Bamboo frame holding two blue plastic barrels, joined with green nylon straps, screws and jute rope

Kutcha

Buoyant housing toolkit

Year: 2025
Place: Bangladesh
Context: Final solo project, Innovation Design Engineering, Royal College of Art and Imperial College London
Role: Research, design, structure, prototyping

53,582: homes destroyed in one 2024 monsoon
< $45: monthly household income
Any height: of flood. The house needs no prediction

Stilt houses were designed for a 1 metre flood. In 2024 the water reached 1.56 metres. The families who lost everything earn less than $45 a month.

01The flood

One monsoon season in 2024 destroyed 53,582 homes in Bangladesh and damaged 153,738 more. The families who lost everything earn less than $45 a month.

Map of Bangladesh shaded by flood type, with millions affected per region — Where the water went in 2024.

Diagram of linked causes leading to the climate crisis — Why the losses were so large.

Stilt houses there are built for a 1 metre flood. In 2024 the water reached 1.56 metres. Flood peaks no longer follow the historical record, so any house built to a fixed height is a guess.

Chart of flood peaks from 1987 to 2024 beside a stilt house drawing with the 2024 water line above its design height — Thirty-seven years of flood peaks, and the stilt house they were designed around.

02The idea

Stop guessing the height. A house that floats rises with whatever comes and settles back onto its footings when the water goes.

Section. The water passes the height a stilt house is built for and stops at the 2024 flood level. The house lifts on its raft along two guide posts and settles back onto its footings.

Two sections of the house: on the ground, and lifted on its raft by flood water — On the ground, and lifted by the flood.

Render of a small pitched-roof house floating on flood water in the rain — The house afloat.

03Who I asked

Apurba Swati Mehboob UN Development Programme, Bangladesh
AA K M Zahirul Alam Shelter Cluster Coordinator, IFRC, Bangladesh
Wouter Buytaert Professor of Hydrology and Water Resources, Imperial College London
Asim Waqif Architect and bamboo artist, India
Nishchal Pradhan Head of Innovation, Base Bahay Foundation
Ruhul Abdin Architectural designer, Bangladesh. Through him I reached carpenters and masons in flood-affected districts, who checked the material list against what is available, affordable and buildable there.

Flash flood peaks in Bangladesh are non-stationary. You can’t design to a historical average any more.
Wouter Buytaert

Bamboo is only as strong as how it’s cut, cured, and joined. Get those three right and you don’t need steel.
Asim Waqif

04How it is built

A bamboo frame sits on a raft of HDPE barrels. Guide posts set in concrete footings keep it in place as it rises. The walls are bahareque with cement plaster. A planted earth berm slows the water before it arrives.

Exploded drawing of the house labelled roof, bamboo truss, bahareque shear walls, cement plaster, raft, guiding rail, bamboo columns, flood berm — Structural system, labelled from the corrugated sheet roof down to the flood berm and vegetation.

Dimensioned section drawing of the house, its footings and the earth berm — Section, in millimetres. Footings 2 metres down; berm 1 metre high, 7 metres wide.

Bamboo: Frame, truss and columns. Carbon negative and grown locally
HDPE barrels: The raft. Cheap and easy to find locally
Reinforced concrete: Footings only. Anchors the guide posts and takes horizontal load
Nylon strap: Lashing. Strong and easy to find
Screws and bolts: Joinery. Strong, and easy to replace
Jute rope: Lashing. Sustainable and easy to find
Earth berm: Planted, 1 metre high and 7 metres wide, to slow the water before it reaches the house

Six material cards: bamboo, HDPE barrels, RCC, nylon strap, screws and bolts, jute rope — Each material, and why.

Bar chart of embodied carbon for three ways of building the house — Embodied carbon per 32 square metre house.

The same house in brick and reinforced concrete is carbon positive. Kutcha, in bamboo with concrete footings, comes out at −421 kgCO₂e.

05What failed

The first rafts were lashed with jute rope alone, and tested on the Thames foreshore. They failed. After talking it through with Asim Waqif and Nishchal Pradhan, the joints changed to nylon strap and screws. That is the raft at the top of this page.

Six photos of bamboo and barrel prototypes, on a floor, a river bank and in the water, linked by arrows — From one barrel and jute to two barrels, strap and screws.

Bamboo raft with two blue barrels joined by green straps and screws — The final raft.

Bamboo stick model of the house frame and raft on a cork base — Model of the frame on its raft.

06What it became

Not one house but a toolkit, so families can build their own with local carpenters and masons.

Diagram of the toolkit's three parts feeding into community training — Manual, structural calculator, 3D model, and training for the people who build.

Toolkit: Construction manual, Excel structural calculator, detailed 3D model, training framework for local contractors and masons
Prototypes: Ten
Materials: Bamboo, HDPE barrels, reinforced concrete footings, nylon strap, screws and bolts, jute rope
Embodied carbon: −421 kgCO₂e per 32 square metre house
Shown: Royal College of Art and Imperial College London show, 2025
Recognition: Shortlisted, Prototypes for Humanity, Dubai, 2025
Tools: Rhino, AutoCAD, Enscape

Exhibition stand with a bamboo and barrel raft, a model of the house and framed prints — The stand at the Royal College of Art and Imperial College London show.

Printed construction manual and project cards lying on the exhibition stand — Manual 1, Floating Foundation System, with the model on the stand.