Given that the project was ostensibly a self-build, the main objective was to keep it as simple and economic as possible.
Poor subsoil conditions, exacerbated by the proximity of both existing and removed trees, with the resulting potential for significant ground movements, meant that a piling solution was adopted. 300mm-diameter bored, cast in situ piles with individual pile caps incorporating heave protection were used.
The piled foundations, together with the requirement for a floating roof plane, led to the development of a lightweight steel-framed superstructure, which also offered the advantages of speed and accuracy of construction. Due to the continuous clerestory glazing and lack of window free elevations, it was not possible to use vertical bracing to provide stability. A three-dimensional steel sway-frame was therefore used for the superstructure, to provide lateral and longitudinal stability against wind loads.
The steel frame consisted of pairs of channels bolted on either side of 100mm SHS columns with rigid connections. The columns were linked rigidly on the long elevations, and positioned inboard of the external envelope, to avoid cold bridging. 175mm timber joists were designed to span between the steel beams, to form the deck at each level, giving a minimal floor depth.
The ground floor was raised significantly above the external ground level, giving a useful undercroft area for storage and courtyard ventilation, as well as allowing the building visually to float over the ground plane. The beams and stub columns at ground floor level down to pile cap level were also rigidly connected, to allow the pile caps to be linked without the need for a layer of ground beams.
This significantly reduced the cost of the groundworks.
Cantilevered Masonite timber studs were used externally to provide the support for the clay tile cladding system. These studs were fixed at ground and first-floor levels and cantilevered up to the sill of the high level glazing. In this way, uninterrupted clerestory glazing could be achieved around the whole perimeter of the building. The studs also reduced cold bridging and so helped achieve the required high U-value of the walls.
The glazed courtyard structure comprised steel box-sections tied to the main building and provided support to the glazing as well as stability to the flank wall. These members were connected to a steel channel, forming the gutter that naturally sloped due to the tapering plan, the channels being connected to the brick piers with adjustable brackets.