A chance conversation with a distant family member led me to Palayil, the name bestowed on my ancestral tharavad. The latter is the name given to a house designed around women. Ours had stood, in some form, since at least the 17th century. My great-grandmother, Palayil Sreedevi, was the last woman in my line to live in one. It was in the southern Indian village of Tholanur.

My great-grandmother belonged to the Nair community, a matrilineal caste with its origins in the state of Kerala. Historically, it was a martial nobility that served royal dynasties. For centuries, Nair boys left home at 12 to train as soldiers before being dispatched to serve the Travancore royal family. When men returned, they often slept in outhouses – satellites to the tharavad of women.

I have spent several years researching societies around the world where women built systems, communities and institutions of their own, for my book Herlands: Lessons from Societies Where Women Make the Rules. The title nods to Charlotte Perkins Gilman’s feminist novel Herland, imagining a society governed by women, although my interest was in the real communities women built for themselves. I had hoped my journey would end with Palayil, and it did, but not in the way I had imagined. Palayil had been pulled down more than a decade ago, as the matrilineal system my great-grandmother was raised inside unravelled, dismembered by laws written by many men.

When I finally went looking for it in 2024, I walked across acres of paddy and found only a groundkeeper’s house, a serpent shrine, an old gate and the neighbours who remembered it. The tharavad in its glory exists now only in memory. But its grammar – the rooms, the routes, the bodies it was built to hold – survives in others like it across Kerala.

This matters beyond my own family history. Today, 23 June, International Women in Engineering Day celebrates the contributions women make to the design and construction of the world around us. The tharavad raises a complementary question: what happens when buildings are designed around women’s lives in the first place? While the houses were constructed by male artisans, they were engineered to accommodate women’s needs, rhythms and authority. Looking back at them reminds us that the built environment is never neutral; it reveals whose needs, experiences, and lives are valued enough to shape design decisions.

The house was a nalukettu, which translates as “four corners”: a rectangular structure of jackfruit wood and teak, opening on to a roofless central courtyard called a nadumuttam, with four blocks named for the directions they faced. These were not just houses in which women happened to live. They were houses designed around the female body: its cycles, labour, grief, desire and sound.

The buildings were drawn and built by male master carpenters but the brief was set by women. There is a surviving tharavad 20 minutes from Tholanur, called Kandath. It is now kept as a homestay by its custodian, Sudevan Bhagwaldas, who told me stories over ginger tea before leading me to the purathalams. These are raised, cushioned platforms designed for lounging, sitting diagonally opposite each other across the courtyard. The men gathered on one, the women on the other.

“It has been designed,” Bhagwaldas told me, “so that, acoustically, no word spoken by the women can be heard by the men and vice versa – even if you should shout.” The architecture not only sheltered women’s bodies – it protected their conversations.

The kitchen sat in the north-east. The architect Benny Kuriakose, who has restored several tharavads, told me this was because Kerala’s monsoon winds travel from the south-west, so the kitchen’s hot air would be carried away from the house. The women’s bedrooms, on the western side, were spared the kitchen heat. Off them lay smaller rooms: one for childbirth, another for menstruation. A menstruating girl could rest in this room. Her mother may have given birth to her in the other.

In a tharavad that Kuriakose conserved as part of the Muziris Heritage Project, those rooms appear on the architectural plan. A room on the ground floor is labelled: “Corridor with rooms for menstruating women and pregnant ladies.” I have been thinking about that corridor a lot. While researching Herlands, I encountered many examples of women creating systems of care, inheritance and mutual support. What struck me about the tharavad was that those values were embedded not only in social rules but in the architecture itself.

In much of south Asia, the “period hut” has been an instrument of exile. The Hindu practice of chaupadi treats menstruating women as polluted. But some of my relatives insist Palayil told a different story. There, they remembered the period room as a room of rest. A menstruating woman was catered to by other women in the house. She was excused from chores. She was not unclean. She was not exiled. Her body was anticipated, accommodated, given a room of its own.

I have only one photograph of my great-grandmother and she is movie-star beautiful. In Tholanur, the neighbours remembered her beauty, though they told me that even she was outshone by her mother, Palayil Kalyani. She held the keys to the main gate and to the storage room where the jewellery was kept. Her name was on Palayil’s deeds. Her blessing was needed before any business deal, marriage or naming.

Before the first world war, Kalyani arranged for the dried coconut-leaf roof to be replaced with clay tiles, modernising the structure that sheltered her line. This was a house for all women related to Kalyani: widows, single women, cousins, the child-free, new mothers. The architecture protected them all. Kalyani insisted the daughters of Palayil should always live in a safe and secure home. That insistence – that we were protected, financially solvent, not in need of rescue – was drilled into me by my grandmother and mother, who heard it from theirs.

Several Nair communities practised a form of union called sambadhanam, from the Sanskrit sama, equal, and bandham, union, a sexual and relaxed alliance between a man and a woman that could be dissolved at the request of either party. A woman did not move into her husband’s home. He came to hers, and he could be asked to leave.

An arrangement like that needed a house to match. A corridor ran around the outside of the house, the chuttu veranda, lit at night by brass lamps. I have been told it was designed in part as a discreet route for a conjugal visit. The practice ended in the 1800s. But the architecture remembers the possibility.

Another thing it remembered was lineage: a lineage for women. “The birth of a girl child was more prized than a male child because of the role a woman has in physically carrying the progeny,” the Kerala gender academic Lekha NB told me. “This ensured the continuation of the tharavad legacy.” A girl arrived to the ringing of bells. Her body was the architecture’s reason for being.

I do not want to romanticise a system I am descended from but did not live inside. The architecture was generous, yet it was selective. Tharavads were caste structures. While Nair women, mostly literate, read in the courtyard, lower-caste women laboured in the fields outside, often under semi-bonded conditions. My father’s family is of a lower caste; his female relatives would not have been welcomed inside Palayil. A house for women’s bodies, yes, but not for all women.

The system ended in the early 20th century, codified out of existence by laws that dismantled female inheritance and made sambadhanam illegal. Palayil Kalyani built a house for her daughters. The walls fell. But the lesson remained: keep your shelter, keep your independence, keep the key.

Herlands by Megha Mohan is published by Penguin. To support the Guardian, buy your copy from guardianbookshop.com. Delivery charges may apply.