The existing buildings comprised several structural forms. The Electric Press building itself was originally timber floors and beams supported on cast-iron columns. These had been strengthened by the introduction of a grillage of steel beams which reduced both floor and beam spans.
Stansfeld Chambers comprised a group of very different buildings, including domestic-scale structures such as the 'Georgian House' which had timber floors supported on brick walls. South Stansfeld Chambers had a mixture of load-bearing masonry and cast-iron columns supporting timber floors. East Stansfeld Chambers had a concrete-encased steel frame and concrete floors. The existing structures were carefully surveyed to assess condition and strength. Where necessary, repairs were made using contemporary techniques wherever possible. The floors were strengthened in several ways, including the replacement of members, flitching of timber beams and the introduction of new columns. North Stansfeld Chambers was to become the new theatre entrance and, as such, major changes to floor levels were necessary. It was determined that the most effective way to achieve this was to maintain the existing walls but replace the entire internal structure with a new steel frame and concrete floor. The new theatre auditorium was a new steel frame construction with concrete floors and a roof-top plantroom. The building obviously had stringent acoustic requirements and the transfer of noise from the plantroom through the structure into the auditorium was a major concern. To overcome this potential problem, the plantroom beams were supported on acoustic bearing pads and were then hung from a series of lattice girders spanning over the auditorium.
The upper storeys of the western elevation projected about 2m over the historic building line in order to provide the space required. This was achieved by cantilevering the auditorium lattice girders over the western columns to support hangers carrying the floors and external wall.