Amphibious 'Grand Design' ready to take to the water

17 October 2014

The UK’s first “amphibious” house, on the banks of the River Thames in Marlow was featured on Grand Designs this week and is expected to be habitable for its new owners next month.

The house rests on the ground on fixed foundations but, whenever a flood occurs, rises up in its dock and floats, buoyed by the floodwater.

The property is seen as one option for mitigating flood risk in flood-prone areas.

The 225 sq m house – located just 10m from the river’s edge – replaces a dilapidated bungalow with a contemporary family home. The site is a small island in the picturesque stretch of the Thames through Marlow, Buckinghamshire, which is designated as Flood Zone 3b and a Conservation Area.

It is designed by Baca Architects, a specialist in waterfront architecture and flood-resilient aquatecture, with structural engineering by Techniker.

The property is seen as an option for mitigating flood risk in flood-prone areas

The new house will be a modern, highly insulated, low energy building, which has been designed to cope with up to 2.5m of floodwater, well above the future projected flood levels for the area.

In the garden, terraces set at different levels are designed to flood incrementally to alert the occupants well before the water reaches a threatening level. Following flooding, the demarcated levels also help to manage run-off from the house as flood waters begin to subside as well as reducing siltation of the dock.

The house is a lightweight timber construction which rests on a concrete hull, creating a free-floating pontoon, while the whole house is set between four “dolphins”, permanent vertical guideposts that keep it in place. These guideposts, more often found in marinas, have been integrated with the design and are a striking visible feature on the exterior of the building.

Matthew Wells, director of Techniker, said: “The house is designed as a free-floating pontoon. A lightweight superstructure is supported on a concrete base with sufficient ballast to ensure stability and adequate freeboard. The floating house is secured by four dolphins arranged close up to the sidewalls. The assembly is sited within a wet dock comprising retaining walls and base slab. When flooding occurs the dock fills with water and the house rises accordingly.”

The house is a lightweight timber construction which rests on a concrete hull

Richard Coutts, director of Baca Architects, said; “From the outset of the design process we sought expert advice from the Environment Agency to determine the most appropriate construction model to mitigate the flood risk on this particular section of the river and that would also provide a safe dwelling, sympathetic to its setting and fit for the challenges of the 21st century.”

The amphibious home has apparently cost around 20% to 25% more than a similar sized house, but Coutts says that construction costs are predicted to fall as builders and manufacturers get to grips with flooding and embrace new thinking and technology.      

A key challenge of a moveable house lies in the servicing and utilities. The architect, together with a team including Tecnhiker and hydraulics engineer HR Wallingford, say they have “combined tried and tested technology in an highly innovative way”, but are keen to guard the intellectual property.


It was really interesting to see public and professional responses to this episode of Grand Designs on twitter on Wednesday night.

There's always the carping about clients with highly ambitious plans and (thanks to enthusiastic editing by Channel 4 no doubt) apparently bottomless pockets. However the general feeling seemed to be more 'these people are bonkers, but hats off to them'.

Su Butcher, 17 October 2014

I knew the outcome of this project but not the journey, so really interesting to watch (and read the twitter comments). How did the clients stay so calm??!

Sally Hill, 17 October 2014

I watched this programme and I loved it, from the well out-of-their-depth builders at the start that could not organise a pub crawl in a brewery, to the builders that did take it on and used some brains on it. There were better ways than a hand-cranked pontoon to get the materials across!! But the design was solidly done and thought out. As usual Kevin was Mr Negative rather than supportive and sarcastic and as ever health and safety does not apply to anyone dealing with Kevin and Grand Designs. Its such a joke that we now say in the site inductions, " this is not grand designs and you will abide by safety rules given here" lol

peter weston, 17 October 2014

I really would like to know how they connected the services and sewage.

Neil Shanley, 17 October 2014

Just watched Grand Design again. Like previous comment. . How are services connected ?

Graham Simmons, 29 October 2014

I would be interested to know how Peter Weston can make such assumptions based on a tv show which is obviously scripted. Perhaps he can then explain how the professional builders are 7 1/2 months late, still not finished, and over budget by more than the first builders (who were part of the original design team) asked for on a fixed price contract. I usually find it helps to be in the possession of some facts before posting online.

scott cowie, 4 November 2014

The architect should give prompt reply/solution to the problem raised as this will enable others to accept the concept and may contribute to house flood problems worldwide.

Gursharan Singh C.M.I.I.A., 7 November 2014

Long live the innovators! Now why did those who built the City
of Venice or even those who built Amsterdam not thought of the very same idea!?? It certainly does solve the flooding
problem and has great potential for worldwide application in all flood prone regions!

Mr Jose' Scalabrino MCIOB, 6 January 2015

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