COMMON MYTHS

Concrete bricks are not as strong as clay bricks…MYTH

All the structural elements of a building, from the foundations to the lintels and slab, are made of concrete. The bricks are even glued together with concrete. So why would you consider concrete to be in any way unsuitable or not strong enough for the masonry? Both clay and concrete bricks are made to a strength specification. A 14MPa (compressive strength) concrete brick is exactly the same strength as a 14MPa clay brick. One is not stronger than the other. There is a comprehensive range of strength
specifications from 3.5MPa up to 21MPa engineering grade bricks available.

Concrete bricks cause cracking…MYTH

Poor quality masonry and workmanship, the incorrect specification and application of Brickforce, as well as inadequate mortar mixes (i.e. leaving out builders lime), are the most common reasons for cracking in walls and are largely responsible for the existence of this myth. Normal settlement of the structure, including the foundations, can cause settlement cracks. These factors would apply to all forms of masonry, including both clay and concrete, which are subject to the same stresses.

Concrete bricks allow moisture penetration… MYTH

Water penetration of a wall occurs through fine cracks at the interface between the masonry unit and the mortar joint, and only very rarely through the masonry unit itself. The greater the bond between the mortar and masonry, the greater the resistance to leakage. Large scale tests have shown that lime mortar has a 60% higher bonding strength than non-lime mortar provided that jointing of the wall has been done. Cape Brick masonry units have very low (4%) moisture absorption properties.

Buildings built with concrete bricks are cold… MYTH

This is a wide spread perception caused by the fact that concrete masonry is gray (perceived to be cold) and clay masonry products are red (perceived to be warm).
The truth could not be further misrepresented. Due to its density, concrete masonry has excellent thermal insulation properties. The thermal mass of concrete slows down the passage of heat moving through a wall and allows the masonry structure to absorb the heat, keeping the inside cool during the warm day cycle and then allowing the heat to gradually transfer through to the inside during the cool night cycle, keeping the building warm during the night.

Concrete bricks are only for low cost housing…MYTH

Concrete masonry was started on the back of large low cost housing developments in South Africa. Combined with the fact that concrete masonry is more cost effective (cheaper) than clay masonry, a myth was created that “cheap” concrete masonry was only used for low cost housing whereas more expensive clay masonry was regarded as superior. Over time the truth and perceptual change is that concrete masonry is now the preferred choice for structural load bearing buildings around the world, providing
a more cost effective and durable building system. Some of the most expensive and luxurious private residences in South Africa and the world are built from concrete masonry.