Engineer builds low-cost floating house in Bihar to withstand monsoon floods

Engineer Prashant Kumar has constructed a three-room house beside the Ganga in Bihar that floats when floodwaters rise, then settles back on its foundation as the water recedes. The design was motivated by the annual displacement and damage caused by monsoon flooding in the region.

The structure uses materials sourced within a 10-kilometre radius, including recycled pipes and eco-friendly bricks made from cow dung, lime, jaggery and rice husk. It also incorporates solar panels for electricity, a dry toilet system that converts waste into compost, and surrounding green lawns.

Kumar reports that the prototype was built for approximately Rs 6 lakh (about US$7,200). The house is designed to remain cool in summer, warm in winter, and buoyant during floods, functioning as a carbon-negative dwelling.

The engineer is now working to reduce the construction cost to around Rs 1.5 lakh per unit to make the model more accessible for vulnerable communities. His longer-term goal is to develop an entire floating village that can withstand floods while remaining sustainable and self-reliant.

The project addresses a recurring climate challenge in Bihar, where rising rivers regularly cut off neighbourhoods and force families to evacuate. By designing a home that works with flood cycles rather than resisting them, the approach offers a potential adaptation strategy for flood-prone areas.

Research limitations include the absence of independent structural testing data, long-term durability assessments, or verification of the carbon-negative claim. The cost figures and performance descriptions are based on the builder's own reporting.

No government agency or external engineering body has been cited as having certified the design. The concept remains at the prototype stage, with the floating village vision still in the planning phase.