By Tina Perinotto
17 February 2011 – Favourites: A glittering line-up of speakers at a Property Council of Australia lunch in Sydney in November last year provided a rare glimpse into the problem-solving, decision-making and sometimes heart-stopping dilemmas behind Sydney´s first high rise six-star Green Star office building at 1 Bligh Street.

Architect Christoph Ingenhoven, visiting from Düsseldorf, Germany provided a taste of how he and Australian firm Architectus arrived at an oblique solution to the site.

Also speaking was Victor Hoog Antink, chief executive officer of developer Dexus, who must have lived a few lifetimes at the moment he gave the thumbs up to the massive project – just as the global financial crisis started to reveal its killer fangs.

The architect and developer were joined by Daniel Grollo, head of the builder Grocon, who somehow had to find ways to meet the assurances he´d given for a greener-than-green tower worthy of six stars at a time when currency shocks punched million-dollar holes in budgets for some of the imported high-tech elements.

Among the bright ideas that contributed to the project’s success was the building’s elliptical shape. The new tower would be positioned unconventionally at the rear of its site, have a stunning curved atrium and be sheathes in a curved double skin façade that would stetch right around the building, rather than stopping at the three-quarter mark, a decision which, surprisingly, contributed to savings.

There would be new green concrete (now patented worldwide), blackwater treatment, 90 per cent water-recyling, innovative solar and co- generation energy.

The architects

Right from the start, said Ingenhoven, the site made it a challenging project. A conventional rectangular building would have meant a “shoulder to the harbour” and the loss of potentially brilliant views. A great deal of time was spent on the building’s orientation until inspiration delivered an elliptical shape, maximising views for tenants and the neighbourhood.

The plan to push the building hard up against its rear boundaries contravened letter-of-the-law building codes. But what was lost in strict adherence to rules was given back in spades with a generous public thoroughfare at its wide, open frontage and in overall height, modestly less than permitted.

The reward was not a single objection from the neighbours and broad acceptance by Council and industry.

The design, said Ingenhoven, allows passers-by and workers to “see and feel the whole of the community of the building”.

“It allows an open flow for people, completely open, a completely accessible ground floor,” he said.

The downside was that an elliptical shape would be more costly than a rectangular shape. The pay-off was a magnificent curved atrium at the building’s core; like the hollow of a tree that provides sanctuary to its inhabitants – and which would have a forecast air temperature range of between 20 and 25 degrees.

The building scored 84 Green Star points from a possible 100, with extra points awarded for its 40 per cent recycled concrete and 90 per cent recycled steel.

But that was just the start of the building’s differentiation in sustainability. During a visit last year The Fifth Estate team was most struck by the double skin facade…that wasn´t.

Two skins for sure, but not in the conventional way used in European buildings, where the intention is to seal in heat by incorporating an extra thermal layer of air. The thermal skin of 1 Bligh is designed to help the building stay cool – to allow air to circulate by expelling it through vents at the top of each level and to protect the mechanised metal blinds from being buffeted by wind.

Owner/Developer Hoog Antink admits he was at first sceptical about the design competition that resulted in Sydney´s greenest office high-rise, but he now views it as a “stunning result”.

Ingenhoven thought the design competition unusual but loved the bonus it provided to the developer. “What surprised me was that you get an extra 10 per cent floor [space] for design excellence,” the German architect says. “It´s an extra 10 per cent that makes it possible for developers to provide the quality.”

Another unusual element was the requirement by DEXUS that the project be entirely built using the 3D documentation method, which means that every item of the building design is digitalised and therefore harmonised, saving thousands of hours in the redrafting of plans normally required through conventional design every time a change is made. This was important to DEXUS who would manage the building on completion.

The 3D method also allows high-level planning of the facilities management regime for the building after construction because the location and lifespan of every maintenance element, down to the light bulbs, is mapped.

The 3D idea was new for everyone – the Ingenhoven/Architectus team and Grocon included. “It didn´t mean they needed to have the skills,” Hoog Antink said, “but they needed to commit to having the skills. It means there is less cannibalisation of products and more productivity on site.”

It was also a way to integrate the building information with the building tenancies, he said.

Even with 3D the entire process took 10 years, with completion expected in the middle of this year.

Victor Hoog Antink

Pushing the Go button

Dexus started by amalgamating a number of sites for the project, a process that took several years on its own. By the time it came around to awarding the building contract it was fairly clear “the world was in the middle of the GFC”, Hoog Antink said.

“We awarded the building to Daniel [Grollo] but in doing so we can´t say we saw what was going to happen,” he said. “In the normal prudential [process] we entered a two-phase construction contract that allowed us to stop at the end of documentation within a certain time-frame in the event that something unforeseen happened.

“And lo and behold it did, and Daniel and I had some interesting tussles about the pricing. At the end it came down to us having to make a call.”

It´s at this point you start to get a sense of the risks and what it takes to be a developer of a project on a scale such as this.

Hoog Antink continued. “We looked at the options of closing down the site when the GFC struck, at the end of ’08. We had anchor tenants but if we didn’t go ahead they would recommit to the premises they were in.”

Hoog Antink then made an interesting observation. Among his criteria for the decision was a consideration you would never find in the valuation books: it was the need, he felt, to consider the “social cache to Dexus and the property industry as a whole of going ahead with the project – and to me that´s worth a premium.

“I won´t say it was the thing that put us over the edge but it did help. To my view it was something we had to do. But it was also faith in the product and the site,” he said.

