55 King Street + 555 Collins Street. Image : Colliers International

An Amendment C270 case study: 55 King Street and 555 Collins Street

A few weeks ago it was reported that Charter Hall had acquired a future development site at 55 King Street for $78.5 million. The site neighbours the vacant 22,000-square-metre building at 555 Collins Street which owners Fragrance Group are looking to offload following failure to receive approval for a 90-storey 300 metre residential tower on the site.

The possibility of Charter Hall acquiring the site led me to wonder what the development potential of the combined sites may be, particularly now that Planning Scheme Amendment C270 looks set to be introduced by the end of the year.

55 King Street and 555 Collins Street in their present form.

What we know so far about Amendment C270 and how it might apply to a potentially consolidated 55 King Street and 555 Collins Street site:

  • Introduction of a floor area ratio (FAR) of 18:1.
  • The maximum FAR in the central city can be exceeded if there is a demonstratable public benefit. The public benefits can take the form of public open space, office uses, public space inside the building or social housing contained within the building.
  • Buildings up to 80 metres in height may be constructed up to one side or rear boundary if a minimum setback of five meters is met to to all other side and rear boundaries.
  • By default podiums will be limited to 20 metres in height with the discretion to increase it to 40 metres to match existing streetscapes and on certain street corners.
  • Towers will need to be set back at least five metres from the podium edge and likewise there will be a minimum side and rear setback of five metres for proposals which include a tower measuring 80 metres or less.
  • For proposals which include a tower taller than 80 metres, side and rear setbacks of 6% of the overall height will be required.
  • No additional overshadowing of the Northbank 15 metres from the river edge between 11am and 2pm on June 22nd.

As the above diagram illustrates the combined site area of both buildings is in the general vicinity of 3,720sqm. Applying the FAR of 18:1 yields a Gross Floor Area of 66,690sqm.

This means that the site extruded to the full extent of its boundaries would hold an 18-storey tower, however based on a 20 metre podium this would actually result in a building of 22-storeys with an overall height of 84 metres.

Extruded site vs tower and podium typology.

Working on the theory that Charter Hall might seek to develop the site into a commercial office tower, let's assume the floorplates can come down in size to allow for a taller tower with better views and a floor plate in the vicinity of 2,170sqm.

This allows for an additional five floors to be added but also requires an increased setback from the western boundary so based on a 104 metre tower that equates to a 6.2 metre setback. At 104 metres, this is only 12 metres taller than the existing Enterprise House building currently occupying the site.

Increased setbacks to allow for a taller tower.

The story is very different if a residential scheme were considered for the site. A tower of 48-storeys atop the 5-storey podium would yield a project with an overall height of 164 metres and 1000 sqm floor plates which is not too dissimilar to the likes of Victoria One, Lighthouse and Empire.

Pushing the tower as far north to the site as possible also deals with the overshadowing issue to Northbank.

Comparison of residential tower to commercial tower opportunity

Based on this very brief study it would seem that we can still expect tall, thin residential towers albeit on much larger sites and employing a true tower and podium typology.

Commercial towers appear to be constrained by the requirement from tenants for larger floor plates, although this may see a shift back to smaller floor plates in order to allow developers to go taller with office buildings in the future meaning less bulk buildings with greater separation.


Michael Berquez's picture

Great educated article you've written there. Well done.

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3000's picture

Surely this massive floorplate trend in office buildings will end eventually.

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johnproctor's picture

I'd be interested in peoples comments on, (putting aside overshadowing of the river for a second) , in the office tower example what difference it would make if that tower were the same height as the residential building?

If the FAR didn't exist but the new setback requirements did exist, along with required wind modelling etc. what is the difference in the outcome to the City? For me it would be very limited - a comparison would be the 121 Exhibition Street office tower (southern cross site). Would it matter if that tower was 60m shorter to slavishly meet these new rules? Remember I am not asking of 121 Exhibition is a good design outcome - I'm asking if the design was simply 60m shorter (as may have been the case under these rules) would it be any better an outcome for the city?

Also one thing I don't think you've considered here Laurence (although it is a bit of a mytery exactly how it works) is that Office space is an offset allowable under the FAR measurements... So in your first example as a fully office tower I assume the FAR can be exceeded?

As I understand it from the below link your example of 67,000sqm in the 'western core' would be worth $7500 per sqm as a residential use (~$500 million devleopment value). and $7000 per sqm as commercial use. dividing the development value by the commerical use and you get a new allowable limit of ~72,000sqm which is 2 additional floors at your ~2000sqm floor area.

Similarly if you made the podium in your resi tower commercial space you might get an extra floor or two on the apartment tower. The landowner may also choose in developing a residential tower to put in place social housing (which I think allows a 1:1 floor space uplift in FAR) or they may offer to provide a portion of the site to City of Melbourne as a park (which might be worth an extra 1-2 floors on top of the building depending on the size of area gifted).

(also did you alter the setbacks for the residential tower based on the increased height?)

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theboynoodle's picture

Surely this massive floorplate trend in office buildings will end eventually.

Why? Larger floorplates are better in almost every way. They are more flexible (you can make a large plate smaller, but not a small plate larger), they are more efficient (less space lost to the core).

There can be situations where you'd rather be split over multiple levels than all along a big floorplate.. nipping up a lift/flight of stairs might be quicker than walking across a large office.. but that's a marginal thing, and relatively rare. If you look at things on the scale of the new Apple campus then you can see what sort of setup a company with unlimited resources goes for.. so there doesn't seem much fear that Melbourne CBD is going to find itself delivering large floorplates that nobody wants.

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Aussie Steve's picture

I personally don't have an issue with height per se, the issue I have is about good design and overshadowing and setbacks and podiums and public realm.

It is vital that the overshadowing requirements of the planning scheme are met and not tampered with, as they are clearly there to meet the requirements of daylight/sunlight at ground level, this the public realm. With regards to setbacks, it is vital that we stop building apartments within long skinny floor plates whereby the windows for habitable rooms are just too far away to make the room liveable. I have seen it too often now, whereby apartments are built, with no windows in a bedroom, or borrowed light from adjacent rooms or long narrow spaces with a token window at the end to meet basic requirements. This is a poor outcome. If a development can be built to boundary and meet good design outcomes, then go for it.

There is really no need for office towers to be set-back from their neighbouring office towers. We already have walls of office towers along some of our CBD streets and as far as I’m concerned, it is ok. If we want podium office towers, let them be built along St Kilda Road where there is a requirement to do so. The CBD is for high density not medium, as show in the diagram above.

I would prefer to see a taller office tower set-back slightly to respect adjacent heritage buildings to form a podium, but not a flat podium across the entire site and then a tower at one end that reaches for the sky. That is a wasted opportunity and not necessarily a good outcome.

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