A brick is a brick is a brick, one would think. Wrong. Wait until you try using them and find either that they crumble or else are too exorbitantly priced and throw your construction budget out the window.
Cement bricks are a great option, especially for the foundation and load-bearing walls of buildings. They are durable, water-resistant and regarded as environmentally friendly. They are also cost-effective, so much so that they are often used for low-cost housing. They become stronger over time and also provide good sound insulation. And they provide lots of options for finishes as you can plaster and or paint over them.
There are hollow and solid cement bricks of different sizes. The hollow ones are lighter and have the advantage that if you use them to construct a wall, you can drive bars through the wall to reinforce it and make it even stronger. If you are concerned about their strength, they can always be filled with extra cement mortar.
So does this mean that any cement brick will do? A lot depends on what they are made of.
A cement brick is technically known as a concrete masonry unit (CMU). The reason cement blocks differ in quality is because they are made of a combination of sand, aggregate, water and cement – and each of these elements can vary in type, which will then change the overall product.
There is not just one aggregate, for example:
Some of the aggregates of cement bricks are:
- industrial waste;
- crushed stones;
- a mix of sand and gravel;
- fly ash, which is the fine powder formed from the burning of powdered coal;
- limestone; and crushed dust or grit mixed with sand.
Sand can vary enormously so if you are making your own bricks, make sure you use an appropriate type. Using sea sand will results in a weak brick. Building sand is ideal and mixes well with cement, and you can also add gravel to it. You could opt for stone instead of sand but it would need to be refined/graded and this will push up the cost.
And of course you need quality cement. It is always best to choose cement which carries the certified mark that shows it has been approved by the South African Bureau of Standards (SABS). That way you know you are getting high-grade cement that is strong and has long term durability.
For expert advice on the correct cement products to use to achieve the best possible results contact the Sephaku call centre on 0861 32 42 52 or speak to your technical representative.