Civil Engineering - Building Construction - Discussion

Dubbing means filling holes in walls with mortar.

And what about blistering?

Blistering occurs when a fresh concrete surface is sealed airtight at a time when air voids are migrating to the surface. The air collects under the airtight surface and creates blisters. Several conditions may contribute to their formation. One is wind blowing over the concrete surface, reducing its moisture content. Another is a subgrade that is cooler than the concrete so that the top surface sets faster than the bottom.

A sticky mixture containing excessive fines also contributes to sealing of the surface and blistering. Lean mixes can add to the problem because they may have to be worked excessively to produce the desired finish and the extra work may seal the surface. Finishing too early and the misuse of tools also can lead to blistering.

Examples of such misuse are making an excessive number of passes with a vibrating screed, excessive use of the jitterbug, excessive use of the bull float or using a power float with the blade not flat.

What is meant by peeling?

What is meant by hacking?

It should be noted that any kind of plaster needs to be able to stay put on host surface. If not, it will just fall off. It is therefore a common practice to either roughen a surface for better cohesive power of the plaster, or layer a cohesive film. Where roughening the surface is required, methods like sandblasting or hacking are used.

Hacking is usually done with a hammer and chisel. Periodic and shallow indentations are made on the surface, this results in a rougher surface and will provide better cohesive potential for the plaster to stick to.

What is ply rough ground?

What is peeling?

Peeling means dropping of the top layer that may be painted layer.

Blockwork wall joining side/ plastering min 75-80 Hacking Impressions per sqft to be present and to be made with Hacking Machine only and the Impressions to be made in cross X shape only.