SUSTAINABLE FACADES

A SHORT HISTORY OF SHELTER & FACADE

What came first “the roof” or “the wall” is an age old question in the history of shelter. From the earliest of times “shelter” for any man or animal meant a roof over the head, protecting it from weathering elements like the sun, rain and snow.

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Image 1: Native American Dwellings    Image 2: Stone Houses in south America    Image 3: Caves of Guyaju China
04The walls came in more as a protection from the threat of animals and warring tribes and eventually from the need of social privacy. And as the enclosure was formed, then arose the need for comfort within the enclosure. Mans relationship with climate and enclosures is an exploration since antiquity.  In every climatic zone a unique enclosure was made to adapt to the weathering and hostile elements. At first this enclosure also called as the building envelope, was responding to specific functions but as and when civilizations progressed, embellishments and decorations were carried on the facades. These became symbols of prosperity and carriers of culture and heritage. Some of the civilizations to be noted being the Greek or Chinese temples or even the more recent Moslem mosques and palaces. This is where the public buildings presented themselves into important urban spaces with uniformity and notable character. Facades abutting the street were transformed and those abutting alleys were left unattended.  But some unique installations like the Flatiron Building of New York, which stood at the corner of two major streets was presented with due importance. In spite of this differentiation, the facade still served as a primary provider of  daylight and ventilation in warmer climates and protection from cold in the colder climates.

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Image 7 & 8 : Flatiron Building in New York

FUNCTIONS OF A FACADE

Rural Context : Interestingly, historically  interior spaces of rural dwellings, across the entire world  were unusually dark. Light was controlled by smaller openings. This was either dictated by the technology of construction or by the function of the space. This also gave an insight that most functions were done outdoor or in semi outdoor spaces like courts and courtyards.

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Urban Context: However historical cities as well cities of the present require more and more functions to be held within the dwellings due to density of buildings. Gradually, vertical stacking of functions led to taller urban structures, space between the buildings reduced and there was an increasing requirement for visual comfort and thermal comfort i.e primarily light and ventilation for almost all times of the day in the interior spaces. This revolutionised the facade and serves as the primary function even to the present day.

FROM THE WALL AND WINDOW TO CURTAIN WALL:

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Image 11: The :Lever House /building in New York, the first to make use of the curtain glass


The FLIP SIDE
 For centuries the design of the building envelope, i.e the wall roof window and floor was driven by the prevailing construction technology like stone, earth or wood and the primary need of comfort from heat or cold. This also restrained the size of the openings and the thickness of walls, and added weight and bulk to the structures. However the industrial revolution led to the invention of the curtain wall, for the first time an innovative way of using glass. The entire wall was replaced by the curtain wall for the first time in the The Lever House building in New York.

As much as this reduced the bulk and volume of the buildings and allowed for penetration of natural light, it also became a weak envelope in terms of its resistance to excessive heat or cold and started functioning more like green houses. A likewise revolution in material was concrete which replaced all traditional age old materials and became the new popular construction technology and infill material. The past 100 years could be said as the age of glass and concrete and steel. It enabled the builders and designers to build the buildings and structures of their dreams, however it also led to the newer buildings having lesser resistance to heat and cold. This led to the inventions of the artificial cooling and the artificial lighting technologies. Rapidly, building that were almost near zero in their energy consumption and self sustainable began to need large amounts of energy to perform.

80% of the buildings energy use was during its operational phase, mostly arising from its need for artificial lighting and artificial cooling or heating.  Environmental degradation, and unsustainable operational energy bills began to question the facade performance and once again questions began to be raised !!! And THE FACADE AS AN ELEMENT OF DESIGN BEGAN TO BE REDEFINED!!!

THE FACADE REDEFINED:

Some of the primary questions which led to this enquiry were:

  • What is the function of the building skin or envelope or facade ?
  • How do these elements that form the facade impact the building form function and design?
  • What does the facade convey to the user, what is it relationship to the user in the external environment and internal environment ?
  • Does the facade of the building participate in the large scheme of urban design and form ?
  • Finally what is the energy consumption of the building due to the facade during the entire life ccycle of the building ?

Thus the Facade moved from energy guzzling element to energy conserving, and from energy conserving to energy generating element of the building envelope.