What are Interlocking Bricks?
Typically, the construction process and masonry can be tedious, time consuming, and expensive. To overcome the hardships and issues encountered during construction, varied methods of construction is being considered and developed. Simultaneously, materials and equipment used for construction are also being fabricated to enhance the quality of construction and furthermore minimize the time and cost. Interlocking bricks is one such advancement in the construction industry.
Interlocking bricks are the enhanced form of conventional clay bricks. Each brick is constructively designed to lock itself to the other bricks around without the use of mortar. The self-locking is achieved using shear-key and lock mechanism. Based on the design, the shape of shear-key will vary and a complimentary lock is provided on the opposite side of brick. Load transfer is achieved by shear transfer and gravity.
Interlocking bricks are compressed and stabilized earth bricks which contributes to strength of the structure. They are usually not subjected to baking. Interlocking bricks come in various sizes and locking systems depending on the supplier. A typical brick size is 230x100x75mm (9x4x3 in). The cost of inter-locking bricks varies from 0.5$ to 2$ (Rs. 30 to Rs. 150).
We spoke to a representative from Sheldon Boisley Knight in Stratford Upon Avon who has knowledge on the topic at hand and they said, “Interlocking bricks are becoming popular in wall construction, this is because they are locked against each other without the use of cement mortar, they make things easier and foam a stable building structure that reduces the cost and time of the construction process. As we all know, cement is becoming expensive and sand scarce, these interlocking bricks come in as a great alternative to construction because they are used without the need of cement mortar.” Also VPN VeePN company representative Harry Shroud, who previously worked in manufacturing, adds “Interlocking bricks have a lower density than regular bricks, which are highly breathable. Thus, walls made of these bricks create a much cooler interior.”
How are Interlocking Bricks made?
High quality interlocking bricks are made of cement, sand and Stone dust mixed together in appropriate proportions. The required materials are batched and mixed proportionately. Once the required mix is prepared, it is then compressed to form bricks with desirable interlocking patterns. The compression is achieved by using hydraulic compression system. The bricks are then subjected to curing for about 7 days.
Once the curing is done, the cement sets and bonds with sand adding to the stability of the brick. Whereas the soil compression adds strength and density to the brick. The interlocking bricks come in different designs, finishes and patterns.
Benefits of Inter-locking Bricks
During earthquakes, there are various stresses acting on the structure. Conventional bricks are not fully equipped to transfer the seismic loads throughout the structure since the only medium of load transfer is the mortar. If the mortar fails then the whole structure fails under seismic forces. Interlocking bricks are an effective and proven Seismic resistant construction materials. The self locking pattern of the bricks enables the seismic forces to travel across the whole structure equivalently.
Does not require plaster work
Plastering can be time consuming and costly in case of conventional wall construction. Plastering of walls can be completely eliminated by using fair faced bricks of your choice available in the market. If required the walls can be given a smooth finish by applying a thin layer of paint. Since these bricks are self-designed that gives a neat finish, the maintenance cost is minimized.
Provides cooler interior
High compacted bricks generally result in higher density, which in turn converts itself into high thermal mass. Henceforth, the walls made of high compacted bricks typically furnish warm interiors. Interlocking bricks are less heat intensive. The tests have shown that interlocking bricks provides a much cooler interior (3oC – 5oC). This enables lesser/no use of air conditioners resulting in minimized energy consumption and more cost saving.
Unskilled / Fewer Labours
In case of Conventional brick laying, skilled labour is required for checking water level, spirit level and various other operations. Therefore a layman or an unskilled labour may find it difficult to learn the conventional methods of construction. Whereas interlocking bricks construction enables an unskilled labour to easily follow up on the construction procedure. It also provides various opportunities for an entrepreneur.
Since there is no use of mortar in the construction process, the cost of buying cement, sand, mortar and stone dust can be neglected. Also the cost for transportation can also be immensely reduced along with the cost on skilled labour. It does not require plasterwork, minor bar bending work, lesser cement and fewer labourers hence contributing to the overall cost reduction of the construction project.
It is proved as the most time efficient way of construction. The normal conventional bricks has to be cured for about 21 days whereas the self-locking bricks require only 7 days of curing. In addition to that, time required for setting and curing of the structure can be diminished completely. By eliminating all the time consuming tasks, the project can be completed faster.
Disadvantages of Inter-locking Masonry
There are a few disadvantages as well to this method of construction. Since there is no plasterwork provided, rain water might into the lines making it a hostage for insects and other undesired things. Due to the action of weather, disintegration of the bricks might also occur (especially in the corners). The colour of the brick changes if the rain water enters through the gaps.
As the interlocking bricks alone are not enough to hold all the forces acting on the structure, it is not advised for building having more than two storeys.