The wire mesh consisting of galvanized wire of diameter 0.5 to 1.5mm spaced at 6 to 20 mm centre-to-centre is formed by welding, twisting and weaving. Specific mesh types include woven or interlocking mesh, woven cloth, and welded mesh. The welded wire mesh may have either hexagonal or square openings. Meshes with hexagonal opening are sometimes referred to as chicken wire meshes. The hexagonal wire mesh is cheaper but structurally less efficient than the mesh with square opening because the wires are not oriented in principal stress directions. 
Moreover, the rectangular meshes have better rigidity when placed or tied over the skeleton frame, and do not sag during placing the mortar. Meshes with square openings are available either in the form of welded wire mesh or in the woven form. The welded wire meshes have a higher young’s modulus and hence provider a higher stiffness and less cracking in the early stages of loading.