It is used to strengthen concrete because of its poor tensile strength. The presence of deformed bar is key to help concrete to adhere to a bar's surface. In most cases around South Africa, an engineer is commissioned early on to specify what mesh and bar are required for retaining walls, footings, slabs or suspended slabs.
South Africa, mesh is available in square and rectangular bar spacings. Square mesh has its naming convention coded by 2 numbers. The first number demonstrates the size of the bar and the second number demonstrates the spacing of the bar to create the mesh fabric.
The rectangular mesh is different than square mesh as the steel fabric spacings form rectangles rather than squares (as the name suggests). In addition to this, the bar cross wires are all the same size bar (7.6mm) no matter the size of the mesh sheet, but the long wires are different size bars depending on the mesh size. Rectangular steel mesh uses a three-number naming convention. The first number demonstrates the size of the bar long ways, the second number demonstrates the size the spacing of the bar one way and the third number demonstrates the size of the bar cross ways.