Concept behind soaking of bricks in water

We usually come across masons soaking bricks in water prior to laying. The reason stated is that strength of construction will improve. This is a myth.

The fact is that presence of lime in cement causes it to generate heat while setting. Moisture content in cement slurry comes in contact with this heat wave and consequently gets dried up, resulting in cracking of slurry. The moisture in turn would get absorbed by dry bricks which would make the building vulnerable. Wetted bricks are not exposed to the moisture emitted by slurry and are helpful in keeping the temperature of cement within control for the initial day. For a continuous span of 7 days from next day onwards, regular water spraying is recommended to keep the cement temperature within control.

Steel or mud centring for roof?

Steel has definite advantage over mud. Air gaps in concrete evenly laid on steel reinforcement have to be eliminated for preventing contact of iron beams with humid air that can induce rusting gradually. Such beams break easily and render the structure vulnerable. Steel centring allows for even covering of beams as a vibrator is used for removing all gaps in concrete that can potentially trap air. Such concrete roofing would be exceptionally strong as particles would stick together firmly and water absorption won’t happen during curing.

Shattering the myth: Concrete drinks water to become strong

A common myth exist that concrete drinks water during curing process and becomes strong. The fact is that concrete setting occurs with generation of heat. This heat would dry up water content in slurry and would induce premature cracking of slab. Concrete usually takes three weeks to settle down decisively and hence during this period, it is kept under water layer for making the cement temperature remain within control.

The availability of quick setting cement has brought down the curing period considerably.

Surkhi does not waterproof the roof

Surkhi offers an insulation cover to the roof which prevents heat from radiating into the rooms. Clay tiles can also be alternatively used.

Waterproofing can be easily done by mixing a suitable chemical with concrete before the setting process. Water ingress in roof would be conclusively prevented. The chemical gets crystallized and ionized upon coming in contact with water and prevents leakage.