Structural Secrets : Unveiling The Key Elements That Define A Reliable Building

Introduction

Buildings are a vital part of human life as they provide shelter and space for various activities. They serve diverse purposes, including residential buildings, offices, commercials, and more. With their varied sizes, shapes, and styles, buildings range from small residential houses to large commercial skyscrapers and iconic landmarks.

Depending on requirements, safety, aesthetics, and economy, they are constructed using various materials such as concrete, steel, wood, etc., to fulfill specific functions. The construction process involves meticulous planning, architectural design, structural engineering, and adherence to building codes and regulations, ensuring that they are safe, sustainable, and durable for their intended purpose.

In this blog, basic requirements that are essential for construction and maintenance of a building are presented and explained.

Basic Elements of Building :

A) Foundation :

Foundation is a substructure that serves a major role in the whole structure because it transfers the weight of the structure to the ground surface. Foundations can be of two types :

Shallow Foundation : When the width > depth of foundation, such structure is called shallow foundation. Examples : strip footing, isolated footing, strap footing, combined footing, raft foundation etc.
Deep Foundation : When the width < depth of foundation, such structure is called deep foundation. Examples : pile foundation, caissons, well foundation, Pneumatic caissons etc.

Foundation serves various functions such as, transmitting load of the structure to the ground, preventing lateral movement of a building, preventing overturning due to lateral forces and facilitate level surface for the structure.

B) Plinth

The function of plinth is to keep ground floor above ground level i.e. free from dampness.
It is usually made of stone masonry, however in case of foundations on pile, a plinth beam is cast to support wall above floor level.
A Damp Proof Course (DPC) of 75 mm thick plain concrete is provided at the top of plinth.
The height of plinth should not be less than 450 mm.

C) Walls and Columns

The primary function of walls and columns in a building is to bear the load of the structure and transfer it vertically downwards to the foundation. However, these essential components serve several other important purposes as well:

Walls divide the building’s interior into separate compartments, creating distinct rooms and spaces. This division allows for organized usage of the building and ensures that different activities can be carried out in designated areas. Additionally, walls provide privacy to occupants by separating rooms from one another.

Walls play a crucial role in providing security by acting as a physical barrier against unauthorized entry, burglary, and other intrusions. They safeguard the occupants and their belongings from external threats.
Well-insulated walls help in regulating the internal temperature of the building. During winter, they retain heat within the enclosed spaces, keeping the interior warm. Conversely, in summer, they prevent excessive heat from entering, contributing to a cooler indoor environment.

D) Sills, Lintels and Chejjas

Sill is a plain concrete course placed over masonry such that a window frame can be placed over. It is generally 50 mm to 75 mm thick.
Lintels are kind of stone or R.C.C beams provided over door and window openings to transfer th transverse load such doors and windows are not stressed unduly. The width of lintels is equal to the width of wall while thickness to be provided depends upon the opening size.
Chejja are cantilever structure i.e. projected outside the wall to protect doors and windows from rain. They are usually made of R.C.C., however for low cost buildings, stone slabs are provided. The projection of chajjas usually varies from 600 mm to 800 mm.

E) Doors and Windows

The function of a door is to provide access to buildings and facilitate easy access to various parts of a building. Generally, the size of the door used is 80 x 36 inches. The size of doors may vary based on applications.
Windows are openings provided at various locations in a building to get light and ventilation. They are generally located at a height of 0.75 m to 0.9 m from floor level.

F) Floor

Floors are a crucial component of any building, providing functional and usable spaces for its occupants.
The ground floor construction begins by filling it with brick bats, waste stones, and gravel, ensuring proper compaction. A 100 mm sand layer is placed on top of this base.
A 100 mm thick layer of lean concrete with a mix ratio of 1:4:8 is laid on the prepared ground floor. Additionally, a damp-proof course may be incorporated to prevent moisture-related issues.
The finishing of the floor is tailored to the owner’s preferences and requirements. A 20 to 25 mm thick rich mortar course finished with red oxide is commonly chosen for more budget-friendly options in a moderate house.
For a more luxurious and expensive floor finish, options like mosaic or marble finishing are preferred.
For other floors in the building, typically made of reinforced concrete (R.C.C.), the finishing is customized based on the owner’s needs and preferences.

