Built to float: The amphibious house that’s redefining climate-resilient living
The amphibious house known as ‘Swapner Bari’—an affordable and sustainable option—is a perfect example of a climate-resilient home that floats during floods and stays cool in summer as well
What if a house could float like a boat when floodwaters rise, stand firm on the ground during the dry season, and remain cool amidst the searing heat of summer? In the floodplains of Bangladesh—where thousands of homes are washed away year after year, and scorching summers turn houses into ovens—that question is no longer a dream; it now has a prototype.
In recent years, Bangladesh has seen several brilliant climate-responsive architectural solutions, ranging from low-cost bamboo structures to tin-shed houses. These designs have helped communities withstand the increasing losses and damages caused by climate change, particularly in coastal and riverine areas.
Sustainability designer Dr Nandan Mukherjee asked a simple question: what does a dream house look like for the Bangladeshi people? Based on responses from thousands of individuals, he developed a design that not only looks beautiful and represents the Bangladeshi ideal of a 'dream house', but also withstands climate disasters and earthquakes up to magnitude 8.
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"Bamboo houses are very good, but my dream house is not a bamboo house—it's a paka (brick and mortar) house," Nandan said, summarising what he had discovered through his research. Dr Nandan Mukherjee is the Lead for Climate Change Adaptation at the Unesco Centre for Water Law, Policy and Science, University of Dundee.
Located in Uttarkhan, Dhaka, the amphibious house appears at first glance to be an ordinary three-storey building, with its bamboo staircase, airy windows and clay-painted walls. However, concealed beneath its foundations is a buoyant base that enables the entire structure to rise with floodwaters.
Four vertical guideposts positioned at the corners keep the house stable as it floats, preventing it from drifting. Once the waters recede, the house gently settles back onto the ground.
"It's simply Archimedes' principle," explained Nandan Mukherjee. "This house weighs 250 tonnes. Just as ferries are designed using Archimedes' principle, we have applied the same concept with 17 buoyant boxes beneath the structure. These support the full weight of the house, including the floor. The platform can support up to 300 tonnes, providing a 50-tonne buffer to ensure it doesn't fail."
"I guarantee this will float," he added.
Nandan Mukherjee has been involved in climate solution driven architecture in Bangladesh for several years. His motivation for pursuing such work stemmed from a tragic story on the banks of the Teesta River.
When the Teesta swelled without warning following the release of water from the Gajoldoba dam, floodwaters rushed into a riverside village. A young mother, standing on a bamboo macha (a raised platform), as she cooked, suddenly heard a splash.
At that moment, her seven-month-old baby had slipped into the floodwater. She jumped in after him but was unable to save him. Her neighbours accused her of negligence, her husband divorced her, and the grief nearly drove her to madness.
That story left a deep scar on Nandan Mukherjee.
"I was expecting my first child at that time," he said. "It traumatised me so deeply that my psychiatrist told me I had two choices: either wait and let the pain pass, or try to find a solution for people like her."
Nandan chose the latter.
His work began in Shariatpur, a flood-prone district, with a $250,000 grant from Global Resilience Partnership. After 500 community discussions, he designed bamboo "dream houses" that could rise with water, offering safety, food and dignity.
Built in 2017, the prototypes won the UN Risk Award in 2019, praised as eco-friendly and affordable. But the houses were soon destroyed by local sand traders—a setback that only strengthened his resolve to refine the design.
When Nandan and his team returned to the communities and asked again what people imagined as their "dream house," most said they did not want a bamboo hut—they wanted paka bari, concrete homes.
But conventional concrete has a heavy price as it contributes up to 40% of construction-related emissions. Searching for alternatives, Nandan's team turned to history—to the pyramids, built from sandstone that had lasted thousands of years.
The answer came in earth blocks, made from a carefully blended mixture of clay soil, sand, and lime.
Unlike kiln-fired bricks, these earth blocks do not release significant emissions during production, making the houses effectively net-zero from the outset.
However, traditional machinery proved inadequate for producing these blocks. "It requires the pressure of twenty 5-tonne trucks at once. After testing five machines, the sixth finally produced the perfect brick," said Nandan.
"The house is built with low-carbon bricks that are 50% stronger than conventional bricks, while generating 75% less carbon emissions," he said. "A regular brick in the market costs around Tk15, but ours costs just Tk7.5. According to BUET, our bricks are 70% stronger than those on the market. Standard bricks have a compressive strength of 21 megapascals, but ours reach 36 megapascals. Market bricks produce 256 kilograms of carbon emissions per thousand bricks—ours produce only 25 kilograms, as we compress them rather than burn them."
Mohammad Sohel, a worker living in the amphibious house, chuckles as he recalls, "Even on the hottest nights, I need to take a blanket to sleep comfortably." The house's design explains why.
The house's design is a self-sustaining ecosystem. The ground floor, known as the livelihood zone, is dedicated to food and water security.
An integrated aquaponics system raises fish and grows vegetables simultaneously, while poultry can be kept indoors. Rainwater harvesting tanks collect and store up to 17,000 litres, ensuring access to clean drinking water.
The upper floors serve as living spaces and are equipped with natural ventilation channels, locally known as gulguli, which funnel hot air out and help maintain a steady indoor temperature of 26°C throughout the year. A 5 kW solar panel system, supplemented by wind turbines, provides electricity for the house.
The structure allows for ample natural light and airflow. Large windows and gaps between bamboo pillars let sunlight pour in, filling the rooms with honey-coloured light. The central feature is a grand, curling bamboo staircase, positioned as the building's core to allow heat to rise and escape through the middle.
The bamboo is treated with natural salts, making it resistant to termites, rot and fungi, while a resin coating protects it from water damage.
A one-bedroom amphibious house can be built for around Tk 5 lakh, while a four-bedroom version costs approximately Tk 25 lakh.
"It makes the house cheaper per square foot than most tin-shed houses in Bangladesh, and less than half the cost of a conventional brick-and-mortar building," said Nandan. "A concrete frame house costs around Tk3,300 per square foot, a semi-paka house with brick costs Tk2,700, and a tin-shed house costs about Tk2,200. In comparison, our house comes in at just Tk1,500 per square foot."
The prototype was piloted in Bangladesh through a collaboration between the University of Dundee, Resilience Solutions, and Brac University's Centre for Climate Change and Environmental Research (C3ER).
For Bangladesh—one of the world's most climate-vulnerable countries—the amphibious house offers a glimpse of the future. Rising seas, stronger cyclones, and unpredictable floods are expected to displace one in seven people in the coming decades. Against such a backdrop, homes that can float, breathe, and sustain themselves may no longer be luxuries, but necessities.
More than just an innovation, the amphibious house is a dream home—born from tragedy, designed for survival, and built with hope for what lies ahead.
"We've completed the research and developed a full production line—from the bricks to the machinery. Now we're moving towards scaling up. We're building factories and will go into full production from next year," Nandan said, outlining their future plans.
