140 Tabernacle Street is a 6-storey, substantial, Victorian, brick, building located on the (acute) intersection of Tabernacle Street and Paul Street.
The Ground Floor and Basement Levels (now an occupied Restaurant) originally housed a Fire Station and occupied the entire building footprint. There was office accommodation above, but only alongside both Tabernacle Street and Paul Street and so above the existing 1st Floor Level Courtyard Level was a void.
This project was, mainly, to infill this void, at all floors (including at roof space level) in lightweight construction, to create additional office accommodation.
The external walls of the original offices facing into the courtyard were supported at 1st Floor Level on substantial, steelwork, rivetted, plate girders carried by columns and spread footings. Throughout the entire duration of the project the Ground Floor restaurant remained fully operational - and so no strengthening works to the existing columns or their foundations were possible. Thus, the only way to justify the additional load from the infill floors was to locate the new 1st – Roof columns over the existing Basement – 1st columns and to ensure that the additional weight was equivalent to the weight of the 330mm walls removed.
In addition to the main courtyard infill, the project scope included several complex structural modifications:
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New Lift Core: Adaptation of a previously constructed (2009) piled raft foundation and two-storey steel frame to accommodate a new vertical transportation core.
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New Stairwell: Structural alterations to the same 2009 steel frame to support the new stair core.
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New Basement Entrance: Structural interventions to create a new basement access, requiring localized demolition, propping, and new support elements.
This project exemplifies the integration of sensitive structural engineering within a heritage setting, delivering modern functionality while respecting historical context and minimising disruption to ongoing commercial operations.
