Backwater

Beyond its role as a sustainable family home, Backwater demonstrates the viability of building on a flood plain, providing simple principles are observed.

About this project

Located on the Broads, Backwater is raised on piles which required to be driven down a full 10 metres into the chalk rock layer. A grillage of galvanised steel ground beams were mounted on these in order to elevate the house sufficiently to accommodate changing water levels. This limited use of concrete, and the reduction in time on site required to form the substructure, allowed the early construction of a dry deck upon which the house’s stick-built timber frame superstructure could be erected. The latter combination of engineered and traditional timber components was selected for the very practical reason that, being located on a secluded promontory, transportation of materials to the site was limited to a narrow access road, with other elements delivered by boat.

Cross laminated timber and panelised systems were discounted because there was no crane access. Most of the timber specified was standard softwood structural material and easily available on short lead times, with additional justification for the use of timber frame construction being its high strength-to-weight ratio, its workability on site and the ease and speed of its assembly. Use of timber also minimised the load on the substructure and was adaptable to complex, bespoke connections within the roofs.

The lightweight pitched roofs of Backwater’s three lowrise, splayed bays are supported on a regular arrangement of timber portal frames, allowing the spaces below to stand as spacious, vaulted volumes.

The highly insulated building shell was designed to deliver exceptional levels of airtightness, with an MHVR system provided to minimise heat loss through ventilation. Again, the lightweight timber construction provided a positive benefit, due to quicker warm-up times that reduce the need for prolonged use of heating systems and their consequent running costs.

The preference for timber construction is also evident on Backwater’s exterior. The side walls and roofs are clad with blackened western red cedar shingles in order to better express the dwelling’s form as an abstracted, folded plane. The front and rear elevations are also shingled, but have been left untreated to allow them to weather naturally and develop a warm, textured appearance.

Layered timber decking projects from the house’s waterside frontage to provide external space that is usable throughout the seasons and to act as a transition from water level up to the elevated ground floor. Beyond its role as a sustainable family home, Backwater demonstrates the viability of building on a flood plain, providing simple principles are observed. Elevating the building on piles is not especially innovative, but it is a practical and a wellproven solution that works. As such, it is an object lesson to developers thinking of building on sites liable to flooding, as is the common-sense use of lightweight timber structures on top.