Saturday, May 21, 2011


MANY MYTHS exist about the construction materials and the process of construction. We would want to dispel a few in these columns.

Here are some random Gyan about some of the important aspects of construction of a house. We have elaborated a few important dos and don'ts for your reference.
Soak the bricks in the water before laying it in masonry. This will not improve the strength of the bricks but help the cement mortar to cure well.
Cement is made of lime. When cement sets, heat is generated. This will evaporate the water content and the cement slurry will dry up and crack. Dry bricks will make it worse by absorbing the wetness of the cement slurry. Wet bricks will avoid water absorption and also keep the cement mix cool for the first day. From the second day, the wall must be sprayed with water to cool the cement at least for seven days. 

Better alternative:-
Steel centring for the roof is a better alternative than mud centring. When concrete is spread on the steel reinforcement, the concrete must be packed well without air gaps in the concrete. With air gaps, the iron rods are exposed to weather and may rust over a period of time. The rusted rods break and the slab may crack. With steel centring, concrete can be vibrated with a vibrator, which will remove air gaps and cover the steel rods evenly. A compactly packed concrete will adhere very well and the strength of concrete roof will also be good. Concrete will not drink water when it is cured.
A mason at a construction site of my friend was refusing to use waterproofing chemical in the cement concrete for the terrace slab of the house. I asked him why he was against it. He said that by using the solution, the concrete would not drink water when it is cured and the cement concrete will not be strong. Such myths are common in building industry.
The truth is, setting of concrete is a heat generating process (exothermic reaction). When the curing water is stagnated on the concrete surface, the concrete is kept cool. The setting time of concrete (with 43 grade cement) is 21 days and therefore for three weeks, the concrete is kept under a sheet of water.
Nowadays, quick setting cements are available whose setting time is faster for quicker construction. The curing process can be reduced depending on the recommendation of the manufacturer.

Surkhi is not water proofing material as many think. Surkhi is a weatherproof layer or heat resistant layer, which insulates the roof from getting heated. Heated roof will radiate the heat into the rooms. Clay tile is also a good heat insulating material for the roof.

Easy application:-
For waterproofing, a variety of chemicals are available in the market, which can be mixed with the concrete and applied on concrete slab. This will stop the water from entering the roof. These chemicals, through different processes like crystallisation and ionisation, protect the roof. A leaky roof is not only a botheration, the wetness will also harm the iron in the concrete and render it weak. 

No comments:

Post a Comment