South Africa employs the traditional method of building houses. We use bricks for the main structure. The two main kinds of bricks used in construction are either cement or clay stock.
Most buyers make the decision on which brick to use based on price only. Cement stock bricks may be cheaper, but there are other factors you need to consider. Namely manufacturing, strength and thermal efficiency.
Cement stock bricks consist of sand aggregates mixed with Portland cement. They cure over some time and are more consistent in size.
Clay stock bricks consist of natural clay which cures in a fired kiln.
Although both bricks are approximately the same size, each has different benefits.
Bricks have various compressive strengths ranging from 7MPa through to 50MPa.
The manufacturing process of cement stock bricks allows for more control in the variation of brick strength. Yet, with clay stock bricks, the majority delivered to a site will be stronger than needed. This is to compensate for the variation in strengths produced during manufacturing.
South Africa’s climate ranges in daily temperatures of 20 to 30 degrees Celsius. It is important to know how each brick reacts to temperature changes.
A clay stock brick expands and contracts much less than a cement stock brick. This means that there will be fewer cracks in your plaster. Clay stock bricks are a little more brittle though. So you can expect more settlement cracks with foundation or subsurface movement.
On the plus side, a clay stock brick has a higher thermal efficiency value compared to a cement stock brick. Making it a better choice for an energy-efficient home.
We recommend clay stock bricks for most residential projects. Low-cost housing or projects that don’t need energy-efficiency can consider using cement stock bricks.
Be sure to look at these factors when venturing into a project. If in doubt, consult your project engineer who will be able to confirm what type of brick to use.
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