Most of our concrete surfaces are smooth in nature. These smooth surfaces are not suitable for further masonry works – Block work & Plastering.
We need to prepare these surfaces such a way that the bonding between concrete and upcoming mortar is optimum. The same can be achieved by Hacking process or by Chemical treatments. In this article let’s discuss about the Hacking process.
Hacking is the process of making concrete surface rough by creating controlled indents on the surface. The same can be achieved manually using Hacking Hammers or by mechanically using Angle Grinding Machines.
Using Hacking Hammer:
By using hacking hammer we can achieve indent size of 25mm in length, 3mm & 3mm in width and depth respectively. we need to make 70 to 80 indents per sqft to achieve optimum bonding.
Using Angle Grinding Machine:
By using Angle Grinding Machine we can achieve indent size of 50mm in length, 4mm & 4mm in width and depth respectively. We need to make 50 to 60 indents per sqft to achieve optimum bonding.
The Hacking can be done in various patterns. The Cross stitch / Fish bone pattern as shown in the above picture will be most effective one.
Further to Hacking, a coat of cement slurry will be applied and cured for three days before starting Block work. This process further enhances the bonding between existing concrete surface and upcoming mortar.