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Design
&
Roofs
Uday Sunder Shrestha
The Design
The first step to build your dream house (or any
construction works for that matter) starts with the
selection of a good designer. And a good designer is
one who understands your dreams and interprets it
onto practical designs on paper before the actual
construction begins. Selecting a good designer can
of course be difficult and are subject to your
level of awareness in this field, access to
designers and of course the value you are able to
give to them. Designs are not objects that one picks
off the shelf. While each design is unique (since
they are site specific and caters to ones individual
needs and lifestyle), good designs are the product
of functional space planning and a choice of
appropriate building materials, that not only
addresses the owners financial constraints but
aesthetically as well as structurally lasts its
intended lifetime.
The Construction
While constructing a house, the owner seldom gets
involved during its structural part, although it
generally constitutes about sixty percent of the
total construction cost depending on the
construction type and space planning. However, since
it is the backbone of a building, due importance
must be given to it, especially since we lie in a
seismically active region. It is also important that
these designs be interpreted well and strictly
followed up with proper supervision during the
construction phase. One must also understand here
that it is possible to make the building earthquake
resistant at a relatively minor increase of about 5
to 7% in its structural cost. Hence ask your
designer for the proper detailing as required in
such cases.
So much so for the structure, where the owner
generally has little or no say towards its type and
is usually dependant on the designer. However, as
the finishing part approaches and the building
begins to take shape, it is now time to review the
construction estimate provided by the designer. This
is because adjustments may need to be made on the
pre-defined finishing quality and schedule with
respect to the total budget you had allocated, and
you do not want to be left with your house half
finished. Once you are confident as to what your
limit is, you can now go hunting for the best that
the market has to offer regarding finishing
materials. However, a little homework and research
will save time as well as ensure that you have
purchased what you wanted.
Starting from this issue on ‘Ceilings and Roofs’, we
shall try to guide you in a series of articles, on
possible designs and the wide range of finishing
materials available in the local market for floors,
walls, ceilings, door/window openings and sanitary
and electrical fixtures. We shall also be talking
about the materials merits, demerits, areas most
suitable for its application, methods of application
and of course its cost.
Ceilings and Roofs
Depending upon the design, ceilings and roofs can
either be sloped, flat, or even curved - the flat
roofs of course being the cheapest and easiest to
construct. However, each type has its own advantages
and disadvantages. The type adopted not only needs
to address its structural stability but also its
long term effect on maintenance as well as the
affect on the living space it covers.
Have you ever noticed that your top floor is usually
hotter than your lower floors – especially when that
floor is of reinforced cement concrete (RCC) – and
more so after the sun sets? And if your roof has a
metal sheet covering, the room is unbearably hot
during daytime, but is much cooler after the sun
sets? In the case of RCC - the most common type of
construction used – it has an inherent property to
slowly absorb heat and retain it for a long period.
Hence the roof, which takes the full blast of the
sun during daytime, absorbs this heat and as it gets
cooler, starts to radiate it out to the space below.
So what is the solution?
Naturally the answer would logically be to prevent
or minimize the effect of the sun on the roof or
prevent the absorbed heat to be transferred to the
space below. Very true, and this can be accomplished
in many ways. One method of minimizing the absorbed
heat could be to lay another material over the RCC
slab which has lesser heat absorbing properties
(insulation) like baked clay roof tiles. Clay has
excellent insulating properties and hence can be
very effective in such cases. However although
glazed tiles are available, defects during
installation and damage to the glazing during use
could promote water seepage instead, as these tiles
are porous. Hence proper water proofing of the
under-floor is advisable before its installation,
especially for flat roofs. Another problem with clay
is its affinity towards water. Moss and algae can
grow on tiles which remain wet and damp for a long
time, turning the original colour of the tile into a
ugly green and making the floor slippery.
Fortunately this can be removed by simply scrubbing,
using a standard scrub brush. Avoid using a chlorine
bleach as it can remove the glazing as well as the
colour of the tile.
Heat transfer from roofs with metal coverings are
easier prevented from below the covering. You could
opt for a false ceiling of either gypsum board or
plywood. To increase the insulation property,
insulating materials like Styrofoam is available
which can simply be fixed from below the metal
covering or laid over the false ceiling. It is
waterproof, lightweight and efficient in preventing
the transfer of heat. Styrofoam can also be laid
over walls or the RCC floor and then covered with
the desired finishing material. However, it has a
disadvantage of being highly inflammable. Another
solution in these types of roof coverings would be
to install exhaust fans to pump out the hot air. Hot
air rises up and hence the location of the exhaust
needs to be near to the ceiling. In addition, a
fresh air supply source, preferably at the other
lower end, is needed for proper ventilation
throughout the room. Exhaust fans can be either
electrical or wind powered. The wind powered
exhausts, called air vent turbine, have vertical
vanes which are powered by the wind and are fixed on
the ridge of the roof over the metal sheet covering.
Barring the initial cost, it requires negligible
maintenance and running cost, and are locally
available. As with all exhaust fans, its efficiency
can be increased with a fresh air supply.
It is easy to fall into a false of security by
simply copying or taking unprofessional and
unethical advice. Do not copy without reason or
applying logic. If you have to copy, copy those
which are time tested. Architecture is something
which develops with time and experience. Just be
aware that you are not the guinea pig in the
process.
CLAY
ROOF TILES:
-
Kantipur Marble / Bath N Room,
Ph: 4352722 / 4255041
Riddhi Siddhi Marbles (Daksh Prajapat),
Ph: 216055
Shree Dakshin Barahi Brick Factory,
Ph: 4780969, email:
dakshin@wlink.com.np
-
AIR
VENT TURBINE:
Lazimpat Metal Engineering Works,
Ph: 4428506, email:
lazimpatmetal@gmail.com
-
STYROFOAM:
Atc Pvt. Ltd., Ph: 4261220 / 4262220,
email:
atc@wlink.com.np
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WATER PROOFING
Pest Control Nepal, Ph: 4492285,
email:
sks3p@wlink.com.np
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