Lead Architect: Alec Tzannes
Company Bio: Tzannes is a wide-ranging architectural firm known for their design judgment and attention to detail across varying scales and project types. Their research-based process prioritises the merging of the building, its context, and its functionality in an elegant and understated way.
Location: Barangaroo South, Sydney
Completion Date: 2018
Structural Engineers: Lendlease
Senior Project Manager: Jeremy Tompson
Awards: AIA (NSW) Milo Dunphy Award for Sustainable Architecture (2018)
AIA (NSW) Sir Arthur G. Stephenson Award for Commercial Architecture (2018)
Chicago Athenaeum and the European Centre for Architecture and Design – 2017 International Architecture Award
Australian Timber Design Award (2017)
Australian Timber Design Award (2017) – Excellence Award for Public or Commercial Building
Australian Timber Design Award (2017) – Excellence Award for Sustainability
Australian Timber Design Award (2017) – Peoples’ Choice
International House Sydney (IHS) sits in an awkward and overlooked thoroughfare in Barangaroo South. Three buildings comprising International Towers Sydney cramp the new Tzannes building between two key pedestrian access points for Barangaroo: Napoleon Bridge and Shipwright Walk on one side and Exchange Place, Sussex Bridge, and Wynyard Walk on the other. These surroundings challenged the design of International House Sydney and influence how bespoke and novel the design appears against the conventional steel and glass of city skyscrapers.
Functionally, International House Sydney is a commercial building with a two-storey colonnade running alongside Sussex Street and a two-storey covered plaza that acts as the end point of Mercantile Walk.
It is a fully timber-framed mid-rise commercial building including both retail and office spaces. The cross-laminated timber (CLT) frame makes it the first engineered timber office building in Australia. The technology was originally developed in Switzerland in the 1970s but was developed and implemented by Lendlease in this project. Tzannes describes the challenges of using timber at such a large scale as “hav[ing] turned the structural limitations imposed by the use of timber to advantage and celebrated them”. The final product is indeed distinctive and evocative of a process grounded in the natural.Construction with CLT is much like pre-cast concrete, another more conventional building technique, but the pieces are much lighter and reduce construction time by allowing on-site alterations. These particular panels are fabricated out of European spruce imported from Austria.
CLT forms the entirety of the floor and walls of the interior and creates a natural wooden warmth to a space that is typically associated with cold metals and glass materials. Without ceilings, the design risks cluttering the interior visuals but Tzannes has combated this with a consistent matte black casting for all ducting and other functional necessities. The neutral colour palette is soothing and organic in a context that traditionally provokes a more mechanical approach.Tzannes was initially inspired by the exposed framing of the Tamedia building in Zurich, designed by Shingeru Ban. Reaching wooden columns create an illusion of trees and forests in the middle of the cityscape. Tzannes’s International House Sydney is more understated with softer angles and a white-glazed brick base reminiscent of late 1930s Art Deco. Atop branching columns running along Sussex St, the 7-storey building appears to float above the passing pedestrians. In comparison to the surrounding skyscrapers, IHS balances solidity and a natural softness.
Other than the innovative design and construction techniques, International House Sydney also carries some impressive environmental ratings. It has a 6-star Green Star rating with 352 photovoltic roof panels and 2700 tonnes of carbon sequestered in the CLT frame. The location allows for temperature control with a heat exchange with the nearby Harbour. The colonnade is even made from recycled ironbark.In-keeping with the spirit of both Tzannes and Lendlease, the risky design and construction of International House Sydney demonstrates a movement within Australian architecture to reach for innovative and unexpected ways to fulfil conventional briefs.