In Pakistan, house construction methods are not always as advanced as in other developing or developed countries where the latest engineering technologies are already being adopted. In most parts of our country, the most commonly used method for house construction is known as brick structure. In this method, load-bearing clay bricks are used to complete the structure and the load of the whole structure rests entirely on the bricks. In some parts where the terrain is not plain or the soil is not hard enough, the frame structure method is adopted instead, where the load of the structure is carried by the raft foundation, columns and beams — however, even in this method, bricks are used as partition material for walls. There is another material that can be used instead of bricks for partition walls, called blocks. Blocks come in different types, such as:
- Concrete solid blocks
- Concrete hollow blocks
- AAC blocks
- CLC blocks
Concrete solid blocks are very commonly available at economical prices in local markets and can also be made on site using moulds. The raw material used for this kind of block consists of cement, sand and fine crush. These blocks can cost around Rs 25-30/block if made on site, and the most common size of this block is 8″x8″x12″. If these blocks are not made on site, an additional cost of Rs 15/block applies, which includes loading, offloading and carriage.
AAC stands for autoclaved aerated concrete blocks. These blocks are made using cement, lime, fly ash, gypsum and an aeration compound with high energy input. They can be manufactured in advanced, well-established plants equipped with steam boilers and high-pressure autoclaves. Currently there is no company in Pakistan actively producing AAC blocks, however a few companies that started operations but could not continue due to low demand for this type of block back in 2018-2019 were selling them in the price range of Rs 200-300/block, in the following sizes (LxHxW):
- 24″x8″x9″
- 24″x8″x6″
CLC stands for cellular lightweight concrete blocks. These blocks are made using cement, fly ash, water and foaming agents. They don't require a well-equipped plant — a simple foam generator and ribbon mixer is enough to manufacture this block. CLC blocks in Pakistan are currently being manufactured by Banu Mukhtar, in the following sizes, in the price range of Rs 175-200/block:
- 24″x8″x8″
- 24″x8″x6″
- 24″x8″x4″
CLC blocks can be used as partition blocks if you are building your house using the frame structure method. Since this block is very lightweight, steel cost can be saved by designing a smart structure and not using a huge amount of steel in the building. Secondly, it also provides heat and sound insulation. It doesn't require curing like clay bricks before fixing. Wastage is very low since all blocks are made on plants — there is no A grade or B grade block, each block is of the same quality, unlike clay bricks which have 5-7% wastage in the form of low-quality bricks in each stack. Both sides of the wall have a fair-face surface in the case of CLC block work, unlike clay bricks where one side is rough and the other is neat — hence reducing overall plaster and mortar cost. Very little mortar, up to almost 5mm, is required in the case of CLC blocks for horizontal and vertical joints, unlike clay bricks where mortar can go up to 10mm during fixing.
Team Overc's has made a brief video about the introduction, advantages and method of installation for concrete blocks: