Nalukettu - The Heart of a Tharavad

From asking a fellow Malayali "Naatil evidaya" to hitting the road to our ancestral home for a break, we seek solace in going back to our roots.

A striking shape of Kerala’s heritage homes (Tharavad) is ‘the courtyard house’ (the nalukettu). Although cities have startled us with its skyscrapers and contemporary habitats, what is it that keeps the traditional nalukettu alive and looked upon still today?

What is a nalukettu?

Nalukettu or ‘courtyard house’ is the most evolved form of the classic residential architecture of Kerala.

‘Nalu’ means four and ‘kettu’ means halls built in Malayalam. Thus, a nalukettu is a building where a rectangular or square courtyard left open to carry in light and ventilation connects four blocks with high-pitched roofs together. It was built for large families of the traditional tharavadu. The tharavadu tradition was a system where noble families who prided on their maternal lineage lived as joint families for generations under one roof.  

Nalukettus are mansions that satisfy people’s functional and socio-cultural needs. The design considered the region’s geography and changing climatic conditions and used locally sourced building materials. The stapathi (master builder) sets out the plan as per the norms and principles stated by the ancient books of Thachu Sasthra (Science of carpentry) and Vaasthu Shashtra (Science of architecture and construction)

The plan is a rectangular, sunken, sky-open living space called ‘nadumuttam’ surrounded by halls built in the cardinal directions. The four halls are vadakkini (Northern Block), thekkini (Southern Block), kizhakkini (Eastern Block), and padinjattini (Western Block). These halls were divided into several rooms for different activities. This arrangement of outdoor and indoor spaces provides a flexible natural environment for social interaction.

Nalukettu was one story or were two to three storeys or mallika high, depending on the household. However, larger tharavads demanded larger structures, then they repeated the halls enclosing courtyards forming ‘ettukattu’ (8 halls and 2 courtyards) and ‘padhinarukettu’ (16 halls and 4 courtyards). Some notable examples of the nalukettu are the Mattanchery Palace at Kochi, Kerala, and the Taikottaram of the Padmanabhapuram palace near Kanyakumari (then part of Kerala), Tamilnadu.

The Design of a Nalukettu House

If these nalukettu houses were of only traditional importance, they wouldn’t have inspired architects in designing today’s house. Even after the notable decline in joint family systems, the current trends in residential architecture encourage modern adaptations of nalukettu features. We feel at ease in a nalukettu with no air conditioner, which is quite the opposite in today’s houses.

Upon entering the house by the Padipura (entrance, a stepped gateway with a clay-tiled pitched roof) we can find the house to be located at the center of the plot, allowing clear passages for airflow around the site. We can often find someone chilling at the poomukham ready to welcome us. 

Poomukham or the portico is the entrance to the interior of the house. It has a sloped tiled roof supported by pillars. The houses had a high plinth to prevent water from entering the house during monsoons. The poomukham is lined with charupady or the iconic wooden seating where we can sit back and relax with a cup of tea. The serene natural environment makes them hubs for socializing with family members. We can find a corridor running along the sides of the house, connected by the poomukham, called the chuttu verandah. These chuttu verandahs are adorned with lamps hanging from the roof and provide shade to the interior spaces, reducing direct heat gain.

The Ambal kulam  or the pond is found at the end of the chuttu verandah with lotuses in any home at Kerala. These ponds were built with rubble to synthesize the energy flow while keeping its surroundings cool. At the center of the house, we can find the nadumuttam, the courtyard that anchors the house. This allows us to experience changing weather conditions, be it rain, strong gushes of wind, or the warm morning sun while at the comfort of our home. They allow proper ventilation and serve as spaces for human interaction. A tulsi plant placed at its center is usually worshipped. This plant also acts as a natural air purifier that enables a healthy living environment.

To put it in a nutshell, the house is planned by dividing the blocks surrounding the courtyard into rooms, sandwiched between corridors on either side, the chuttu verandah on the outside, and the verandah connecting the courtyard inside. 

Natural shade and wind flow

The advantage of courtyard houses lies in the fact that there is maximum use of daylight and sufficient room for ventilation. This allows for the light warm air to rise and escape the building from the open courtyard, creating low pressure inside. The pressure drop draws cool winds into the house that provide passive cooling and maintain thermal comfort. Thus eliminating the need to use electrical appliances for cooling results in low energy consumption. The figure below is a conceptual depiction of the functioning of courtyards.

The interior spaces are designed to use semi-open spaces as living rooms. They are located on the southeast and south side to avoid the harsh direct sunlight from the west, the eaves in the south provide nominal shade and reduce heat gain from the south where the sun is at a high angle.

The kitchen is located at the northeast corner to avoid the monsoon winds that travel from the southwest to the northeast, carry hot air from the kitchen to the rest of the house. The puja room is found at the northeast side or eastern side of the house with the idols facing the east or west.

We can find the bedroom in the western part of the house, as they were used only at night we need not worry about the direct western sun. The windows in these rooms were in turn shaded by pitched roofs restricting direct sunlight.

The interior corridors give shade to the rooms and offer protection from the rain with their sloping clay-tiled roofs.

Locally sourced building materials 

The materials used for construction differ depending on the region. However, major materials used were laterite stone as masonry bricks, granite for foundations, stone for pillars, wood for ornated pillars, paneling and flooring, clay roof tiles, bamboo, red oxide for interior flooring, lime plaster finishes for walls, and unfinished granite outdoor flooring. Mud plays a major role and is used as a mortar, as bricks for walls, and for making clay tiles for roofing. The walls are painted in white or light colors to minimize heat absorption. As these materials are locally sourced natural materials, they are eco-friendly and reduce transportation costs.

Why do nalukettu houses have high-pitched roofs?

The pitched roof has an attic with a roof beneath. This attic acts as an insulating layer filled with air, which prevents the transfer of external heat to the rooms below by conduction. The attic has a tiled roof with openings that allow hot air to escape.

Courtyard houses in the current urban setting 

Various architectural studies have proved that the passive design strategies of nalukettu houses have been successful in maintaining comfortable indoor conditions at all seasons in southern India. The flexibility of modern courtyards in moving from children’s play area to a party area overnight offers a wide range of opportunities for human interaction.

In the current urban setting, courtyard houses with indoor gardens prove to have a large impact on maintaining a comfortable indoor environment. The steeply pitched roofs and overhanging eaves allow easy discharge of rainwater. Owing to the heavy monsoons that Kerala has been facing the past few years, it is important to install proper drainage for the courtyard to avoid flooding the house.

A well planned and well-executed drainage system can not only save the house from flooding but can also efficiently harvest rainwater that can, in turn, replenish groundwater in the growing crisis of freshwater scarcity. Integrating current technology with these passive techniques can provide cost-effective measures to achieve ideal levels of human comfort in today’s houses.