Project Overview
The UK’s first amphibious house, designed by Baca Architects, has been built on an island on the banks of the River Thames. 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.
Using the latest technology, the property is a major breakthrough for British architects and engineers who have been searching for many years for a solution to mitigate the risk - and damage - of water ingress to homes in flood-prone areas.
The truly unique 225sqm house – located just 10m from the river’s edge - replaces a dilapidated bungalow with a contemporary family home that has been carefully designed to respond to the uncertainties of the future climate.
While the house will be a modern, highly insulated, low energy building, including large high-performance windows, the architects have ensured that it is also sympathetic to the locality; a scenic spot with very strict planning guidelines. The property has a pitched roof to complement neighbouring homes and an overall footprint that is no larger than the old demolished property.
Project Commissioner
Project Creator
Team
Richard Coutts
Robert Barker
Rob Pattison
Riccardo Pellizzon
Project Brief
The client wanted a generous home on the river but within walking distance of the town centre. When they found a property on the edge of the River Thames it was too small for their needs but in a beautiful location. The previous house, built before 1945, is raised on timber posts to protect it from flooding and clad in timber boarding.
Local planning restrictions meant that the building could not be significantly increased in height and the change in flood-risk policy meant that the building could not be significantly extended. And, if it were to be replaced with a new dwelling, the floor level would need to be raised to approximately 2m above the ground level.
The solution developed by Baca Architects was to create a building that would sit in the ground but in a way that did not increase the flood risk by designing a property that would float during a flood – an Amphibious House. The house rests on a concrete hull creating a ‘free-floating pontoon’, set between four ‘dolphins’, or permanent vertical guideposts. The building can rise and fall over 2.5m well in excess of the worst predicted flood level allowing for climate change.
Project Need
The site is located on an island in the floodplain of the River Thames in Flood Zone 3b, classified as the Functional Floodplain. The island is already developed with a number of residential properties and local council records indicate that there has been a property on the site since at least 1926.
As flood risk was one of the key site constraints, the Environment Agency (EA) was approached at the outset of the design process to discuss various design approaches. Three construction methods were presented to the agency - flood resilient, amphibious and floating design – with the EA indicating that either flood resilient or an amphibious dwelling would be appropriate.
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. This form of construction is one of several technologies that Baca Architects is using to resolve flood risk in a number of areas in the UK and the Netherlands.
Design Challenge
The biggest challenges were the planning / environment agency consents, and the access to the island.
The local planning authority and the environment agency were unfamiliar with an amphibious house so we had to provide a lot of supporting documentation to demonstrate that it would work and was the right solution.
Prior to this project there had never been an amphibious house that had secured planning in England. It wasn't covered by building regulations and is also located in a conservation area so during the course of the project we have had to go through numerous negotiations with all the various statutory bodies to set a responsible president for other houses that may well follow.
Given that the site is on an island with no road access this meant that the only way to access the site was by river. This meant a novel construction, involving negotiating field hire and using a chain ferry to bring goods across from the other side of the river. This meant that normal design approaches had to be adjusted to suit the size and weight limits of the ferry.
Sustainability
The house is both sustainable and adapted to climate change. The house is a modern, highly insulated, low energy building. It is also amphibious, meaning that it can cope with significant flood levels and with uncertainty over future flood levels.
High performance insulation and double-glazing reduces the heating demand of the house, which also incorporates a heat recovery ventilation system to further reduce energy demand. External louvres form a feature of the façade, helping to shade the building from the southern sun.
The riverside garden includes a number of terraces stepping from the house down to the water’s edge. These terraces are set at different levels that will incrementally flood when the river rises from its banks; a key part of the practice’s ‘intuitive landscape’ philosophy, that aims to shape spaces around settlements so that they can flood in a predetermined way. This allows residents to be more conscious of their natural environment and in turn raise their awareness to flood risk. The building is set back from the river to create an 8m buffer zone as required by planning, a law which provides an ecological continuity along the river and protects the character of the waterfront.
Architecture - Residential - Constructed
This award celebrates the design process and product of planning, designing and constructing form, space and ambience that reflect functional, technical, social, and aesthetic considerations. Consideration given for material selection, technology, light and shadow.
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