Arc by Koichi Takada Architects stands apart for its brickwork, rooftop arches

Designed by Australian firm Koichi Takada Architects, Arc is a multi-residential building located in the heart of Sydney. The design combines craftsmanship and texture to create innovative contemporary towers that respond to the rich historical context of their surrounding urban fabric.

Two 26-storey towers with a distinctively arched roofscape is not the only extraordinary element in Sydney’s skyline, the façade also brings an intriguing and striking appearance to the city. Inspired by the heritage buildings in the area, the two slim towers rise from an 8-storey masonry podium. The unique brick façade of the podium blends seamlessly within the delicate historic context, creating a public through-site connection between Clarence and Kent Streets. The roof has been designed with 59 fins that travel up the length of the building, culminating in an organic crown feature, instantly distinguishing Arc from the rest of the skyline.

Koichi Takada, the principal architect of the firm, explains what it was like to conceptualise and execute a modern project that embraces the past, “The concept relates to the historical context of the site. We carefully studied the proportions of the arches and materiality used historically in Sydney. People have responded to the warmth and use of traditional methods being brought back to a modern city centre where most buildings are glass and metal.”

Drawing inspiration from the characteristic arches and masonry in the other significant heritage buildings in the surroundings - the Red Cross Building and Andrew Bros Warehouse - the project introduces a duality to the façade which is represented by the varied aesthetics of the podium and tower. Where majority of the city has flat-topped buildings everywhere, the Arc explores an opportunity to open up the rooftop.

“We designed to celebrate the great outdoor lifestyle that Sydney is famous for, and the first high-rise residential design to break the mould,” mentions Takada. “We convinced the city and our clients that there is more value in using the roof for public amenity instead of private apartments – imagine a city where people can escape to the rooftop, where the architecture facilitates social interaction and the reimagining of the urban environment.”

Discussing the intricate process of construction of the two major elements in the design of the project - the façade and the roof – here’s an excerpt from STIR's conversation with the team at Koichi Takada Architects.

Meghna Mehta (MM): As the name suggests, the project was much about the ‘arc’ in the design. Could you explain in detail how each of the bricks were designed and then put together to make the Arc?

Koichi Takada Architects (KTA): When we designed the podium, we drew every single brick; approx 300,000 bricks of them in total, and built brick by brick, handcrafted, took a long time to figure out the cantilever of the bricks. The regulation allows about one-third of the cantilever, but we pushed it to 50 percent, which makes the arches appear quite light, there is so much depth and shadow. To overcome challenges, we had many dialogues and one-on-one sessions with the brick masons who also built the UTS’s ‘paper bag’ designed by Frank Gehry.

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MM: Another material for the roof was used to create the forms of the arcs, why was that? How did the marriage between different materials, brick and others, come about in the building? 

KTA: The concept relates to the historical context within the site – we wanted to connect the podium element to the heritage building. We carefully studied the proportions of the arches and materiality used historically in Sydney. The design has a heavy masonry character at the base, whereas the tower above has a finer, lighter materiality. Then we looked at the roof element – the crowning feature. We thought it was a great opportunity to change the skyline of Sydney.

Where some other cities in the world have quite prominent skylines, Sydney’s is fairly banal and the experience of it is quite weak. In the design competition, a lot of our competitors designed the building from bottom-up but no one designed it from top down. We consciously designed from both directions. - Koichi Takada Architects

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MM: Could you explain the way these were implemented on site or prefabricated for the elevation as well as the roof?

KTA: We worked on 1:1 mock-ups and tried to perfect them with the sub-contractors before they finally executed the construction on site. Having said that, there were still more challenges to overcome on site because not all arches were identical. We had to design how each junction of differing arch geometries could meet. We worked closely with the bricklayers who created custom formwork and worked precisely to brick coursing dimensions to align at each level. Bricks, as a fixed module, is not flexible at all, so we had to react on site and experiment with expansion joints as the façade was being built. It was such a pleasure talking to the bricklayers who hand-laid 300,000+ bricks on site together. Brick is the perfect demonstration of wonderful craftsmanship.

MM: The recession of layers in the arches brings about a different language in the façade. Could you explain why this was done and how this was decided?

KTA: During the initial design competition, we went to study the existing site and were struck by its delicate heritage neighbourhood with heavy masonry character.

Respecting or relating to the neighbours could have run the design risk of blending too much into the context and making our design ‘invisible’ or even unnoticed. We found a way to highlight the traditional brick in an original way, using modern design technologies to achieve something somewhat unexpected. The podium is what people are drawn to, in contrast to the glass tower which we initially thought would be the standout. 

Initially, we were torn if we should go with old or new materiality. A contemporary glass and metal materiality, for example, may have looked sexier. It was particularly tempting to stand out as a contrast for the competition against the traditional brick masonry character of the existing neighbourhood. - Koichi Takada Architects

The building covering a total area of 17,400 sqm has 135 apartments, 86 ‘Skye Suites’ boutique hotel rooms, eight retail units and F&B outlets. While retail units are at the ground level, the suites above have balconies overlooking the street and are covered by double-height arched reveals.

The distinctive design of Arc contributes to the CBD (central business district) skyline, and reflects Sydney’s vision for 2030 - a sustainable urban development scheme with an aim to change the way we live, work and play in the city; now and into the future.

Project Details

Project: Arc by Crown Group
Location: 161-165 Clarence Street & 304 Kent Street, Sydney, Australia
Architecture and interior design: Koichi Takada Architects
Clients: Crown Group
Status: Completed
Year: 2018
Site area: 1,447 sqm
GFA: 17,400 sqm
No. of apartments: 135 residences, 86 serviced apartments, 221 totals
Range of apartment sizes: 38sqm – 150sqm
No. of floors: 26 above ground and 6 below ground
No. of Bricks: 300,000 approx. (2,79,680 bricks delivered to site)
No. of rooftop arches: 59
Consulting: Van Der Meer Consulting
Builder: Hutchinson Builders
Façade Engineer: Inhabit / Surface Design
Masonry Façade Engineer: AECOM (Brick)
Bricklayer (Masonry Subcontractor): Favetti