The idea of sustainability in the building sector must co-exist within the larger holistic concept of socio-economic, cultural and financial sustainability and more so, in the Indian context. Consequently, the understanding of sustainability, need to be redefined by expanding its boundaries.
Sustainability is like old wine in a new bottle. Along the journey in time, established ideas got diluted or lost and through the changing eras many new issues have been thrown up. The major impact is that of depleting resources as against the increasing needs and the consequent ecological footprint that is getting threateningly large and completely unmanageable. That is why we have to embark on this active agenda of pushing sustainable practices.
What is Vernacular Practices?
Vernacular architecture is reviving the old forgotten building technology. Call it architecture without architects or simply tried and tested building techniques, which have been developed, perfected and handed down through the centuries, often built by the actual inhabitants. In building parlance, sustainability is building in a way that present usage patterns and do not compromise the future. It has two basic approaches in current connotations:
• Naturalistic or the passive
• Active or artificial
The active measures are energy driven and can be seen largely as what could be termed as “second level” or sometimes even as remedial measures. The naturalistic measures use first principles or passive designs. What is required is to, start with the passive measures and use active ones to supplement whatever that cannot be overcome in specific situations.
The Modern Context
The definition of good architecture as perceived by the masses, both the existing urban and the migrating population, has to change; the latter have aspirations of moving into a “pucca” structure from their informal homes/slums. They do not really appreciate the values of their vernacular techniques or self-designed and built homes. All this simply translates into a desire for a brick/reinforced concrete or metal, glitzy glass and aluminium structure, which, as per their understanding is “the thing to possess”.
In the past, Indians had understood the idea of overall sustainability very well. The frugal living style, ingrained habits of recycling and the more pertinent “as built encyclopaedia” existing around us is ample proof of this fact. However, within the backdrop of growing urbanization, we are in a scenario where buildings are getting more and more context-less in every sense including the environmental and raising concerns of sustainability and even identity. In the Indian urban scenario, the major chunk of the built stock built by developers often falls in the category just mentioned. The onus is on the architectural community of practitioners, policy makers, writers, critics and researchers to change current practices individually and collectively.
Is Vernacular sustainable?
The country has a rich vernacular legacy to draw from and its greatest strength is its adaptability and timelessness. Our rich vernacular tradition actually starts from the natural settings of the site/city and responds to metaphysical concerns, climate, local skills/materials and appropriate technology. More importantly, it is a passive approach and thus less energy intensive; these are proven technologies and often scalable.
There was always the use of Passive micro climatic manipulation by making use of water bodies or fountains in climatic devices like courtyards to modify adverse climatic impacts of hot and dry climate or the use of thick walls to introduce time lags in the fluctuating diurnal cycle. For instance, the courtyard home was the prevailing Indian planning model before the advent of western ones. It was very versatile as a climatic device, an outdoor cooking/dining, sleeping/living area and for festivities. It was adaptable to any climate across Indian cultures and geographies. That explains its survival.
Most vernacular buildings are well lit and ventilated/climate responsive as to avoid or minimize the use of artificial devices.
Proportions: A hot humid zone should have courtyards with more length and breadth compared to height where the basic climatic strategy is to cut out heat and provide air movement A hot dry climate needs more height to provide shade. It allows cool air to settle down in the summer and allow outdoor living in the sunnier parts of the courtyard in winters.
Light: It is such an important aspect of architecture both in terms of quantity, which has a bearing on energy usage, as well as in terms of its qualitative aspects like glare. A lot of religious buildings like temples and masjids had fenestration/façade engineering done to control and manipulate light by means of devices like jalis or double windows with wooden louvers.
Air-conditioning: Palaces and forts made ingenious use of water to cool the building envelope. The walls would have water pipes embedded inside to cool down the masonry walls. The water was cooled naturally by making it run over surfaces and exposing it to the atmosphere.
Ventilation: Wind scoops also allowed the entry of breeze into the hot desert zones; micro climatic modifications include the introduction of dripping water by installing a pot at the top of the scoop.
Water Conservation: The Kanheri caves, (Mumbai) built as religious retreats for the Buddhist monks, show the presence of channels cut across the external rock cut faces to carry down water into underground storage tanks. More recent example is that of the underground tanks (“Tanka”) in most of the traditional houses of Gujarat. Water is collected through a copper pipe and stored in the stone or lime tank with a cover and can supply clean potable water for a midsized family for a year; that is a huge advantage in a hot and dry zone.
The “Warli” home in Maharashtra, built with “karvi” walls using local materials i.e. mud plaster on a framework of branches is climate responsive. It has a light external envelope, which loses heat quickly and allows air movement, appropriate for hot and humid climate.
In Rajasthan, the traditional shelters called Bhoonga, built around open courtyard forming clusters can withstand earthquakes. The circular form ensures minimum exposure to the external elements, which is extreme hot and dry desert climate. The smaller openings control entry of light, heat and winds and the building materials are mud for the walls and thatch for the roof.
The Padmanabhapuram palace is representative of the local architectural style in Kerala. It is well suited to the climate with multiple courtyards to allow air movement across the complex and meticulous fenestration detailing to cut through the glare. The gleaming black floors even after a period of about 400 years are said to be made using a mixture of different materials like, burnt coconut shells, egg whites, plant juices etc.
The modest building structures in Goa are usually plastered in lime or a mix of lime and earth or are left un-plastered with huge sloping roof overhangs to combat the rain and the strong sun. When the house gets dilapidated, it literally crumbles down to earth and brings the building materials back to their organic and natural state, “completing the loop”. The wood used is often the local jackfruit wood
What is evident in the examples is the seamless blend between the use of locally available materials and skills picked by the residents in building and maintaining their own homes. Local materials are manipulated to suit their lifestyle and climate without impacting the environment.