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.