Laterite: The Bedrock of Goan Architecture and Identity

Laterite, the reddish-brown stone woven into the Konkan landscape and identity, is undervalued and over used. Its economic and cultural significance inspires us to innovate, developing sustainable methods that honour tradition while being mindful of Goa's ecosystems.

Written by Shivangini Tandon and Kshitija Mruthyunjaya

It is impossible to picture the Goan natural and built environment without laterite. If you have lived in or travelled to the Konkan region, to which Goa belongs, you would have seen this reddish-brown material all around you. More than just a building material, laterite is inextricably linked to the identity and aesthetic of Goan architecture, representing both the region's geological heritage and its architectural ingenuity.

Laterite is a type of soil and rock rich in iron and aluminium, formed in hot and wet tropical areas through intense and prolonged weathering. The Konkan region, including Goa, was geologically once an extensive laterite belt, which has been dissected by rivers and erosion over time, creating a landscape of elevated tablelands and valleys.

Laterite plateaus are important biodiverse ecosystems but are often classified as wastelands, making conservation difficult. Photo: Dr. Raju Kasambe

Distribution of key lateritic tableland (plateau) regions of Goa. Source: Mike Widdowson

Laterite's evolution as a building material

Historically, laterite was used judiciously in construction. "Laterite was a valuable material, it wasn't visible abundantly like how it is now. It was used minimally," recalls Dr. Maria de Lourdes Bravo da Costa, PhD, retired Assistant State Librarian from the Goa State Library. Her words offer a glimpse into a past where laterite was treated like a precious resource, standing in stark contrast to its widespread use today.

Found in abundance across western India, laterite has become an essential building material due to its durability, strength, workability, and thermal properties.

Architect and educator Tallulah D'Silva has been building with laterite throughout her 25+ year career.  She points out that modern construction typically uses laterite stone with cement mortar and sand, while older constructions used lime mortar. Using lime also makes structures easier to repair. Her approach is to leave laterite unplastered on external surfaces while using lime plaster on internal walls.

Although many Goan architects work with unplastered laterite, there have been some questions around this practice. Historically, builders overcame laterite's porous nature by plastering the outer walls with lime, protecting the stone from the elements and managing indoor humidity. There has been an ongoing debate around whether Goa's most iconic building, the Basilica of Bom Jesus, should be plastered for preservation[1]. The condition of the Basilica has brought to fore the vulnerability of exposed laterite in Goa’s increasingly erratic monsoons.  

The Basilica of Bom Jesus, Old Goa. Now well known for its red appearance, the Basilica was stripped of its lime plaster in the 1950s. Photo credit: Yulan Libram D'Costa

Ecological Toll of Illegal Quarrying

The construction boom in Goa has dramatically altered the laterite landscape. Angelo Costa, in his book "Lived Heritage, Shared Spaces," describes how laterite quarrying has evolved: "Very often many [quarries] were not far from the river banks so that the blocks could easily be transported over the river. With the improvement in transportation by land, this logic was considerably altered." Today, quarries dot the Goan landscape, chosen for quick extraction rather than sustainable practices. Laterite quarrying along with other mining activities in Goa have been banned for several years [2]. As a result, most of the laterite is brought in from neighbouring states. However, there are several recent reports of unregulated [3] and illegal extraction of laterite stones in Goa [4]. Unauthorised quarrying is causing severe environmental degradation, damaging agricultural lands and water resources, threatening archaeological sites, and posing hazards to human and animal life. 

A laterite quarry. Photo: Wouter Hagens

Alternative Building Materials and Methods

Tallulah D'Silva, concerned about the environmental footprint of laterite quarrying and transport, has started to build with excavated soil and mud. She is increasingly working with techniques which use rammed earth and poured earth construction methods.

The scale of laterite use becomes alarmingly clear when examining construction and demolition (C&D) waste in Goa. According to TERI’s Circular Economy Strategy for Goa, a typical 180 m2 building generates a staggering 400 MT of debris, with laterite accounting for 65% of this waste. Overall, laterite and similar blocks make up 58% of all C&D waste in the state, underscoring the urgent need for better waste management and recycling practices [5].

At Solarpunk Futures, we recognise laterite's value as a building material but also the fact that it represents Goa's geological and cultural heritage. While we are using the stone in some ways for its strength, we are also exploring ways to repurpose laterite waste and quarry residue as fillers in new construction materials. This approach not only reduces the need for virgin materials but also helps divert waste from landfills, promoting a circular economy.

In our pilot project in North Goa, we are working with Greenjams on repurposing the demolition waste and excavated soil from our site into AgrocreteⓇ blocks for our building walls. Another promising avenue we are researching involves creating composite building materials by combining lateritic soil waste with other waste streams, such as plastic and natural stone offcuts.

As Goa continues to grow, the laterite story serves as a poignant reminder of the delicate balance between progress and preservation. The challenge lies in honouring Goa's rich architectural heritage while embracing sustainable practices that protect its natural beauty and resources.

Understanding local materials like laterite serves as both a warning and inspiration. It calls us to recognise the value of our geological and cultural heritage while pushing us to innovate and find better ways to build. 

Feature image credit: The Balcão

Further Reading:

The Geology of Laterite:

Evolution of Laterite in Goa, Mike Widdowson

Laterite Mining:

Mining ban in Goa, The Hindu

Circular Economy in Goa:

Strategy for Fostering Resource Efficiency and Circular Economy in Goa, TERI, EU, Government of Goa The case of unplastered laterite in the Bom Jesus Basilica: https://thebalcao.com/bom-jesus-basilica-should-it-be-plastered-or-not/