Architecture

Floods don't wash with this amphibious floating house

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The Formosa amphibious house designed by Baca Architects is nearing completion
The Formosa amphibious house designed by Baca Architects is nearing completion
Formosa is designed to rise by up to 2.5 m (8.2 ft) in the event of a flood
A garden view concept drawing of Formosa
A front-on exterior view concept drawing of Formosa
A context setting concept of Formosa
A diagram showing how Formosa rises in the event of a flood
A diagram showing the normal and flood positions of Formosa
A interior concept drawing of Formosa
The chain-ferry used to transport materials to the Formosa site during construction
A view of the posts used to guide Formosa when it rises
A view from the bedroom of Formosa during construction
A view of the Formosa living room during construction
A view of the Formosa site during construction
The Formosa amphibious house designed by Baca Architects is nearing completion
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Living in an area prone to flooding has historically meant that you need high sockets and deep pockets. Baca Architects, however, has come up with an altogether more ingenious solution. Its "amphibious house," designed to float on floodwater before being gently placed back down, is nearly complete.

The house, called Formosa, is situated 10 m (33 ft) from the River Thames in Buckinghamshire, UK, in an area designated as Flood Zone 3b. Not only is this an area at high risk of flooding, but it is recognized as a functional floodplain where water must be allowed to flow or be stored at times of flooding. As such, any building must both remain operational during times of flooding and not impede the flow or storage of water.

Formosa was granted planning permission in 2012, and is designed to rise by up to 2.5 m (8.2 ft) in the event of a flood. Baca says that such a level would is well above the current and future predicted levels for the area and company director Richard Coutts told Gizmag at the time of planning approval that such a flood would be "a one in one-hundred year event."

Formosa is designed to rise by up to 2.5 m (8.2 ft) in the event of a flood

Baca's other director, Robert Barker, tells Gizmag that, although the house is not the first amphibious one in the world, it is the first amphibious one in the UK. Not only is the site on an island, requiring materials to be transported by chain-ferry, the Environment Agency had also never heard of an amphibious house, meaning a huge amount of work had to be done for Baca to convince the agency of the project's viability.

"Options for the site included either a floating or an elevated property," explains Barker. "A floating property would be in the river course, which was not allowed by the Environment Agency at this location. An elevated building would be set high enough to avoid an extreme flood but almost a story away from the garden. An amphibious house solves these issues by allowing occupants to enjoy their garden, only rising to avoid floods when necessary."

A diagram showing how Formosa rises in the event of a flood

The house is set into a wet dock with retaining walls and a base slab. Four vertical posts, or "dolphins," are used to guide the house upwards in a stable manner when the water level rises. The structure itself is designed with a concrete base and enough ballast to further ensure stability. The facilities in the house use flexible pipes meaning that everything should remain operational both during and after any flood. In addition to its ability to float, the house is highly insulated and incorporates a Mechanical Ventilation and Heat Recovery System to keep heating requirements down to a minimum.

"The cost of rising insurance premiums for buildings located within flood-prone areas has created demand from the construction industry to innovate and evolve building technologies," Barker tells Gizmag when asked about the potential of the technology. "Amphibious construction to date has only been used in small buildings but it has the potential to overcome flood risk on a much larger scale by creating whole floating platforms or even floating villages and towns. This could provide a cost effective solution to regenerating or preserving important sites where relocating residents and communities would have dire social and economic consequences."

Formosa is due for completion next month.

Source: Baca Architects

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9 comments
Facebook User
Saw it on Grand Designs. Looks like an awful oversized garden shed. Not worth anything near the money he spent doing it. Even with the river view, which you can get much cheaper.
Bob Shock
Isn't flood water often contaminated with raw sewage? Seems like you would have a nasty cleanup on your hands afterwards or some awful smells coming from the basement for a while.
liui
"the Environment Agency had also never heard of an amphibious house"....hmmm, doesn't a houseboat count?
ivan4
This is nothing really new, apart from being totally on land. Back in Victorian times there were boat houses, with accommodation for staff that were built to rise and fall with the tide. Some of them were still in existence in the late 40s and early 50s
John Banister
It's very nice that innovation made it past the permitting project. My parents live in a town that's in a floodplain, and a single position houseboat wouldn't meet the "ground floor must be above this mark" criterion placed on all new construction. I think the biggest problem for the owners of a house like this is going to be making sure that, in the years between floods, there's no oxidation related stiffening of the often flexible materials that seal the water out and keep the drains connected to the city.
Ianspeed
Yep, saw this on Grand Designs the other night....£250,000 just for the concrete waterproof basement...So environmentally unfriendly, also as noted on Grand Designs, no thought had gone in to the rest of the build, looks like a bodged tin shed. Hmmm what type of boat could I have bought that money? Guess they will be probably be limited by weight distribution to stop the dolphins (guiding girders) from getting uneven loads and jamming...
Tom S.
Great solution. I assume their is an air space between the bottom of the pit and the hull bottom of the lower floor so it will sit on points. Thus the water can be pumped out and filtered water used to clean out the small amount of dirt. I did not see any feature to insure mostly water went into the pit. In floods lots of floating stuff and mud get carried by the swift water. Note the course of a river change during floods. A screen surfaced diaphragm with floats to keep it from folding under is needed to keep the pit clear.
pmshah
You go to Srinagar in Kashmir and you see a whole lot of full fledged house boats !
@Tom S.
They would have to plan for conventional sump pumps capable of also handling some amount of solids and water jet system to wash out the entire underside.
@Ianspeed
They would have to borrow some idea either from Citroen of "Kalashnikov" to keep the house from jamming and balanced !
Slowburn
I'll just build the house to keep the water out.