The brief for STC Foots Cray required new facilities to be provided for offices, laboratories and a microchip production building on a congested site that had been developed expediently over a long period of time. It was important to ensure that neither demolition nor building operations disrupt the continuity of existing sensitive manufacturing processes.

Located adjacent green belt countryside but also near to housing and a mix of commercial and industrial users, the project encompassed master planning proposals and phased building operations including the rationalisation of underground services, security facilities, parking and vehicular circulation to meet both the short and long term needs of the company.

Buildings and landscaping were designed to alleviate problems of flood conditions and required the diversion of the river Cray, which bisects the site.

The appearance of the buildings is intended to be expressive of the high technology processes and activities within, create an image of business-like efficiency and provide an attractive frontage to the Maidstone Road.


An important element of the redevelopment of the STC site at Foots Cray is the microchip production facility known as the Wafer Fab Building. Silicon wafers undergo production processes of a breathtakingly microscopic scale, demanding a working environment in which absolute cleanliness and elimination of vibration are demanding design requirements.

Production involves photochemical processes, diffusion and ion implantation to build up the microscopic circuits on the silicon wafer. The cleanroom, designed to Class 10 and Class 1 air purity, is an enclosure structurally isolated from the surrounding plant which provides the vertical lamina flow air conditioning. A long span roof structure carries the load of overhead services and ensures a column free production area allowing maximum flexibility. The cleanroom is designed with modular ceiling, partition and perforated raised floor systems to allow reconfiguration of the production area. Piped services rise from the plant room below and distribute within dedicated service ‘corridors’ which are fully accessible from outside the clean production area.

The design aimed to provide a simple, easily maintained, economic envelope that would also project an image appropriate to the technology contained and the nature of the end product. The building features glazed end walls, which add scale and interest to the exterior and provide a visual link between inside and outside space.