping, and more

For example, Figure 1(d) illustrates a typical cross-section that includes several of these features. Similarly, Figure 6 shows a cross-section highlighting the staircase and the sunk floor of a toilet on the upper floor, corresponding to section ABC of Figure 5.