Melbourne’s $1bn ‘Solar Highrise’ Leads Way to Office Future

With its revolutionary ‘solar skin’ facade, Cbus Property’s $1-billion tower at 435 Bourke Street is redefining the Melbourne’s CBD. The Bates Smart-designed 48-storey highrise spans several sites and comprises 60,000sq m of premium office space and 1300sq m of street-level retail space. Designed to accommodate more than 5500 workers, the tower’s ‘vertical village’ structure is tailored for post-pandemic hybrid work patterns . It will feature a sky garden, mixed-mode terraces and naturally ventilated extensions to traditional workspaces. In short, the project represents a significant step forward in sustainable office development. Bates Smart director Cian Davis says the philosophy behind 435 Bourke Street is what makes it truly innovative. Davis has been design director on the site since the Cbus Property purchase in 2018. When Covid hit in 2020, Cbus Property used the crisis as a catalyst for innovation—not just from a technical standpoint, but from a human perspective. ▲ Bates Smart director Cian Davis. “Covid changed everything,” Davis tells The Urban Developer . “It wasn’t just that the project slowed, it was more that Cbus Property used the opportunity to look to the future, to pause and say, something significant is happening here and ask, ‘what does an office building after this actually look like?’.” So, they interviewed tenants and other businesses to find out. “And what we learned was that sustainability has gone beyond a layer on a project. It’s now integral to the vision of the tenants of an office building.” Davis said businesses pledging carbon neutrality by 2030-35 are considering long-term office space aligning with these goals. Attracting top talent is also a factor. “Some big firms are in an arms race for the best graduates every year,” Davis says. “Graduates now are highly principled in terms of the way they expect the place they work to reflect their social or environmental or economic values. If you’re a big firm and your office doesn’t represent that physically, you run the risk of not attracting the best talent.” ▲ There are no real spaces like this in Australia, Davis says about the internal greenspaces in office towers. Bates Smart moved away from the “singular office building” model towards the “idea of a building as an ecosystem. An office tower that could be a diverse environment where you could work in different ways,” Davis says. The concept of the sky garden came about after ideas of “a park in the centre of the building that would be accessible by all people, to go for a walk or work in a garden; a place that you could work outside but still be a part of the building, rather than confined to inside your office”. “We thought of a lobby that is more than simply a place to wait for an Uber,” Davis says. “It’s a place you actually would choose to utilise as a meeting spot with colleagues or a place to sit with a coffee, or with food, or a change of scenery while you work. When it came to the inclusion of sustainable design principles Davis says, “We decided not to bury sustainability as a technical thing. We made it obvious. We didn’t start out with a solar facade. The solar facade came through testing. “The brief from Cbus Property was to be innovative, carbon neutral, all electric, and they insisted we find the way to get there. “And we did that by talking to people and testing our theories.” Davis says, “taking two different office typologies” is also quite an unusual concept. “The idea is that you’ve got a podium ... that is almost like a campus with an atrium and glass lifts and then sitting on top of that is a skyscraper,” Davis says. “We’ve got the tower, which is attractive to legal and professional services, or anyone looking for great views and a floor plan that’s a bit more bespoke for their business. “It’s an unusual building in that sense. And it’s quite a tricky site. It’s got a heritage laneway with a very low-scale context, which is where we’ve got the Chris Lucas restaurants going.” Chris Lucas is the man behind iconic Melbourne eateries Grill Americano, Society, Yakimono and Chin Chin with two new venues coming to 435 Bourke Street. ▲ Chris Lucas will bring an integrated commercial and dining precinct with an inherent focus on sustainability, according to Cbus. Innovation runs more than ‘solar skin’ deep on this 211m-high building. Kapitol Group, recently named among Australia’s top 100 innovators, completed the early works and basement in April last year . This included removal of the 11-story commercial building at 423 Bourke Street and portions of buildings at 140-150 Queen Street and 22 Nicole Street. Director Andrew Deveson says the excavation was “probably the biggest one done in Melbourne since VCCC”, the Victorian Comprehensive Cancer Centre, a $1-billion health facility opened in the city in 2016. The basement alone spans five-and-a-half floors and required the excavation of 70,000 cubic meters of soil. “It’s a really busy street and the need for traffic management in that area meant that creating a logistics plan was not an insignificant challenge,” Deveson tells The Urban Developer . Kapitol overcame logistical challenges by building a unique top-down construction deck, facilitating the excavation and seamless handover to Multiplex. Kapitol also pioneered the use of Visibuild, a Melbourne-based startup’s QA platform which, Deveson says, “took the site to the next level in terms of approach to quality”. Cbus Property wanted rigorous oversight and certification on the excavation and installation of piles. This included having a dedicated building surveyor and inspections of every pile. “That’s sort of where we came in,” Visibuild director, construction Ryan Treweek says. Treweek says Visibuild gave stakeholders “full visibility and traceability over the construction process” in real time to “prevent errors and save developers a lot of money”. “When Multiplex came in, they could see inside the concrete and behind walls. Things that they wouldn’t have usually been able to see with traditional means,” Treweek says. ▲ Kapitol factored in the needs of incoming builders when constructing it's top-down deck. Cbus Property is now showing interest in rolling out the platform across its other developments. “Quite often developers think quality and the way the build happens is somebody else’s responsibility,” Treweek says. “But the Cbus Property name will be on the building, and that’ll be remembered a lot longer than who built it. From our perspective, Cbus Property is now a leader in the QA space. A lot has already been written about the facade . The building will be one of the first and largest office towers in the world to feature an integrated photovoltaic (PV) system that generates electricity and allows natural light to penetrate the interior. Bates Smart designed the panels, which Davis refers to as ‘petals’, by applying bespoke toughened glass casings to “a fairly standard, off-the-line solar cell”. “We did a lot of prototyping and tested all sorts of different cell types,” says Davis. “But we’re not really inventing anything. We’re just first to market in the configuration.” BG&amp;E was involved with design and prototyping of the solar skin. Building services consultant NDY also helped design this system, which it says, “needed an innovative approach to the electrical design to help it work”. It’s connected to inverters every three levels, and channels solar power into distribution boards on each floor. DC-DC optimisers maximise panel output, even in low sunlight. A low-temperature variable air volume system, water-cooled chillers and air-source heat pumps replace natural gas boilers for higher energy efficiency. These operations will save 430 tonnes of carbon dioxide emissions per year. ▲ Bates Smart designed the structure so that every tenant could get to a piece of green space, according to Davis. The project is targeting a 6 Star Green Star New Buildings rating, 6 Star NABERS Energy rating, and a Platinum WELL certified rating. “Basically, it will be the highest-performing office building in the country,” Davis says. Multiplex regional managing director Ross Snowball says the project’s low-carbon structural solution will have “a positive and material impact on the environment” and would “reduce embodied carbon”. Using renewable fuel to power the tower cranes is expected to provide a 90 per cent reduction in carbon emissions compared to using traditional fuels. Construction is slated for completion in the fourth quarter of 2026. “They’re pouring the level eight slab this week, so it’s rocking along,” Davis says. The project demonstrates what a quality office building should be, prioritising human and environmental wellbeing, according to Davis. “And it’s testament to Cbus Property's commitment to pushing boundaries in innovation and sustainable development.” You are currently experiencing The Urban Developer Plus (TUD+), our premium membership for property professionals. Click here to learn more.

Melbourne’s $1bn ‘Solar Highrise’ Leads Way to Office Future

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