To comply with development’s financial viability requirements, the Client’s brief was to add to the heritage buildings a new 20 storey building. However, key specified constraints prohibited any change to the heritage building sections, or extra permanent loading on the heritage structures.  The economic potential of the site was achieved by an innovative architectural solution being realised by a unique structural engineering concept. The feature of this concept was the design and construction of the top 10 levels of the 20 storey office building cantilevering above the heritage buildings.  An efficient, innovative steel framed structure of the tower allowed the 1916 and 1933 heritage buildings to be free of any structural intervention or additional permanent loads. The solution reduced the complexity of the initial design scheme and saved over 400 tonne of structural steel.  The project became financial viable through the use of structural steel and the innovative project design and construct team.