A new development application proposes a seven-storey commercial office space above two existing heritage buildings in Sydney.

Designed by FJMT, the addition will ‘float’ over a former substation and warehouse at 183-185 Clarence Street. The architects have described this design approach as “an alternative paradigm to the conventional extension approach to heritage buildings”. In other words, an ‘anti-extension’.

The proposed seven-storey addition for 183-185 Clarence Street

The proposal also seeks to “reinvigorate [the] two vacant and deteriorating heritage buildings whilst retaining and protecting their key heritage elements”. The two buildings above which the new design will sit are the Electrical Substation at 183 Clarence Street, designed by R H Broderick in 1925 as an example of the inter-war stripped classical style; and the former Shelley warehouse at 185 Clarence Street, designed by Arthur Pritchard in 1909 in the Federation Warehouse style.

According to the current proposal, the Electrical Substation’s Machine Hall will be repurposed for a range of cultural and selected commercial uses. On the other hand, the warehouse will accommodate the entrance and lift core to the proposed commercial office.  

The proposed redevelopment of the Electrical Substation's Machine Hall 

But the proposal’s key design feature is the new ‘floating’ addition. The materiality and detailing of this structure is in strong contrast to the existing heritage façades. The extension is steel-framed with concrete floors and exposed services. The addition is wrapped in a high-performance, double curved glass façade.

Described as a “good neighbour”, the proposed building “has very low levels of reflectivity, and its form bends backwards towards its rounded corners to prevent a perception of towering bulk”.

Due to the positioning and composition of the extension, “an opportunity for intermediate terrace spaces between the old and the new” is provided.

The proposed addition is wrapped in a high-performance, double curved glass façade

The proposal will be on exhibition until 3 October 2017.