Home sustainable home

By constructing ‘cool’ homes, architect Krithika Venkatesh aims to bring back the practice of using lime mixture
Home sustainable home

CHENNAI: While summer holidays now mean a getaway to exotic locations, in the earlier days it was a period to spend time in our ancestral homes, running around the cool verandahs and whiling away time sitting on the thinnai.

Trying to touch the huge beams; helping our mothers fetch water from a well in the backyard; plucking herbs that grew just outside the kitchen window; admiring the symmetry of the rooms; bathing in the cool breeze and sleeping on the cold floor — all these experiences made the brick and stone house an abode of love and care.

This is a page right out of architect Krithika Venkatesh’s childhood when she visited her grandparents in Kancheepuram. In the mornings, women would chat and giggle while spinning the colourful yarn, with the sun rays falling on the muttram (courtyard).

In the nights, she would sleep beside her grandmother in the courtyard and gaze at the stars. “We had huge muttrams because there were no private rooms. The home was made of lime and was very cool. I loved to visit and stay there,” she shares.

Research and revival

These sojourns increased Krithika’s curiosity about architecture. She graduated with an architectural degree in 2018 from Mohamed Sathak AJ Academy of Architecture. In 2016, during the third year of a five-year course, she pursued her internship at Peoples Architecture Commonweal. “My first assignment with Sudhir, my mentor then, was to go to different sites where building materials were manufactured,” says Krithika.

The visit started from Coorg, along the Kaveri basin, and ended at Nagapattinam. They came across cement factories, river sand mining, bauxite mining, and other construction industries. “We saw the level of degradation to the environment that had happened because of these construction projects.

River sand mining, which had clearance of digging up to three feet, had gone up to 13 and touched the clay. People in the neighbourhood started complaining about water shortage,” she says. The team came to an understanding that the construction industry was causing damage to the environment and labourers involved in the occupation.

“Our solutions always address the symptoms and not the root cause. And as architects and engineers, we are not seeing the bigger picture,” Krithika points out. As a result, her study report focussed more on the alternatives, of which, one was substituting cement with sustainable limes, a practice that is a part of our traditional values.

“In earlier days, we had mann veedu, and the masons were from a community that was looked down upon. They did not have the privilege to build one for themselves. The same happened when we evolved to lime and to cement after the Industrial Revolution,” she adds. Hence, she travelled to around 42 villages across south India, to explore artisans, as they knew the technique well.

Planning and plotting

Gathering around 90 workers, including 45 women, Krithika started Studio for Earthen Architecture in December 2018. Since then, the team of six (three architects and three craftsmen) has built 14 sustainable houses and is currently working on three outside the city. In these projects, pre-planning takes four months. “We start from site study, do a soil test and understand the hard soil, then plan how to do the foundation. For this, we sit with the client, understand their life and lifestyle,” she explains.

The first part of designing involves site study analysis and understanding the prevailing wind direction. Then the foundation of stone or brick masonry is laid. For the plinth beam — to tie up the structure — stone slabs are used, so they do not shake during an earthquake, and for flooring handmade tiles are used as they are good for the feet. “The structure has a Madras Terrace Roof. It’s called so because it’s predominantly done in Madras and was named by the Britishers,” shares Krithika.

On a hot summer day, Kirthika invites me to a house that the team is building at Mambakkam. As the city had just hit the 40-degree mark, the temperature difference inside the house was evident. Dhananjeyan, a mason from the construction site, says, “Our tradition lives with this practice of building home with lime. Old houses use these kinds of techniques; lime, mould stone, and Madras roofs. Having constructed such houses 40 years ago, the trend is coming back. Building lime homes for the last eight years gives me happiness because it is not just a mere structure but an art.”

The other old practices used in their sites are courtyards, the cross ventilation technique, and lesser use of water and electricity. Courtyards are usually placed on the northern side of the structure so the hot air, which is light in weight, goes out of the building. This is called the stack effect. There are also porothem blocks, which help the hot air exit. To do so, all the openings are aligned. “Cross ventilation is another technique where the velocity of the air increases when the openings are very straight. The incoming air’s entrance is bigger, so, there is a little compression and the velocity is better,” she says.

Building benefits

In all their projects, cement is replaced with lime, both by-products of limestone. She sources these stones from a lake near Mambakkam, calcinates them, and mixes them with kadukkai and palm jaggery. This mixture is fermented for three days before use.

Lime is degradable and eco-friendly. While cement houses set in 28 days and last for 60 years, the degradation begins in 45 years. With houses made of lime, the setting period is between three months and seven years, and they are long-lasting. “The processed lime is Calcium Oxide (CaO) and it takes the carbon dioxide from the air and becomes calcium carbonate that’s the exact state of the limestone,” says Krithika. As defined by WHO lime does not promote sick building syndrome — situations in which building occupants develop symptoms of illness or chronic disease. This laborious and tedious process costs 40% more than cement houses.

After providing the city with sustainable homes, Krithika and team are conducting regular workshops for Chennaiites to understand the process of constructing buildings with lime, and the health/environmental benefits, in a move to bring back this architectural practice. The next workshop will be held on Sunday. If you are someone who loves Chennai but would like to have cooler summers, head to this workshop to learn all about sustainable building solutions.

Workshop on Vernacular Architecture will be held on June 9 from 10 am-6 pm at Plot 75, Janani’s Citrus Country, Mambakkam

For registration, Call: 9943754403

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