Onyx House

Onyx House is an extensive retrofit of a run down industrial warehouse in Hayle, Cornwall. Transforming it from a dilapidated space into a modern office for a holiday lettings company.

KAST designed Sapphire House, a timber framed, shingle clad new-build office for the same client on a nearby plot, however, here, the brief was to re-use the high embodied carbon concrete slab and steel frame, wrapping the existing structure in a new well insulated and air-tight envelope to create a comfortable, low energy building with a series of open plan office spaces and meeting areas for the growing business. The main building footprint is largely the same, now clad in a black profiled metal sheet reflective of its former industrial use, with the new elements, extensions forming an entrance lobby to the front and additional accommodation at the back, clad in timber to differentiate them from the original structure.

Internally the office space is arranged around a central stair and lift core, with ancillary rooms positioned off to one side and a double height office area to the other. To the rear of the office is a communal kitchen and dining area for staff. Internally the steel frame structure and services are left exposed, the frame and ducting for the new MVHR system have been painted black, resulting in a raw and semi-industrial aesthetic. North facing roof lights flood the space with natural light, while the south facing roof is given over to a full photo-voltaic array to maximise renewable energy production.

Onyx House demonstrates how the careful re-use of existing structures and spaces can still offer distinctive and innovative low carbon solutions.