Shortlisted: Design & Technical Award
‘An amphibious house is a building that rests on the ground on fixed foundations but whenever a flood occurs, rises up in its dock and floats there buoyed by the floodwater.’
This is the UK’s first amphibious house, a can-float amphibious building. What can one take away from this research? Possibly a combination of wisdom, wit and pleasure.
At the most basic level it is the wisdom to understand that flood risk is a key determinant in building design. If your site is at risk from flooding then engage with this fundamental constraint from the beginning or risk serious abortive work.
Flooding can occur from a number of sources – river flooding (fluvial) as is the case of the Amphibious House, and surface water flooding (pluvial) which tends to be more common in urban areas. Flood risk is commonly considered as a combination of probability (likelihood of exposure to flooding) and consequence (the vulnerability of the receptor to being flooded). Reducing flood risk requires a combination of both factors.
Flood protection to an individual property may be required where it is not possible to reduce to reduce flood risk through planning or landscape measures alone. Several building types and flood-proofing can be used to protect a property, including elevated, flood resistant (dry proof), flood resistant (wet proof), can-float (buoyant base), amphibious (buoyant habitable base) and floating houses.
Turning a constraint into an opportunity is what architects do best. At the site of our Amphibious House in Buckinghamshire covenants would not allow us to raise the ridge line, and the Environment Agency’s predicted flood levels were onerous. Elevating the property above flood level would have allowed us a build zone of only 1.5 floors. This amphibious house enabled us to create three floors: consisting of a habitable displacement basement, a ground floor, only a few steps up from the garden and a mezzanine floor within the roof void. All would be buoyed by floodwaters using the Archimedes displacement principle to keep its occupants dry. The same principal that floats a rubber duck in the bath!
Aquatecture promotes building techniques that are co-designed with the landscape and waterscape which surrounds and supports them; different techniques aim to anticipate, avoid or protect from floodwater as required. For this house we designed an ‘intuitive landscape’ that was hydrologically linked to the river. Conceived as a series of plateaus or ‘flood cells’, staggered in section, the landscape fuses art and technology and acts as an early warning system. As the Thames rises and inundates a number of predetermined cells, the building is engineered to float and will rise with the water. When the water recedes it will drop back gently, to a predetermined level.
Advancing amphibious methods has revealed an absence of statutory and approved construction techniques for floating buildings and displacement structures. This has in turn created uncertainty for funders, warrantors and mortgage providers. Additionally, basic resilience measures (to flooding, climate change etc) are also absent from the Building Regulations. Thus for the moment this technology is unfortunately restricted to those who show initiative and are able to self-fund.
Floating and amphibious developments offer a credible solution – to improve existing communities in the floodplain, to re-vitalise post-industrial waterscapes or to create vibrant waterfronts for emerging cities. What we need now is for regulation to catch up with technology – to give funders confidence and finally to unlock these exciting new possibilities.
Richard Coutts, Baca Architects, and Robert Barker, Forrest Mews (formerly Baca Architects)