The endeavour in designing of buildings should be to study thoroughly the climatic conditions and provide suitable protection. This should be so handled that it produces a perfect and aesthetic form. Properly combined with the functional and efficient internal planning, this will result in a building satisfying to human needs.

INTRODUCTION
Design of buildings mainly depends upon:

(i) Requirements and purpose,
(ii) Building materials and method of construction, and
(iii) Climatic conditions.

There are other factors too, but the above predominate. These are also inter­ related and are to be properly coordinated in a successful design. However, in this paper it is intended to study the effect of climate on architectural expression of buildings.

As we know, the climatic conditions have almost remained the same throughout the ages, but the expression in architecture have varied due to various factors. These are mainly the building materials used, the method of construction adopted, and the economic and social conditions of the day. Considerable changes have taken place owing to the present-day technological developments, and hence the same old climatic conditions are being dealt with in the present-day, by different means and in different manner.

Just as different buildings can be distinguished by their expression of purpose, like a school, office or a residence, the external appearance and the planning should also express the climate for which it is built. The effect of climate will determine the general planning and also the external treatment. Though all the sides of a building should have harmonious facade, the different faces may need a particular treatment according to its orientation.

Natural light and fresh air is desirable in buildings. In temperate climates where air-conditioning is not needed, free flow of natural air is sought for. The size and shape of windows will depend upon the amount of light and air desired to be admitted.

From time immemorial, different ways and means have been adopted to provide protection against sun. Awnings which form typical features of our tropical bazars, projected roof overhangings which provide deep shadows, and well projected cornices and chhajjas have been freely used. Tropical countries in other parts of the world have similar methods. Such methods to suit the present-day conditions can be well adopted

CLIMATIC REGIONS
Different climatic regions of India will have its own type of building. to suit the climatic and other conditions. The main regions are Delhi and Northern India Region, Central India Region, Bombay and Western Region, Madras and Southern Region, Calcutta and Eastern Region. Assam Region and other Hill Regions.

NORTHERN REGION
The extreme climate of Northern India creates opposing problems and requires cooling arrangement for summer, while the sun is needed during the winter months. During summer months the south and west are to be well protected against the sun. During the winter months it becomes necessary that the sun should enter the building. Horizontal canopies of proper depth are sufficient for the south, as it will prevent the summer sun which is at a higher inclination during: the middle of the day, while it will also admit sun during the winter months, when the sun is at a low inclination. The west side is rather difficult to control. as the low sun will penetrate deep in the afternoon. The sun sets in the north-west. but being at a very low inclination at that time, is not very hot. For this purpose inclined vertical louvers are advocated. However, for some reason, if it is not desired to obstruct the view, then closely spaced straight vertical louvers will also serve the purpose. Combination of vertical and horizontal louvers, either inclined or straight, if used with discretion, will give satisfactory results.

The north side does not need much protection except a hood, for preventing glare and rain. The morning sun of the east is not very uncomfortable. but where desired. vertical louvers may be provided in the same way as on west side.It becomes necessary to prevent hot air of the summer months and also the cool winds in the winter months. Through draught is not very necessary except for the couple of months during the humid rainy season.

Normally there is little breeze in this region and if the breeze is available during the summer months, it is welcome. Rain which is less in this area is not much of a problem.South verandahs are desired, for residential buildings in this region, as they give good protection during summer, while during winter they provide useful sitting-out place. Open spaces for sleeping and sitting-out purposes are also necessary.

The main rooms when surrounded by other minor rooms, will keep the building cool, and protect them from the hot outside air. Underground basements also remain cool.Such considerations create a certain type of expression in the design of buildings and become characteristic of a particular region.

WESTERN REGION
The main consideration for the Bombay Region is the westerly breeze which is very desirable. The climate is humid and through ventilation is necessary. The temperature outside is not very high as in Northern India. However, some protection from sun is desirable. This should not again obstruct the breeze from west side. The beating of the monsoon from the west also needs good protection and requires deep and low hood. The west can be protected from sun by inclined vertical louvers, but this may obstruct the breeze and also the view. Movable louvers are preferable but they are expensive to provide and maintain.

SOUTHERN REGION
The hot and humid climate of Madras Region requires through ventilation and large openings for free circulation of air. The breeze is from south and south-east side. The east and west side may be provided with vertical louvers while the south an the north may have horizontal canopies. Protection from the beating of the rain is also needed on the south and south-east side.

EASTERN REGION
For the humid region of Calcutta, advantage should be taken of the south breeze. The vertical inclination of sun at noon is slightly on the north during the summer, and as it is practically over-head, horizontal protection on the north and south side will be sufficient for this purpose. The west can be dealt with as in the other regions.

