A small island located on the River Thames, in south Buckinghamshire, is home to 15 houses. The houses, which were mostly built before the 1950s, are typically raised about 1 m off the ground on timber piles to protect them from flooding. At the time of construction they were only built high enough to protect them from regular flooding rather than extreme flooding. When the owners of one house on the island plan to be built their home they discovered that the floor level would need to be raised a further 1.4 m above the ground level to cope with the predicted extreme. This would’ve resulted in a house with its ground floor elevated 2.5 m above the ground. The house was also subject to Conservation and Environment Agency rules.The solution was an amphibious house, a building that rests on the ground when conditions are dry, but rises up in its dock and floats during a flood.
The house itself sits in the ground and the floating base is almost invisible from the outside. The ground floor of the house is raised above the ground by less than 1 m rather than by almost 2 m as will be required if it were not amphibious. This approach meant that the 225m² three-bedroom dwelling could be constructed over three floors in the place of a single-storey 90m2 house without significantly increasing the ridge height.The site is located in the middle catchment of the river Thames. The river is wide and navigable and requires a large rainfall before it floods. Flow gauges installed along the river help to provide two more days early warning of a flood. However, when the site does flood it can last for several days.Hydroscapes > A carefully laid out garden acts as a natural flood warning system. Terraces set at different levels are designed to flood incrementally and alert the occupants well before the flood water reaches a threatening level – at Baca Architects, we term this an ‘ intuitive landscape’. The lowest terrace is planted with reeds another with shrubs and plants. The lawn is located a level above and the terrace is located at the highest point, immediately below the living room. The terraced levels improve recovery by providing dry areas as water levels drop and plants help to reduce saltation of the dock.The amphibious house is connected to its utilities via elephant cabling. These flexible service pipes are designed to extend up to 3m, allowing all of the services to remain clean and operational during any flood event. Crucially, this also allows the occupants to return to the property immediately after a flood, maximising the continuity of their daily lives.A float test was conducted during construction when the wet dock was filled with the water and the house elevated half a metre under its own buoyancy. The house was also tested again once the steel frame was complete and the house filled with furniture.Between November 2019 and February 2020, severe winter flooding occurred across the United Kingdom. During this period the River Thames swelled and the owners of the #AmphibiousHouse, as featured on Channel 4’s Grand Design series reported: “the house continues to rise and fall without intervention”.This project has led to much excitement in the industry as it is the first of it’s kind in the UK and has set a precedent for alternative approaches to building in a future of increased rainfall and flood.The Amphibious House has won multiple awards for innovation.
