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THE GOOD EARTH

THE GOOD EARTH
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The way animals build their nests has always fascinated and piqued my curiosity. These nests range from an anthill with its intricate maze of tunnels leading to chambers way below the ground with spires in clay complete with ventilation vents to let cool air in and hot air out to the arduously sewed nest of the tailor bird or the ingenuous structure built with leaf litter by pagoda ants on tree trunks. Other homes include the swallow’s clay pouch often seen under the soffits of buildings, bridges and such structures painstakingly constructed by sticking balls of field clay. There is also the pot shaped structures joined together in a bunch by the wasp and the geometrical maze of the a complex beehive. All these homes exemplify an adept knowledge of building with materials easily available in nature and which can be  reused or recycled and cause little environmental pollution. All species in nature build and live sustainably, maintaining a balance that humans have found difficult to emulate. While our ancestors, having studied this practice, did the same, our current examples pale in contrast!

Besides using natural materials, the physical characteristics of the site are conserved. Hill slopes and natural drainage are left intact, unlike our current practice of flattening out every site. While new materials have been revolutionary, the way we use them is still limited as we utilize artificial materials that cost more, have a shorter life and need equally expensive systems to run them and make them comfortable to users. This is negatively impacting the environment and increasing the carbon footprint of buildings in particular.

So what really is a green or eco-friendly building?  The answer is when it conserves energy, both embodied and external, uses renewable or reusable resources and has a minimal impact on the environment, not only during the construction of the building but also during its lifetime. Does that mean that traditional structures are more environment friendly than their contemporary counterparts? Without a doubt! Traditional systems and materials used in construction have proven to be environmentally sound besides being energy efficient and thus sustainable compared to current technologies that use manmade or industrialized materials.

Let’s analyze the various components of traditional buildings and construction techniques that prevailed across Goa. Most of the materials used were sourced locally, easily available, durable and mostly reusable.

Laterite: A principle building material,a red coloured, ferruginous and porous natural rock abundantly found across Goa and locally called chirre. The top layers of this monolithic rock are ideally suitable for building wells as it is comparatively harder and its grain denser, allowing for easy percolation of fresh water from natural aquifers. It is extracted manually with a pickaxe and hardens on exposure to the sun. Most foundations and walls were built using this material. Flat lintels or arches to span doors and windows were made using laterite stone. Laterite is economical, natural, durable, insulates and is reusable. Most of the city and town buildings up to three storeys high and the famous monuments of Goa were built using this red stone.

Mud or rammed earth: Building with rammed earth is the oldest technology  practiced since ancient civilizations. Laterite clay mixed with sand and straw for stiffness with minimal water content is cast and rammed in layers between wooden panels. Window and door openings and corners of buildings were lined with laterite stone. This is the most inexpensive form of building. Mud is a natural material, has good insulation properties, is energy efficient and is a reusable resource.

Basalt:  A grey hard rock, much stronger than concrete and abundantly found in Goa is mostly used to build roads and as aggregate in reinforced cement concrete. It is extremely good for foundations and was used in many old buildings and monuments in Goa. Basalt stone, a natural hard material, has insulating properties and is a reusable resource.

Load bearing construction: This was one of the earliest systems of construction where each unit of stone and corresponding wall bore its weight vertically downwards onto the foundation. The principle materials were granite, laterite or adobe bricks. Many masonry buildings  still stand tall. Modern materials like steel and concrete  are expensive, have a shorter life, are energy guzzlers during manufacture and construction and need equally expensive technologies to make them comfortable to users.

Arches and lintels: All door and window openings were spanned with masonry arches of various types and stone slabs or timber planks were used as lintels. These respond well to settlement while concrete cracks easily. Masonry arches are the oldest structural elements and are living testimony to their strength, durability and weather resistance. Arched bridges and viaducts built centuries ago serve as fine examples of this fact while concrete has a far shorter life span.

Lime mortar: Lime sourced from shells of shellfish was burnt at low temperatures to form chalk which on hydration produced a smooth paste and was mixed with sand to make mortar. Lime, unlike cement, is carbon neutral which means that while it releases carbon during its burning process of manufacture, it reabsorbs the carbon when water is added to it before use. It can be recycled, is biodegradable, uses less fuel during manufacture, is less polluting and saves on transport as it is sourced and prepared locally.

Slaked lime wash: While ‘white washing’ has been a common annual practice followed by all old Goan houses for centuries since  Portuguese colonization, it has now being taken over by new age paints loaded with toxic chemicals that have a huge impact on the environment and our health.  In a white wash, the diluted lime putty when applied externally hardens or crystallizes serving as a protective layer, besides imparting an aesthetic appeal. Oxides, indigo and ochre were added for colour. The new age paints  are non biodegradable, crack and flake easily, use non renewable resources, are energy intensive, contaminate water bodies and ground water and cause a host of environmental problems.

Timber: Roofs and intermediate floors were usually constructed with locally grown timber. Matti and teak wood were preferred choices because they were hardy and resistant to termite attack. Easy to work with and construct, timber, a renewable resource, was locally sourced  and so saved on transportation costs as compared to concrete. All one had to do was plant more trees.

Jack arch floors: This system of constructing flat slabs involves placing either wooden or steel beams across the shorter span with shallow brick masonry vaults in between and filling over with earth or screed to make a level floor. This system is economical, uses natural materials, can be reused and, unlike concrete, insulates the indoor spaces from excessive heat intake.

Terracotta roof tiles or Mangalore tiles: Terracotta clay tiles called Mangalore tiles and country tiles were used as roofing materials. These allowed for air circulation and insulated indoor spaces. They were locally manufactured using local raw material, were reusable and biodegradable. Vent tiles allowed the hot air to escape, thus cooling the indoor spaces below. Glass panels interspersed at regular intervals let in natural light into darkly lit indoor spaces.

China mosaic flooring: Very common in old Goan houses, these were basically a reusable resource salvaged from ships carrying China that was damaged en route to India. It was used with aesthetically pleasing designs interspersed with oxide panels.

Wells, reservoirs and cisterns: These were built as systems to harvest rain water and recharge the ground water table.

Kitchen yards with reed plants: A tradition followed by all, the kitchen and bath water was often routed to a clump of wetland plants like banana, colocasia and canna indica which effectively absorbed all the sulphates and other chemicals in soapy water and filtered the grey water. Aeration of the water further aided its filtration.

Indigenous landscapes: Less manicured gardens and yards with local fruiting and flowering plant species grown around the buildings served as an effective buffer against noise, dust, heat and rain. These also provided timbers for various purposes, had medicinal uses and were both economical and renewable.

Although vernacular buildings do prove far more sustainable than their modern counterparts, some simple interventions do need to be incorporated to increase their energy efficiency in today’s times. This can be achieved by simply replacing ordinary light fixtures with CFLs as these conserve energy and also save money, replacing  old taps with low flow ones, and  using paints that have a low VOC. Harvest all the roof rainwater by routing it into an underground storage tank below any habitable room within the house or open space available outdoors. Rainwater is free, clean and a renewable resource. Use existing roof to harness solar and wind energy. Although area intensive and with initial high installation costs, this can be economical in the long run.

Remember, if we care about the environment it will care for us too and provide for all our needs. 

This article first appeared in Timeline Goa Magazine: Vol. 1 Issue 2 (Page 33).

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