G) Roof

The roof serves as the uppermost covering of the building, providing essential protection from the elements. A primary requirement for a roof is that it should be leak-proof to prevent water seepage.
Sloping roofs, such as tiled and A.C. sheet roofs, are effective in providing a leak-proof cover. However, their design does not allow for easy construction of additional floors. Tiled roofs also offer good thermal protection, helping to regulate interior temperatures.
Flat roofs, while not as inherently leak-proof as sloping roofs, offer the advantage of providing space for constructing additional floors. Additionally, a flat roof can serve as a terrace, enhancing the comfort of the building’s occupants. These roofs can also accommodate water tanks conveniently.

H) Stairs and Lifts

Steps are essential for providing convenient access from ground level to the ground floor of a building, particularly at outer wall doors. An ideal size for steps is 250 to 300 mm in width and 150 mm in rise. It’s crucial to maintain uniformity in the size of consecutive steps. The number of steps required depends on the height difference between the ground level and the floor level.
Stairs are designed to provide access between different floors within a building and should consist of steps with uniform sizes. In public buildings, it is mandatory to have lifts to accommodate the convenience of elderly and disabled individuals.
In hostels, buildings with up to G + 3 floors can be constructed without lifts. However, in residential flats, the maximum permissible floors without lifts is limited to G + 2. The location of the lift should be near the entrance for easy accessibility. The size of the lift is determined by the number of users expected during peak hours, and lifts are available with varying capacities ranging from 4 to 20 persons.

I) Finishing

The bottom portion of the slab (ceiling), walls and top of the floor require smooth finishing with plaster.
After plastering, they are provided with whitewash, distemper or paints or tiles.
The function of finishing work is to give a protective cover and improve the aesthetic view.
Finishing work for the plinth consists in pointing while for floor it consists in polishing.

J) Building Services

Major building services encompass water supply, sanitation, drainage works, and electrical supply, along with the construction of cupboards and showcases.

To store water from either municipal supply or tankers, a sump is built within the house property, near the street. Water is then pumped from the sump to overhead tanks placed on or above the roof level, ensuring a continuous water supply throughout the day. Plumbing work is done to distribute water to various areas like the kitchen, bathrooms, water closets, sinks, and garden taps.
To drain rainwater from the roofs, down-take pipes with a minimum diameter of 100 mm are used. These pipes are installed with appropriate slopes to direct rainwater towards the down-take pipe. The pipes are fixed at a slight distance (10 to 15 mm) below the roof surface for efficient water flow.
Sanitary fittings are connected to stoneware pipes using suitable traps and chambers. These stoneware pipes are then linked to the underground municipal drainage lines or the septic tank.
Carpentry works play a significant role in building services, involving the creation of showcases, cupboards, racks, and other storage structures.
Electrical supply is an essential aspect of building services. Adequate electrical points are incorporated within the building to support lighting, fans, and other electric gadgets.

Basic Requirements of a Building

Strength and Stability: Building should be capable of transferring the expected loads in its life period safely to the ground. Design of various structural components like slabs, beams, walls, columns and footing should ensure safety. None of the structural components should buckle, overturn and collapse.
Dimensional Stability: Excessive deformation of structural components give a sense of instability and result into crack in walls, flooring etc. All structural components, should be so designed that deflections do not exceed the permissible values specified in the codes.
Resistance to Dampness: Dampness in a building is a great nuisance and it may reduce the life of the building. Great care should be taken in planning and in the construction of the building to avoid dampness.
Resistance to Fire: Regarding achieving resistance to fire, the basic requirements laid down in the codes are:

(a) the structure should not ignite easily.

(b) building orientation should be such that spread of fire is slow.

Heat Insulation: A building should be so oriented and designed that it insulates interior from heat.
Sound Insulation: Buildings should be planned against outdoor and indoor noises.
Protection from Termite: Buildings should be protected from termites.
Durability: Each and every component of the building should be durable.
Security against Burglary: This is the basic need the owner of the building expects.
Lighting and Ventilation: For healthy and happy living natural light and ventilations are required. Diffused light and good cross ventilation should be available inside the building.