In 1905, a deadly earthquake rocked the landscape of Himachal Pradesh, an Indian state in the western Himalayas. Sturdy-looking concrete constructions toppled like houses of cards. The only surviving structures were in towns where the residents had used an ancient, traditional Himalayan building technique known as kath kuni.
On a warm Tuesday afternoon, I was headed towards one of them: Naggar Castle, which was built more than 500 years ago as the seat of the region's powerful Kullu kings, and which remained standing, unscathed, after that calamity.
Officers from the Geological Survey of India were amazed by the lack of seismic damage to the castle and other kath kuni homes in the earthquake's radius. "This, at first sight, appeared unnatural on account of the apparently rather top-heavy construction of the houses… until one came to realise the natural resisting power of their timber-bonded walls," they wrote.
The castle is one of the most exquisite remaining examples of the building style, but kath kuni houses have been constructed in this region for thousands of years. The design is recognisable by its layered interlocking of deodar wood (a type of Himalayan cedar) with locally sourced stone, without the use of mortar. Naggar Castle is now a hotel and tourist attraction, but its rustic walls – flat-stacked grey stones alternating with earth-toned planks of wood – are proof that some things are timeless.
As a design, kath kuni is ingenious. "Deodar wood and stone create a spectacular balance and composition together," said Rahul Bhushan, architect and founder at NORTH, a Naggar-based architecture and design studio working to preserve the building technique through construction projects, workshops, artist residencies and homestays. "Stone gives weight to the structure, resulting in a low centre of gravity, and wood holds the structure together, thanks to its flexibility."
The technique is perfectly suited to the Himalayas, one of the most seismically active zones in the world (Credit: Tarang Mohnot)
The technique is perfectly suited to the Himalayas, one of the most seismically active zones in the world. Doors and windows are built small and have heavy wooden frames to lessen the stress on the openings during an earthquake. Plus, the buildings have fewer of these openings to help transfer inertial forces to the ground. On top of it all, thick slate roofs hold the whole edifice firmly in place.
The words "kath kuni" are derived from Sanskrit, translating to "wooden corner". "This describes the essence of the building style," said Tedhi Singh, one of the few remaining mistris (masons) in Chehni – the only village in Himachal Pradesh where the houses are all kath kuni, as opposed to other villages where newer concrete houses are more common. "Take a look at the corners of any kath kuni building and you'll clearly see beams of wood interlocked together. Gaps between these layers are packed with small stones, hay and rubble. This system of intricate interlocking makes kath kuni structures remarkably flexible, allowing walls to move and adjust in case of a seismic event."
Singh added that kath kuni structures have double-layered walls that act as insulators, keeping the space warm in the frigid winter months and cool in the summers. Trenches in the ground and raised beds of stone blocks strengthen the superstructure, while keeping water and snow from seeping in.
Naggar Castle is one of the most exquisite remaining examples of kath kuni (Credit: Tarang Mohnot)
In addition to these quake-proof qualities, kath kuni architecture is also well-adapted to the region's agrarian and communitarian style of living. Generally, the ground floor is reserved for livestock. Upper storeys are used as living quarters since they're a lot warmer, thanks to the sunlight and the rising body heat of livestock from below.
"I can't imagine living in a concrete structure… they simply don't fit our lifestyle," said Mohini, who lives with her husband and daughter in a century-old stone-and-wood structure in Chachogi, a tiny village near Naggar. "Kath kuni homes are designed in a way that lets us keep our cattle loose in the open space on the bottom storey and move them inside at the time of milking or during harsh weather conditions. They are also generally built in clusters, making it easy for us to share livestock and storage space."
Over time, the building technique has been passed down through generations. However, the tradition is dying as clusters of flat-roofed concrete houses are taking precedence in many villages. Several locals are even concealing their concrete homes with stone tiles and wood-finish wallpapers – desperate attempts to preserve identity as raw materials for kath kuni have become more difficult and expensive to obtain.
As Himachal Pradesh's traditional dwellings became expensive and unfeasible, the concrete industry gathered steam (Credit: Tarang Mohnot)
In 1964, the British Empire established the Forest Department in India, leading to a sudden transfer of forest ownership from the locals to the state. This spurred the rampant extraction and commercial use of deodar in present-day Himachal Pradesh. In an attempt to repair the relationship between forests and local forest-dwellers, the Indian government passed the Forest Rights Act in 2006, which entitles each Himachali family to just one tree every 10 years – hardly enough wood to build a house.
"Opposed to kath kuni, concrete looks jarring to the eyes because it's not in sync with the landscape. But it's not like the locals don't want to build wooden houses – they simply lack access to the required resources," said Sonali Gupta, an anthropological archaeologist and the founding director of the Himalayan Institute of Cultural and Heritage Studies.
As Himachal Pradesh's traditional dwellings became expensive and unfeasible, the concrete industry gathered steam. Bricks and cement presented locals with a cheaper and quicker way to build houses. "Kath kuni structures come with higher one-time costs, and people find it hard to shell out those amounts," said Bhushan.
Chehni is the only village in Himachal Pradesh where the houses are all kath kuni (Credit: Tarang Mohnot)
Along with the fall in the demand for kath kuni structures, there's been a steady decline in the number of mistris who specialise in the art, coupled with a growing belief that concrete structures are more durable. However, Himachal Pradesh has undergone scores of earthquakes of magnitude 4.0 and higher in the past 100 years, and during these seismic events, concrete houses proved liable to damage.
Finally, aspects of kath kuni have also become somewhat irrelevant in the context of Himachal's evolving culture and values. "Kath kuni houses have really small doors," said Mohini. "In the old days, people bowed at the entrance, for this also meant bowing before the household deity in reverence. But today, one doesn't want to bend before anyone – not even God."
Mohini is confident that her daughter will live her life in the same house that two generations before her have called home (Credit: Tarang Mohnot)
Despite these challenges, local organisations are trying to find ways to promote and save traditional building methods. For example, NORTH works with its clients to design projects in the kath kuni style and collaborates with local artisans for the construction. They are also investigating whether alternative materials such as bamboo could replace wood to make the kath kuni style more sustainable in the long-term. In addition, Bhushan is experimenting with dhajji dewari, another old Himalayan building technique that uses timber frames and earth infill, and is a lot more cost- and time-effective than kath kuni. And since Himachal Pradesh is a tourism-heavy state, boutique accommodations such as Neeralaya and Firdaus bolster education and appreciation of local architecture by offering tourists the opportunity to stay in kath kuni-style homes, as well as experience regional cooking and activities such as fishing and forest bathing.
"Earthquakes will come and go, but the house will live on"
Even with this revived focus on the old ways, mistri Tedhi Singh worries that once smooth roads connect Chehni to the world, cement will make its way to the village, requiring him to adopt modern-day techniques. "It's quite bittersweet," he said. "The thought of good roads is like a dream but working with bricks and cement just won't be the same."
As for Mohini, she is confident that her daughter will live her life in the same house that two generations before her have called home. "I will teach her how to preserve this house and make her understand that such houses can't be made again... earthquakes will come and go, but the house will live on – take care of it."
Heritage Architecture is a BBC Travel series that explores the world's most interesting and unusual buildings that define a place through aesthetic beauty and inventive ways of adapting to local environments.
---
Join more than three million BBC Travel fans by liking us on Facebook, or follow us on Twitter and Instagram.
If you liked this story, sign up for the weekly bbc.com features newsletter called "The Essential List". A handpicked selection of stories from BBC Future, Culture, Worklife and Travel, delivered to your inbox every Friday.