By building on the foundations of an old gasholder, our new factory for David Mellor ensures the surrounding landscape is not disturbed by the new development. The factory is located in the village of Hathersage in Derbyshire. The circular form is created with an external wall of local stone, traditionally detailed but with pre-cast concrete quoins and pad-stones. The wall forms a drum to support a shallow-pitched, radial roof structure of lightweight steel trusses. These in turn support a central conical lantern on a second radial structure. All components – tension rods, trusses and ring beams – are exposed and express their function clearly.

Supporting the roof trusses on the pad stones creates a glazed slot around the building, so that the roof cone appears to ‘float’ freely above the drum. The whole assembly is structurally rigid so that it exerts no lateral force on the supporting stone wall. The roof covering is of traditionally-detailed lead on a stepped deck of prefabricated, insulated plywood boxes, each tapered to fit the radial pattern. Instead of using a gutter, rainwater falls from the eaves into a precast-concrete channel at ground level.

Inside, the factory is column-free and loosely organised around two freestanding enclosures for WCs, plant, and noisy machinery.

Many of the building components, including the plywood boxes and the precast-concrete quoins and padstones, were made on site by Mellor’s workforce.

Hopkins Architects subsequently designed further accommodation for the factory site, including a shop, design museum and café.