Wednesday, September 26, 2007

The bare essentials

Doors could be pivoted with only the top and bottom rails fixed. As for doors in the terrace, they could be of steel instead of wood.

A house designed by Charles Correa.

OFTEN CHOICE leads to confusion. This is especially true for a house builder who has a bewildering range of options to choose from. This week, let us take a look at the bare essentials a builder should know before he embarks on a construction activity so that he can choose what best suits his work.
The most primary and important part of any house is its structure. It consumes about 7 to 15 per cent of the total building cost. The foundation is an integral part of the structure and the first stage of construction. The type of foundation is determined by the soil.
In Chennai, mostly, there are two prevalent soil types — the sandy soil and the clayey soil. The foundation cost also varies accordingly.
In the case of sandy soil, the foundation will primarily be of brick wall or random rubble foundations or isolated R.C. Column footing with plinth beam and hence is quite cheaper than the other types. But for clayey soil (which you could find out by looking at a nearby construction or asking the local mason), the foundation is a little complicated and costlier as you have to go in for a pile or raft foundation. Also, a soil test becomes essential. The test could be done by testing agencies and would cost you about Rs. 7,000 to 10,000 per pit, depending upon the depth for which the soil is taken. But for a house where lakhs of rupees are going to be invested, this nominal charge should not be a deterrent.
Having got the soil reports, a structural consultant can be engaged in consultation with the architect, who could `design' the R.C.C. foundation, lintels, roof slabs, sumps and overhead tanks at a nominal cost, taking care of factors like earthquake, future construction, and who could also do periodical checking as to whether the work is being executed properly with good steel and concrete.
Structures designed improperly are always dangerous and even the sumps and overhead tanks have to be carefully designed. If not, the sump may crack resulting in water wastage and even sewage leaking from street lines could get mixed with water.
Other than for safety reasons, a structural consultant could be employed to design roof slabs effectively and economically. He could bring down steel usage to 2.5 kg/sqft from the conventional 3.5 to 4 kg/sqft.
The other bare essential is the walls, but we have already seen a lot about it. Let us see how the doors and windows can be designed. Available options are in the form of teak, sal from Kerala, Padauk country wood and rubber wood. Teak can be used sparingly for main doors only as it is expensive. Even with wood, windows and doors can be designed economically. Windows can be designed without frames by pivoting the shutter directly into the walls. This technique has been followed by the British architect, Laurie Baker, in many of his houses in Kerala. Also, doors could be pivoted with only the top and bottom rails fixed.
As for some special doors, like the terrace doors, they need not be in wood; they could be of steel instead. Hollow steel sections and steel sheeting covering makes these doors weather-proof and provides for excellent safety. They are economical and may cost Rs. 2,500 a door. Grilles could be 10 or 12-mm square rods, fixed by M.S. flats, and supports are taken in directly into the wooden frame to prevent conventional screw type grilles from being removed.
The next essential would be the plumbing and sanitation work. These take up about 7 to 10 per cent of the total construction cost and hence are very important. Most often, toilet floors start leaking, making the ceiling below damp, and in some cases, even dripping. Proper water-proofing along with a `pressure test' should result in a good damp-proofing for toilets. The `pressure test' could be done by retaining water in the sunken portion of the toilet and studying with a pressure gauge. If there is leakage, you will have to do `pressure grouting' in the leaking area. This has to be done before filling up the sunken portion and the tiling work.
Sun-shades and balconies are subjected to stagnant water. Good water-proofing is necessary there as well. The spout can be a good rectangular aluminium trough (2" x 2"), which could prevent water-clogging. Similarly, on terraces, flashing of tiles along the parapet is necessary to prevent water from seeping into the main walls. Left unattended, this may lead to short-circuiting of electrical lines.
Plumbing lines need not be concealed, but proper architectural and structural detailing could be done to facilitate easy maintenance.
These ducts could be used to set up distribution boards at every floor with a simple electrical circuitry, with enough space in some PVC conduits for further electrical requirements such as the modem, TV cables and LAN. For high-rise flats, the core also has to accommodate the earthing line for lightning arrestors. The electrical work would cost 7 to 10 per cent, excluding the fixtures. Employing an electrical consultant should be considered as well.

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