Accurate studies of the inclination of sun during different seasons and for the various parts of the country can be easily made from the orientation charts published by the National Building Organisation. These also give other meteorological data.

SUN BREAKERS
Various types of methods have been used for protecting the buildings from sun. Louvers or sun breakers are used in variety of types and pattern to meet the individual need and to suit the orientation. These are of different types: vertical type, horizontal type, and combination of both vertical and horizontal, grid or chequered type. These can be fixed or adjustable. The louvers or canopies can be solid or partially louvered and can be straight or tilted. Different materials could also be used for this purpose. The louvers should be ingeniously used to provide adequate protection and at the same time it has to be seen that the pattern or form created by them is aesthetically satisfactory. They should also not collect dust or hide the view or stop the incoming breeze.

The louvers may be of concrete. These if thin, will not radiate much heat and will cool off quickly. Other lighter materials like foam concrete, asbestos cement sheets or aluminium sheets are preferable. Adjustable louvers are more effective and convenient, as they can be opened or adjusted to suitable angles for changing conditions. However, they are expensive and difficult to maintain.

Aluminium sheet tension louvers, which could be used for wider spans, are being manufactured these days, and are very useful and convenient. These can be used vertically or horizontally.

There is much scope in providing interesting compositions with the use of louvers. For example, at the Baroda House Annexe, New Delhi, the two wings of the building meet at an angle and face different orientations. Vertical louvers have been provided for one wing, while the other wing has horizontal louvers. This makes an unusual and interesting composition and at the same time serves the orientation to which the wings are facing.

BUILDING MATERIALS AND COLOUR
Climate also plays its part in determining the selection of building materials, which should be local as far as possible. Suitable colour and texture has to be provided. Light colours will reflect the heat away, while glare should also be avoided. Light cream or off shades are suitable. In our tropical climate, bright and vivid colour could be well used for buildings and surroundings.

TRANSMISSION OF HEAT
Transmission of heat in a building is mainly through the roof and secondly through the walls. In order to prevent heat, the best approach is to provide shade as far as possible. The roof may have other light structures over it which may provide a cover. Hollow roof or double roof with through circulation of air in between, can also be used. Side walls which get direct sun, can be well shaded by trees properly located. Other means of shading by fenestration could also be used as in the case of the residential quarters of the American Embassy at New Delhi.

FOLIAGE
Growth of foliage on and around the building, properly landscaped, will help considerably for appearance and coolness. Who is not happy and delighted to see such creations of nature. In mild and sunny climates, abundant use of the same could be made in proper harmony with the building.

AIR-CONDITIONING
The use of air-conditioning helps in keeping the heat and dust out. Wider use of it could be made if plants for the same are manufactured in India. Where this is used, windows would be few and large glass surfaces avoided. This will have its effect on the external expression of the building. Due to psychological reasons, it may be desirable to provide sufficient openings so that outside view is available and the sky visible.

Solar energy is also used for heating and cooling. Shortly this may come in common use, and reflecting surfaces will have to be provided on the roof tops, along with the arrangement for storage of energy. This will provide a new look to the roof tops.

TRADITIONAL FEATURES
The various features which are noticed in our ancient buildings are mainly the outcome of climatic conditions. Projected chhajjas for shading the walls have been used. Balconies are used for sitting-out purposes where free breeze is available. It also casts interesting shadows on the walls. Perforated jalis which cut off glare and sun rays and admit breeze and also provide privacy, are freely used. Water pools and channels, fountains and sprays of water are common features which not only delight the eye, but create a cool atmosphere in dry and hot climates. Other features in the tropical countries are the domes and minaretes, which create an interesting skyline against the clear blue sky. Rooms with thick walls and smaller window openings to keep the heat and glare out are convenient for summer, and also keep the cold out during winter. Open sitting-out verandahs and courtyards provide living spaces when the weather is pleasant. All these features indicate a true expression of climatic conditions.

MODEM APPLICATION
Interesting types of jalis, precast box fenestration and perforated walls can be used with advantage and are aesthetically pleasing.

Other interesting expressions which our buildings in tropical climate can take, are the provision of open courtyards and shaded verandahs, which would give a feeling of openness. It will also give pleasing satisfaction to human needs by creating cool and open-to-nature atmosphere. Perforated or fenestrated devices used vertically and horizontally to provide shade and admit air, are very desirable. To this could be added water pools, cooling sprays and such other methods. The American Embassy building at New Delhi is a good modern example using such devices.

Disclaimer: The information provided over is collected from various publicly known sources viz, websites and documents which is provided for information and knowledge purpose only. It ought to be considered as a guideline and not as absolutely certain. For more authenticate details please visit respective website. While care has been taken for groundwork, no responsibility is accepted for the accuracy of whole or any part.