Types of Bricks Used For Construction In India
What Is Brick?
Bricks are the building blocks of modern masonry structures. Bricks are rectangular blocks of uniform size that are hardened by heating or chemical processes. There are different types of bricks available in the market such as clay bricks or red bricks (1st class bricks, 2nd class bricks, etc.), Bricks are the most basic yet important materials used for building construction in India.
- Cost-efficient
- Easily available
- Highly customizable
- Eco-friendly
- Simple installation
Types of Bricks Used For Construction In India
1. Sun-dried or Unburnt Clay Bricks
Sun-dried or unburnt bricks are less durable and are typically used for temporary structures. The preparation of unburnt bricks involves three steps: clay preparation, molding, and drying. After molding, the bricks are left in sunlight to dry using the heat from the sun. However, since these bricks are not subjected to the high temperatures of a kiln, they are not as strong or durable as burnt bricks. They also have less water resistance and fire resistance. Due to these limitations, unburnt bricks are not suitable for permanent structures but can be used for temporary constructions where durability is not a major concern.
2. Burnt Clay Bricks
Burnt clay bricks are the oldest and most widely used construction material. These superior quality bricks are extensively used in the construction of vital structural members such as walls, columns, foundations, and more. Burnt bricks are classified into four different types, which are as follows:
- First Class Brick
- Second Class Brick
- Third Class Brick
- Fourth Class Brick
- First Class Brick
This category of burnt clay bricks belongs to the highest quality standards. They are table molded and undergo the firing process in kilns. These bricks have a consistent shape, smooth surfaces, and sharp edges. They are known for their exceptional durability and strength, making them highly suitable for various construction applications. These bricks meet all the quality criteria of good bricks, ensuring reliability and longevity in construction projects.
- Second Class Brick
These bricks are of moderate quality and are ground-molded before being burnt in brick kilns. They have an irregular shape and a rough surface, often with hairline cracks. These bricks are typically used in areas where the brickwork will be covered with a coat of plaster. The rough surface provides better adhesion for the plaster, ensuring a strong bond between the brickwork and the plaster layer. While these bricks may not have a smooth and uniform appearance, they serve their purpose well in providing a solid foundation for plastered surfaces.
- Third Class Brick
As the name suggests, these are poor quality bricks which are normally used for structures that are temporarily constructed. Note, these are not suitable for areas that receive a lot of rain. Third Class bricks are molded on the ground and are further burnt in clamps. The surface of this category of bricks are rough and these have edges that are unfair.
- Fourth Class Brick
These bricks are over-burnt, irregular in shape, and have a dark color. They are commonly used as aggregate in concrete for foundations, roads, floors, and other construction applications. Despite their irregular shape, these bricks can be stronger than the first-class bricks due to their compact structure. They provide good stability and strength to the concrete structures in which they are incorporated. These bricks are typically used in areas where appearance is not a primary concern, but strength and durability are essential.
3. Concrete Bricks
Concrete bricks are manufactured using solid concrete, which includes ingredients like cement, sand, coarse aggregates, and water. The sizes of these bricks can be customized to meet specific requirements. They are frequently employed in various applications such as facades, hidden/internal brickwork, fences, and other construction projects. Concrete bricks not only offer excellent strength and durability but also provide an appealing aesthetic appearance. They are known for their versatility and ability to enhance the visual appeal of structures.
4. Fly Ash Bricks
Fly ash brick is a building material that is specifically used in masonry units. It contains class C or class F fly ash (a byproduct of coal burning) and water that is fired at around 1,000 degree Celsius. 
5. Engineering Bricks
Engineering bricks have high compressive strength. These bricks are commonly used for basements where chemical or water attacks are prevalent and for damp proof courses.
6. Hollow Bricks
Hollow bricks are lightweight and insulating bricks that are utilized to reduce the weight and cost of construction, while also enhancing the energy efficiency and comfort of buildings. These bricks are designed with hollow cavities inside, which provide excellent thermal insulation properties. The hollow spaces also make the bricks lighter in weight, making them easier to handle and transport. Hollow bricks are commonly used in construction projects where the focus is on energy efficiency and sustainable building practices. They contribute to better insulation, reduced heat transfer, and improved overall performance of the structure.
The standard brick size is
190mm (length) x 90mm (width) x 90mm (height).
First-class bricks water absorption rate of less than 15%.
Second-class bricks water absorption rate of 16% to 20%.
The formula to calculate the water absorption of bricks is:
Water absorption = ((W2 – W1) / W1) x 100
Where:
- W1 is the weight of the dry brick in grams (g)
- W2 is the weight of the same brick after it has been soaked in water for a specified period of time, also in grams (g)
For example,
if the weight of a dry brick is 2 kg (2000 g) and the weight of the same brick after soaking it in water for 24 hours is 2.2 kg (2200 g), the water absorption of the brick can be calculated as follows:
Water absorption = ((2200 g – 2000 g) / 2000 g) x 100
Water absorption = (200 g / 2000 g) x 100
Water absorption = 10%
Therefore, the water absorption of the brick is 10%.
Third-class bricks water absorption rate than first and second-class bricks, typically between 20% to 25%.
- First-class bricks: 7.5 N/mm² to 10 N/mm²
- Second-class bricks: 3.5 N/mm² to 7.5 N/mm²
- Third-class bricks: 2.5 N/mm² to 3.5 N/mm²