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Baca Architects' 'amphibious' house in its waterside setting in Marlow

An ‘amphimbious’ house designed by Baca Architects has been granted planning permission on an island site in the Thames in Marlow, Buckinghamshire. It will replace an existing bungalow on the site which lies in a designated Flood Zone 3b and in a Conservation Area.

View of the house from the Thames

Planning restrictions limited any increase in the building’s height, and flood risk policy did not allow for significant extension to the existing footprint.

The proposed house is set back from the river to create an 8m ecological buffer zone required by planning. A riverside terraced garden is designed to flood incrementally and acts as a flood-warning system.  The lower level terraces will be planted with reeds,  a higher level with flood-resistant shrubs and plants, and above will be the lawn.  This layering of the garden is designed to manage run-off from the house as  water subsides after flooding and reduce siltation of the dock.

The design of the house incorporates guideposts from marina design to create a free-floating pontoon. Techniker structural engineer Matthew Wells explains the floating design: ‘A lightweight  timber superstructure is supported on a concrete base with sufficient ballast to ensure stability and adequate freeboard. The floating house is secured by four dolphins (permanent vertical posts) 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.’

Site section

Site section during flooding

Other features of the design include:

• high performance insulation
• double-glazing
• external blinds
• heat recovery ventilation system
• solar panels.

Interior view of ground level

The house is estimated to cost  20% to 25% more than a  similarly sized conventional house.