6. Building Components and Its Functions

A building comprises several fundamental structural and architectural elements, each specifically designed to perform a primary function. Together, they ensure the structure remains safe, durable, and comfortable for its occupants. Building construction activities generally start with the lowest part and move upwards, broadly dividing a building into two main categories: the substructure and the superstructure.

1. Substructure (Foundation)

The substructure includes all elements below the ground level that safely transfer the building's load to the earth.

• Foundation: As the lowest and most critical part of the building, it acts as the linkage between the structure and the ground.
• Load Distribution: Safely and evenly distributes the load from the superstructure to the soil.
• Anchorage: Secures the building against movement or overturning due to lateral forces like wind or earthquakes.
• Leveling: Provides a stable, leveled surface for the construction of the superstructure.
• P.C.C. & Earthworks: Utilizes Plain Cement Concrete (P.C.C.) at the trench bottom, supported by a sand layer and compacted earth to prevent future structural settling.

2. Superstructure (Above Ground)

The superstructure is the part of the building constructed above the ground surface, enclosing the usable spaces.

Plinth and Damp Proofing

• Plinth: The portion of the wall between the ground level and the ground floor level, usually constructed of stone masonry. It keeps the ground floor above ground level and free from dampness.
• Plinth Height: Must be at least 450 mm total, and specifically at least 150 mm above the road level to allow for proper underground drainage connections.
• D.P.C. (Damp Proof Course): A horizontal moisture barrier, typically a 75 mm thick plain concrete layer, installed at the top of the plinth to stop water from rising up the walls.

Walls and Columns

• Vertical Framework: Form the primary vertical load-bearing framework, transferring the weight of the roof, floors, and their own self-weight downwards to the foundation.
• Enclosure: Divide the building area into compartments for privacy while providing security against burglary and pests.
• Insulation: Help keep the building's interior warm in winter and cool in summer.
• String Course: A decorative or functional horizontal projection along the exterior wall face between floors.

Floors and Vertical Movement

• Floors: Divide the building into different levels to maximize accommodation. Ground floors are prepared with compacted brick bats, gravel, sand, lean concrete, and D.P.C. The finish (often a 10 cm concrete layer with tile) must be smooth, clean, impervious, and durable.
• Steps: Provide access from the ground level to the ground floor. Ideal dimensions include a 250 mm to 300 mm tread (width) and a 150 mm rise.
• Stairs: Facilitate vertical movement between floors and act as a vital fire-resisting escape route during emergencies.
• Lifts/Elevators: Essential in multi-story and public buildings for accessibility.

Doors, Windows, and Openings

Doors provide connecting links for movement and security, sized to fit the largest passing objects. Windows are primarily for natural light and ventilation, typically positioned 0.75 m to 0.9 m from the floor. In hot and humid regions, the window area should be 15% to 20% of the floor area (or 1 m² of opening for every 30 m³ of inside volume).

Component	Description & Location	Primary Function
Sill	50 mm to 75 mm plain concrete base directly under a window frame	Protects the wall top; prevents the frame from resting on raw masonry
Lintel	R.C.C. or stone beam situated directly above door/window openings	Transfers the heavy load of the upper masonry transversely
Chajja (Weather Shade)	600 mm to 800 mm external horizontal projection	Shields windows and doors from rain and direct sunlight
Reveal	Visible side surface of a door or window opening	Forms the structural perpendicular face of the opening

Roofs and Enclosures

• Roofs: The uppermost portion providing a top cover. It protects against weather elements, offers thermal/sound insulation, and prevents early collapse via fire resistance. Sloping roofs easily shed water, while flat roofs allow for water tanks and future floor additions.
• R.C.C. Slab: Forms the main structural reinforced concrete floor and ceiling element.
• Parapet Wall: A protective low barrier wall built along the edge of the roof terrace.
• Coping: Tops the parapet wall with a slanted or curved finish to shed rainwater.

Finishes and Building Services

• Finishes: Treatments applied to ceilings, walls, and floors (plastering, pointing, painting, polishing). They conceal defective workmanship, protect porous materials from weathering, and improve aesthetics.
• Building Services: The essential systems that make a building functional and habitable. These include water supply, plumbing, sanitation, electrical lighting, and integrated carpentry like built-in cupboards.