Greenland Centre is a residential tower development, located in Sydney’s CBD. The 67-storey tower is designed to be Sydney’s tallest residential building.

BVN was selected from a field of six international architects to design the tower through a City of Sydney Design Excellence Competition.

The retention of the existing building constructed in the 1960s enabled Greenland to demonstrate an innovative approach to sustainable urban development by using the extant steel frame as the basis for an enlarged structure; to demonstrate that an office building can readily be converted to an apartment building and by a collaboration with the City of Sydney provide a range of public performance, recording and studio spaces for the citizens of Sydney.

The opportunity that the use of the existing structure- the heritage-listed Water Board building - is complicated by the need to provide external access to apartments in the new tower on its western edge. The existing tower is built to the boundary on the west but is set back from the boundary to the east. Therefore, to the west there is no permeability for the upper apartments for its entire height due to fire code requirements.

The solution to this conundrum is to slide the upper tower to the east enabling all-round access for all the apartments. This is structurally achieved by the insertion of a large transfer truss between the lower and upper towers. The large view composition of the building therefore is one of a new tower, transferring diagonally through the truss to the lower tower’s different structural grid.

The development includes 481 units, a Council-administered creative hub, retail spaces and a new public realm network.

This visual dynamic results in a building that not only reveals an interesting and dynamic composition on the skyline but reveals the narrative of a new tower planted upon an existing building – a sustainable outcome that prevented the waste, time, inconvenience and discarded energy required to demolish the lower tower and build a completely new structure.

The building is skinned with a modulating angled glass facade to create wintergardens. Without this added layer, the wind levels at height would make an outdoor balcony unusable. The unique glass-fronted ‘Sydney balconies’ conjure the idea of the quintessential verandah that can be used year round.

The Australian verandah has always been the “outdoor room” of Australian residential architecture and has articulated the laconic lifestyle of Australian domesticity.

The Greenland Centre upper tower’s lowest floor on level 26 is about the level where it becomes difficult to properly utilize a balcony a tower. The challenge was to liberate the unused balcony spaces on towers to make them usable as much as possible by countering the strong wind buffering and pressure issues usually associated with tall tower balconies.

In collaboration with the City of Sydney, BVN and Arup developed a proposition that allows a partial enclosure solution which enables the floor area to escape calculation for the City; and for the occupant will provide a space on the outside of the tower that will be useable for most of the year.

The City’s requirements were that there be 25 percent of the surface area of the enclosure open to the air; our requirements were to provide a solution that created a whole new spatial experience in high residential towers.

The engineering design and the architectural design created the “Sydney Verandah” – a space that is defined by a single plate of glass suspended from above and propped out at floor level to spatially create a visually unencumbered glass wall enabling a sense of safe enclosure without the need for a handrail. This effectively creates a windshield and allows the air to travel across the glass surface dealing with the effect of the horizontal buffering and pressure.

The result is a space that seamlessly opens the sitting rooms onto the verandah space and connects the interior of the apartment directly to the vastness of the external space without the visual hindrance of a handrail. The majority of the verandahs face north ensuring that the space will be warmed by the winter sun; and the apartments can effectively be left open to the fresh air all day.

By the use of timber floors and soffits, an external room is created that resonates with the characteristics of a truly unique Australian “place” within the ubiquitous international typology of the tall apartment tower.

Greenland Centre is expected to be complete by late 2020.