Knowing daylight and shadow patterns round the year is helpful, says SATHYA PRAKASH VARANASHI
Often we see design ideas going through a paradigm shift, nearly to the opposite ends. To realise this phenomena, look at this — from the past practice of building for shade inside the house and outside on the walls, today we are seeing buildings washed with light everywhere. Accordingly, windows on the walls have become larger, external walls are exposed to direct sunlight and skylights have been introduced.
While the theory of light is desirable, the resultant heat built-up is a nuisance no one can live with, hence the need for ideas to shade the building.
During the early years of modern architecture in India, simple projected chajjas were introduced. As shading devices, though without specific considerations of direction, depth of projection and materiality, they continue to be popular in India.
Indian traditional designs did not use an external skin, but provided deep overhangs like at Fatehpur Sikri or built external walls as perforated jaalis to reduce heat built-up as found in Jaisalmer. Or positioned wooden louver-based features as walls as seen in the Padmanabhapuram Palace.
For every region now there are solar charts – specifically locating the sun in technical terms like altitude and azimuth.
It is possible today to calculate the exact pattern of shade for any given time using manual formulae or computer simulated software driven programmes. No single solution can serve year-round needs; hence we need to think judiciously to derive maximum benefits across the seasons.