Five years ago 180 Thomas Street, Haymarket Sydney was a four-storey brick plinth with cumbersome structural columns and a central lift core, not the most exciting building nor the easiest to redevelop.

In 2014 a new 180 Thomas Street opens its doors with an extra nine-storeys of 5 Star Green Star Office As Built V3 rated offices, thanks to Bates Smart Architects and a City of Sydney design excellence competition.

By winning the competition to design the development in 2011, Bates Smart were offered a bonus height and floor space ratio (FSR) by the City of Sydney and responded by cantilevering the entire nine-storey addition six metres beyond the existing podium.

Six mega trusses, each weighing 30 tonnes and measuring 20-metres in length, were fabricated in China and shipped to the site before being placed on top of the old building.

Bates Smart used lightweight steel to cantilever the floorplate which benefitted an increased internal floor area and also provided more flexibility with the existing column grid.

It meant the lifts could be relocated to a vertical glass volume on the exterior of the building with no need for further piling, a major tick for when applying for Green Star credits.

The building sits 45 degrees to the north which afforded Bates Smart the flexibility of designing for either horizontal or vertical shading.  The architects decided to use both, and in doing so created a fa├žade of randomly stacked boxes, each with a different shaped solar shading element.

pre-cast concrete passive solar shading elements reduce glare and thermal load on the podium levels while the double-glazed integrated glazing units are shaded by motorised blinds.

Inside the building, Bates Smart looked at manufacturer’s supply-chains and supplier buy-back arrangements as well as dematerialisation methods to achieve their Green Star credits.

An active chilled beam system is threaded throughout the building and supplies fresh, thermally treated air to the offices. A wintergarden,  digital addressable lighting and a rainwater harvesting system add to the building’s sustainability credentials which now includes a 5-star rating ‘As Built’ from the Green Building Council of Australia and a 6-star office fitout rating.

Interface Continuum Carpet, Desso Palatino Tile, Arper Catifa 53 chairs and Knoll/Formway Be Chairs were chosen by Bates Smart because their manufacturers supply Environmental Product Declarations. The concept of dematerialisation was adopted in selected areas of the interiors by Bates Smart, ceiling tiles were not used in spaces directly above desks and work stations. 

 Bates Smart Director Philip Vivian commented on the project:

"Located diagonally across from the new Frank Gehry UTS building, the design needed a strong presence. The architectural form reinterprets the semi-industrial linear forms of historic Haymarket to create a contemporary building that respects the diverse scale and context of the area.

"The form is articulated into a series of seemingly random, stacked, horizontal volumes of varying heights. Each horizontal layer is expressed by a different solar shading system, creating a layered effect of stacked, linear boxes." 

Images: Bates Smart.