One of the significant advances in the construction industry is innovatively creating materials that maintain energy efficiency in buildings. Clay hollow bricks remain as one of the best choices in the market to fulfil this aspect. Due to their strength, thermal effectiveness, and environmental friendliness, these bricks have a significant use in the implementation of projects of both residential and commercial nature. This blog delves into the different types, advantages, manufacturing processes, and applications of clay hollow bricks, offering a detailed understanding of why they are a preferred building material.
What are Clay Hollow Bricks?
Clay hollow bricks refer to a group of construction materials that are made by shaping and firing clay at very high temperatures. This is a specialised category among the various types of bricks used in construction. Due to the hollow formation of these bricks, they have low weight but retain high strength, thus making them suitable for both load-bearing and non-load-bearing usages. The air in the bricks allows them to provide perfect thermal and noise insulation, and fire resistance, making them highly durable and environmentally friendly. Therefore, energy and cost efficiency can be achieved in buildings due to the immense decrease in the energy used for heating or cooling.
Manufacturing Process of Clay Hollow Bricks
1. Feeding of Clay: Clay is put into the box feeder, which, through conveyors, takes it to the roller crusher.
2. Crushing: A double cylinder roller crushes the clay to break it down into smaller, uniform pieces.
3. Mixing with Water: After the clay has been crushed, the clay is fed through a conveyor belt to a screw mixer, where water is added to the clay to make a homogeneous mixture.
4. Second Mixing: To get the right consistency, the clay mixture is sent through a second mixer just before the extruder is fed.
5. Extrusion: A vacuum extruder is used to put the clay mixture into perforated slabs, which are made by extrusion.
6. Wire Cutting: The extruded slab is wire-cut to form individual bricks.
7. Drying: The moulded bricks are dried in a drying shade. Drying takes 15-20 days during summer and 30 or more days in winter, depending on weather conditions.
8. Firing: The kiln is the place where the bricks are put once they are dried, and from there they are taken back after being fired to complete the manufacturing process.
Types of Clay Hollow Bricks
According the Indian Standards code IS 3952 (1988): Specifications for burnt clay hollow bricks for walls and partitions, clay hollow bricks can be of the following types:
- Type A: Bricks like these are both keyed and ribbed on the faces; thus, they have a rough texture and are more suitable for bonding with mortar or plaster in various brick masonry applications.
- Type B: These bricks are double-sided and have even smooth surfaces. They can be used in areas where no plastering or rendering is required, thus getting a nice and clean finish without any treatment of the surface.
- Type C: The bricks on one face are keyed for better adhesion, and the other face is smooth; thus, they give you a more adaptable option for different kinds of works, where the key side can be used for bonding and the smooth side for visible finishes.
Advantages and Disadvantages of Clay Hollow Bricks
Advantages
- Lightweight Construction: The hollow design helps to minimise the weight of the bricks, thus making them more user-friendly and easier to ship, which in turn leads to savings in the overall costs of construction.
- Thermal Insulation: The small spaces inside the bricks creates perfect insulation that keeps the surrounding temperature stable and at the same time saves on energy costs.
- Sound Insulation: The voids in the clay hollow bricks are designed in a way that they reduce the noise coming into the building, making the bricks very suitable for the construction of houses, business centers, and even factories where the requirement for soundproofing is crucial.
- Fire Resistance: The fire resistance property of clay hollow bricks is very high due to the natural properties of clay, making buildings equipped with them more secure.
- Strength and Durability: Hollow clay bricks enhance load-bearing capacity while reducing weight, ideal for load-bearing and non-load bearing walls. They are durable, with many historical buildings still showcasing their resilience.
- Ease of Installation: Because of their modular design and exact measurements, installation is made effective, following proven brick masonry techniques and basics, thus saving time and labour costs.
- Cost-Effectiveness: Lower weight reduces the costs of transportation and foundation. Moreover, their insulation properties result in the saving of energy throughout the heating and cooling cycles of the building.
- Aesthetic Appeal: Hollow clay bricks, which are made in different sizes, colours, and textures, give architects the opportunity to use them for creative design, thus building facades and interiors can be further enhanced by using them.
- Availability: They are widely available and locally produced, thus transportation costs are lower and regional economies are supported.
- Compatibility with Other Materials: It can be combined with steel, concrete, and glass without any problems, thus architects can come up with buildings that are not only structurally safe but also innovative.
- Environmental Impact: The product is made from natural, recyclable materials, and the energy consumption during the production process is low, which is in harmony with general sustainability goals.
- Recyclability: Hollow clay bricks can also be recycled for use after a building is demolished, thus the construction waste can be reduced and a circular economy can hence be supported.
Disadvantages
- Fragility: Though they are strong, due to their hollow nature, they are more prone to breakage during handling.
- Water Absorption: Substandard or improperly fired clay hollow bricks may take in water, thus causing structural problems.
- Higher Initial Cost: The process of making and transporting hollow bricks can be more costly than that of solid bricks.
Applications of Clay Hollow Bricks
1. Residential Buildings
Hollow bricks are one of the main materials used for insulation in various buildings, and as a result, homes made by using these bricks remain energy-efficient and comfortable throughout the year as they allow the flow of hot or cold air. Due to their quality of noise reduction, they allow peaceful living spaces.
2. Commercial Construction
In commercial buildings, hollow bricks have several factors that are most beneficial, making them a superior choice in the bricks vs hollow blocks comparison, such as being low weight and large sizes. The first property allows the building to be made in less time, and the latter one is advantageous in saving more money. Besides these properties, the bricks’ quality assures the building’s safety and stability.
3. Tall Buildings
Hollow bricks are perfect in tall buildings largely because of their lightweight property, discussed in detail above. Accordingly, the weight of the structure is reduced on the different supporting parts, which reduces the foundation costs of the building.
Maintenance of Clay Hollow Bricks
- Cleaning: Dirt, dust, and stains can be removed by using a soft brush or mild detergent. In case of a difficult stain, low-pressure washing can be used.
- Waterproofing: To prevent water absorption, especially for outdoor walls, the application of water-repellent sealants is recommended.
- Crack Inspection: Continuously inspect for cracks. Any damage should be fixed as soon as possible with the best quality mortar or filler so as to keep the structure intact.
- Brick Replacement: The replacement of damaged or broken bricks should be done as soon as possible to prevent the weakening of the wall.
- Sealing and Repainting: Along with aesthetic enhancement of the building, the resealing of mortar joints will contribute to the enhancement of the durability of the brick surface.
Conclusion
Hollow clay bricks provide strength, thermal insulation, and environmental friendliness, thus becoming the core of today’s eco-friendly buildings. Such bricks can be used not only in the construction of load-bearing walls of houses but also in the building of office walls, which results in both energy savings and structural benefits in the long run, thus the extra initial cost will be compensated. Any building can become more eco-friendly with the help of these bricks, and thus it is a big step towards the idea of sustainable cities, directly affecting the climate change issue in a positive way.
Apoorva H P Achar 
Hemali Patel