So how do the (financial) numbers stack up today? “We are exactly where we thought we would be,” Hoog Antink said. “We have not had a variation on the construction side of the ledger, so from a cost point of view we´ve been right on target.”

The builder´s story

In terms of quality, Grollo said, 1 Bligh Street is first class; the first time a six-star rating has been achieved in a high-rise tower.

“It´s a level of quality you just don´t see in the Australian market,” he says, “and it will be very evident [on completion].”

Did it cost more?

“It certainly cost more,” he said.

Grocon builders took a “very artisan approach” to the project, Grollo said. There was curved glass to source – an extra $20 million alone – the louvres and the operation of the louvres, for a start.

Currency fluctuations compounded problems, he says. “The problem of fluctuations [during construction] on the site was more than any other site we´ve been on. In one package alone – in the lifts – the currency changes made a $5 million difference.

“You try to work it out; to pick it up in other areas.”


When it comes to leasing the building Hoog Antink was confident. “There´s very little new product coming onto the market and there are good prospects going forward,” he said. “There´s been no kickback or resistance from a pricing point of view.

“We think this is a timing issue, not a value issue. We sit comfortably where we are.”

Rent will be in excess of $1000 a square metre on a net face basis and in a climate where incentives are coming down, Hoog Antink said.

Lead tenant Clayton Utz “would not have come if the building didn´t achieve six stars,” the developer says, “and there were penalties to Grocon if they didn´t get the six stars.”

PROJECT TEAM: 1 BLIGH STREETDEXUS Property Group/DEXUS Wholesale Property Fund/Cbus Property – Co-ownersGrocon – Design and Construct ContractorAPP Corporation Pty Ltd – Project ManagerIngenhoven/Architectus –Architects Rider Levett Bucknall – Quantity Surveyor Cundall – Sustainability consultantEnstruct – Structural Davis Langdon – Principal certifying AuthorityPhoto: The Fifth Estate

Managing the process

In a separate interview about 1 Bligh Street Tony Gulliver, the head of development at Dexus, made the point that the sustainability aspects of the building were the driving influences behind a lot of the architecture.


The perception was that a double-skin facade would be too expensive, but it was “top priority from an energy efficiency point of view,” Gulliver says. “The outer glass isn´t weatherproof; it´s basically a wind and rain shield to keep off the moisture so the cavity is naturally ventilated.”

Gulliver explains the concept. “Every window has computer controlled blinds that operate in pairs linked to a computer program which also knows when the sun is behind an adjacent building,” he says. “This enables a massive reduction in heat gain, which our engineers say will cut the air-conditioning load by 50 per cent.

“The blinds are a solar protector – they don’t have to use heavily tinted glass, which means when the sun is not hitting the building you get beautiful daylight penetration.”

And neither will the building produce the mirrored glare that highly tinted glass creates. Even at night.

The 3 metre by 1.6 metre glass panels for 1 Bligh Street were fabricated in Brisbane with glass supplied from China and the US.

The automated wide-blade blinds will be a huge boon, Gulliver says. “People do pull their blinds down and leave them down; they just forget. But these will always open when the sun is gone.” The operation of the blinds is so quiet that “people won´t notice,” he says.

There are also elements on the facade at each floor level to help deflect wind shear.


The atrium is on the southern side of the building, “where it should be,” Gulliver says. “The best side for an atrium is facing south, so you never have direct sun coming in.” Instead there will be a softer southern light.

With areas opening onto the atrium, tenants will be able to access natural ventilation without leaving their floor. “People working long hours will notice the benefits of this,” Gulliver says.

“The ground floor can be totally opened. It´s not just about energy; it´s about comfort and a healthy environment to work in.”

Air quality

Gulliver says higher than usual weighting was given to energy, water and indoor environmental quality, such as access to natural ventilation. “We weren´t doing that to get more green stars; it was to get a better building,” he says.

“We tried to deliver a building that will compete against other buildings in 10 years – after the first lease cycle has finished.”

Gulliver thinks the next big leap in office buildings will be a far wider use of natural ventilation.


Other big notches on the Green Star ladder are the high levels of recycling: a massive 94 per cent of the concrete, steel, glass and cabling from five buildings that were demolished on the site have been recycled. This illustrates huge change in the industry over the past 10 years, Gulliver says.

Water and energy

Also for the first time a Sydney CBD building has been granted a licence to remove sewage from the city’s sewerage system for use in the building’s blackwater recycling.

All the water that will be used in the building will be 90 per cent recycled, which is up to 100,000 litres a day, mostly for evaporative cooling towers and flushing toilets.

The building will also be generating power with tri-generation gas turbines producing 750kW. Solar collectors on the roof create energy through steam. “The solar energy collector is a bit like a high-tech version of solar power heating,” Gulliver says.

“There is sub-floor heating in the foyer which will warm the atrium. It’s very cost effective.”

Savings to the bottom line

Projected energy and water use will deliver a $50 per square metre saving in outgoings, Gulliver says, as compared to traditional premium buildings.

It’s about the profile

Clayton Utz, Gulliver says, wants to attract the best graduates and the building will be part of the lure.

The team management

So how was it all achieved? “We did our own due diligence…used multiple consultants” Gulliver says.

“Grocon did a brilliant job, underscored by the fact that two-and-a-half years into the project there hasn’t been a single claim for a variation.

“To get a project of this complexity, with so many issues that were unique, and to have no contractual claims, it’s very unusual,” he says. “Commonly there would be hundreds.”

Also key to the project’s success is that all the consultants collaborated, Gulliver says.

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