UGANDA, Kampala | Real Muloodi News | Bricks, bricks, bricks that is the question. Which type of brick is best for construction? Is it burnt clay bricks, or solid or hollow concrete blocks? Well, it depends on the intended use, and its quality. Joseph Oryang, an engineer, explains that the type of bricks or blocks used in construction depends on its structural design of the project and the designed load it will bear.
Let’s explore the physical makeup of each type of brick, and which is best to use in a project.
Burnt bricks are formed in molds. Brick makers lay them out to dry for some time, then burn them at an elevated temperature to harden them and make them more durable. The baking process gives the bricks mechanical strength and improves resistance to moisture.
Advantages of Burnt Bricks
Best For the Foundation
Burnt bricks are the best for laying the foundation. Joseph Oryang explains that burnt clay bricks can withstand any chemical corrosion or water effect compared to cement or concrete blocks. They are more flexible, and the cracks do not go through them quickly.
According to Aloysius Mutuku, a contractor with Concept MacFaj, you may face structural issues with blocks for a foundation if they are not of high quality. “If one uses substandard blocks, and the area gets waterlogged, they will disintegrate whereas bricks will not. Even waterlogged bricks will eventually dry up and return to their shape and function. Hence an uncompromised foundation,” he says.
Mutuku explains that to avoid inconsistencies in quality between block manufacturers, some people opt for burnt bricks. After being baked, bricks need no further treatment. Blocks, however, need to be ‘cured’ by watering them. Watering allows the mix to harden well and avoid disintegration because of dryness.
Mutuku says not all blocks are well cured. After a while, they cannot carry the weight they intended to take.
Lawrence Simiyu, a construction contractor, says some block makers use rough sand and cement instead of stone dust. As a result, they produce an inferior product. Furthermore, such blocks will not hold together as intended, and they will disintegrate. However, baked bricks will not deteriorate unless mishandled.
Concrete blocks are a mixture of stone dust or sand, gravel, cement and water moulded to create a solid rectangular block. The concrete blocks come in either solid or hollow blocks.
Advantages of Concrete Blocks
Blocks get the work done faster because they cover a more extensive area. One will therefore need fewer blocks compared to bricks, which translates into lower labour costs.
Unlike small clay bricks, Oryang says hollow cement or concrete blocks are better because not only do they give you room to save on construction costs, they lessen the weight or load of the entire building. Well-laid blocks save money. Blocks done right gives contractors a choice whether or not to plaster and paint, thereby saving even mroe money.
The blocks that interlock can build walls, water and septic tanks without using mortar between each block. Interlocking blocks saves up to 40 to 50 per cent of the building costs.
Nassolo Racheal the Business Development Manager of East Africa Roofing System Ltd. says high-quality concrete block is the most durable material. A house built with well manufactured concrete blocks forms a more robust wall that can last for over 100 years.
Oryang also agrees with Nassolo, “If you get outstanding quality concrete blocks from a credible manufacturer, they are normally stronger and the load they can carry is greater than that of locally baked clay bricks. For a load-bearing structure, look for the best made from pure clay but not from pure ordinary red soil. Those made from red soil are not strong and will not carry much of a load,” Oryang says.
Unlike clay bricks, concrete blocks from factories are uniform. When you get one side smooth, the other automatically becomes smooth as well.
“If you do not plaster locally made clay bricks, the wall will not appear smooth. You will also have to make the plaster thicker,” Oryang says.
Disadvantages of Concrete Blocks
Haruna Katerega, a builder, says, the challenge with concrete blocks is that they are expensive. To minimise the costs, some builders have resorted to making substandard blocks on site.
According to Nassolo, blocks made from the site do not have the same comprehensive strength as those that are factory-made.
Blocks are Heavy
According to Mutuku, since blocks are heavy, they are cumbersome to carry around. Thus, masons typically ask for a slightly higher wage than when laying burnt bricks, which may off-set some of the savings gained from the job getting done faster.
Eng. Dr Moses Kiiza Musaazi, senior lecturer at Makerere University and Managing Director Technology for Tomorrow Ltd, says concrete blocks are unsustainable. The compressive strength of sand blocks is low and cannot withstand pressure. He says if you drop a concrete block, it completely disintegrates.
Eng. Musaazi says stabilised soil blocks are an incredible breakthrough in achieving affordable house construction in Uganda. One bag of cement can make up to 130 -150 stabilised soil blocks compared to 25 concrete blocks.
Mr Oryang says that when you calculate the total cost of concrete blocks, you may find that they are almost the same as someone who opted for burnt bricks. Burnt bricks are considerably cheaper, with a piece costing between USh300 to USh500, or more. This is in comparison to concrete blocks that cost between USh 2,000 to USh2,500 each. However, with clay bricks, you have to be ready to spend a lot more on cement, sand, and labour.
What is most important, however, is the quality of the brick or block. Cheaper, inferior products will usually cost you a lot more in the long run.
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