Sun Shades of Building






In tropical regions of the world, the main consideration in the building orientation with respect to the architectural composition is the protection to be given to the components of the structure which are exposed to the heat of the sun. The devices which are used in the building or home design, for this purpose are known as sunshades. Sunshades not only provide protection against the sun but prove extremely useful in guarding the structure against the effects of high wind and heavy rain at home. The sunshades device may be classified under two main heads.

1. Natural sun shading devices used for the Building 
2. Artificial Sun shading devices used for the Building


1. Natural Sun shading Devices used for the Building

The most widely used natural means of sun shading is to grow plants and trees at suitable places around the home or building. It is observed that trees of deciduous variety provide shade in summer when it is most required and also allow sun rays to enter the building in winter when it is most desirable. Planting of the trees should be such that they do not interfere with the circulation of air around the building and further, they provide desired shade at the desired time

2. Artificial Sun-Shading Devices used for the Building

Artificial sun-shading devices used in the building can be grouped in the following three categories

(i) Louvers

(ii) Overhang

(iii) Screens.

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(i) Louvers. Louvers ordinarily mean a series of inclined horizontal slats fixed in a window frame or any other opening in the building. This facilitates to admit the passage of air and to exclude the sun-rays and rain. The louvers can be an exterior type or interior type. Exterior type louvers are also known by another name, the Sun breakers or in French 'brise Solerl'.

(a) Interior lowers. In this type, the shutters of doors and windows are provided with louvers in the building. They are arranged at such an inclination that horizontal vision is obstructed. The louvers may be movable or fixed. In the case of movable louvers, a vertical piece of timber is provided to which louvers are attached through hinges. The upward or downward movement of louvers can be carried out with the help of a vertical piece of timber. The slope of the horizontal slats should be kept towards the outside so as to prevent the entry of rainwater at home.

(b) Exterior louvers or sun breakers used in the Building. The Sun breaker may be used either as horizontal or vertical and may either be folding or fixed.  Horizontal louvers when used in series in the form of overhangs permit air circulation near the wall. The vertical louvers build it to set either perpendicular or inclined to the wall depending upon the Building orientation. They are found most effective on the East and West sides. A combination of horizontal and vertical sun breakers prove most effective for Southern Building orientation. Such sun-breakers are also known as egg-crate or honeycombed shades. The sun breakers can also be used effectively in combination with concrete hoods or over hangers provided with window lintels. Vertical louvers if kept 15 cm away from the main Building wall help in maintaining better air circulation.

(ii) Overhangs used in the Building. An overhang means an element of construction projecting outwards beyond the external vertical face of the building wall or facade. It is one of the most effective artificial means of sun-shading used at home. Overhang when formed at floor level by projecting roof slab or independent slab and there is a plinth or floor below the overhang it becomes a verandah or balcony. Overhang when provided at the lintel level is also known as a sunshade. Louvers as sun-shades hung from overhangs are found most efficient where protection is required from the low sun. A similar advantage can be achieved through sunshades, canopies provided above building windows. The horizontal overhangs are most effective towards the South but they are not that effective particularly on Western-side as they give very little protection against the after-noon Sun. So Building orientation plays an important role in the Sunshades of a building.

The exterior louvers or sun breakers can be used in combination with overhangs in the buildings. This arrangement helps create the artistic and pleasing appearance of the structures. When the vertical drop of the Sun beakers is extended up to the sill level of the window and when horizontal cum-breaker is also provided at sill level besides an overhang at lintel level. Sometimes Shades are also built with vertical drops at the free horizontal end of the shades. This arrangement increases the effectiveness of the horizontal shade against high sun and rain.

(iii) Screens. The screen is another method of sun shading used at home. It may either be attached to the building or be kept away from the building the simplest sunscreen is the provision of wooden shutters in doors and windows. Adjustable and removal awnings, horizontally sliding shutters can also be used as sun-screens for home windows. Awnings are found most suitable for southside windows whereas sliding shutters are found most suitable for shading Westside building walls in summer. Screens can also be used detached from the building. Freestanding devices like fences, trollies work, screen walls may be used as detached screens in the home. They can be given artistic touch to improve the appearance of the building. Modern practice is to use a screen wall placed independently as a second wall before the glass or window wall at a clear space of about 75-100 cm.

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