Few proposed new projects have captured the attention of green building cohorts like Atlassian’s 40-storey hybrid skyscraper in Sydney. Speaking at the Green Building Council of Australia’s Transform event this week, the project’s director, Bronwyn Zorgdrager, offered a peek into some details.

The building is chasing tough emission reduction targets, including 50 per cent less embodied and operational carbon and there are plans to run off 100 per cent renewables.

There may be solar PV on the façade for instance, though this is still to be confirmed.

This new headquarters building for the tech giant interesting because Atlassian is both tenant and owner, in partnership with Dexus.

Zorgdrager told the audience this has allowed the company to take risks a developer won’t because it can’t be sure its tenants will pay for it.

“We’re not looking at this as a developer… we’re looking at how to create a home for Atlassians that we can attract and retain to the building”.

For a tech company, which is competing with companies across the world for top talent, mediocre won’t cut it.

“For a tech precinct, you don’t want to be delivering a standard building, you want to be very bold.”

She noted that there is an “interesting tension” with many advisors “putting the commercial wrap” around it.

“There is that tension between design, aspiration and what is viable. So, I think we being the tenant means we have been able to drive a lot of the ambition.”

While “doing the right thing” is a primary driver for the software company’s sustainability aspirations, Zorgdrager said that attracting and retaining to talent to the Sydney office is also a major driver. She said that existing Atlassian employees are very excited and engaged with the project.

A tower designed around sustainability criteria

At the heart of the project are three ambitious targets for lowering emissions compared to a standard office tower: running the building off 100 per cent renewable energy, reducing the operational carbon by 50 per cent and reducing the embodied carbon by 50 per cent. Zorgdrager said these targets are driving many of the design decisions, and that this is quite unusual.

The building will also be fossil fuel-free and while it wasn’t designed with standards set by the environmental rating tools from the outset, Zorgdrager said that modelling shows it will meet the top standards such as Green Star and LEED.

The project was a challenge that attracted around 50 applications from architecture practices, with a collaboration between SHoP and BVN emerging as the best choice from the shortlist of five designs. The design team was then accompanied with “best in the business” engineers and consultants, she said.

To make the most of 360-degree city views, the building is stacked with eight distributed “habitats” intended to be a discreet “neighbourhoods”. Each habitat is separated by a steel mega floor, and the floors within the steel floors are made from timber.

The rooftop will have a crenulated crown shape designed to mitigate solar load. The stunning top level views will be shared with all occupants, not just top executives in their boardrooms like in many other commercial office towers, with amenities such as gardens, events spaces and a gym. Even a swimming pool is on the cards, Zorgdrager said.

Natural ventilation up high in the sky

The high-performance external façade will also work hard to facilitate another key aspiration: natural ventilation. The team is considering PV panels to sit on the façade’s exterior on horizontal planes.  

Slashing the embodied carbon by 50 per cent is also a formidable challenge. There are two main levers to pull, Zorgdrager said, stripping out material and through “green procurement”, which is sourcing low carbon materials. This is one of the reasons timber – a material that sequesters carbon – features prominently in the design of the hybrid steel, concrete and timber structure.

The core of the building will be concrete to give it the stability it requires to straddle a heritage listed shed below.

A steel exoskeleton will wrap around the frame of the building support the building, simultaneously providing fire separation between the timber habitats.

Occupant comfort is a priority. This is where the eight habitats come to the fore. Each habitat has a lush green park space that’s naturally ventilated and intended to be used for collaborative work. This outer “skin” will provide protection from the sun though the facade as well as the structure, planting and shading.

A second internal facade with double glazed windows will contain workspace intended for focused independent work. It will be able to be mechanically ventilated, heated and cooled or, on a temperate day, windows and doors opened to lighten the load on the HVAC systems and get some fresh air.  

Rather than being stuck in a hermetically sealed, controlled indoor environment, the idea is that people will move between the two spaces to manage their own comfort, Zorgdrager explained.

The modelling so far does suggests that the outer layer will be comfortable at all months of the year, giving Atlassian, as a tenant, confidence to pay full rent for the space.

The tech company also values a flexible floorspace that can be rejigged as teams change and evolve, something Zorgdrager said is particularly important coming out of the pandemic.

Renewables are the third part of the puzzle. There may be some solar on the façade, pending the resolution of complex compliance issues, but given the height of the building and its inner-city location, the majority of its energy needs will be met by renewables projects offsite.

The three targets are being tracked in real time to ensure the ambitions are met.

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