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100 Mount Street. North Sydney. Australia

DEXUS Property Group
Building Construction Engineering Expertise
$200 million
Project partners
Skidmore, Owings & Merrill (SOM) and Architectus

100 Mount Street. North Sydney. Australia

NSW Minister Jillian Skinner MP and North Sydney Mayor Jilly Gibson joined Laing O'Rourke and DEXUS Property Group to turn the first sod on site

100 Mount Street. North Sydney. Australia

100 Mount Street. North Sydney. Australia

100 Mount Street. North Sydney. Australia

100 Mount Street. North Sydney. Australia

Full project details

Laing O’Rourke is building North Sydney’s largest and tallest commercial tower on behalf of DEXUS Property Group, incorporating the latest innovations in high rise design and construction.

100 Mount Street is a development site in the heart of the North Sydney CBD on the corner of Mount and Walker Streets.

The landmark building is under construction and will deliver over 40,000m² net lettable area of premium high-rise office accommodation. 

Two existing buildings (90 and 100 Mount Street) have been demolished to make way for the new 44 level tower, which includes six basement levels and two ground-floor retail areas. 

It will be the tallest building in North Sydney, and it has been designed to achieve a 5-Star Green Star Design and As-Built v1.1 rating and a 5-Star NABERS Energy rating. In what will be North Sydney’s premier commercial site, the tower includes:

  • 34 levels of office accommodation with an average floor plate greater than 1,200m²
  • An open  public space at ground level and two ground-floor retail areas
  • End of Trip Facilities providing amenities such as change rooms, showers and lockers with naturally ventilated breakout spaces
  • A highly-efficient double skin facade which significantly reduces solar heat load; and
  • Premium quality finishes and services, with basement parking for 113 vehicles.

Beautiful sustainability

A key feature will be 15m clear span, open-plan floor plates which maximise the total floor space on each level. 3.1m floor to ceiling perimeter glazing will provide views to Sydney Harbour and is also an important part of the building’s environmentally sustainable design.

In addition to providing magnificent views of one of the most beautiful harbours in the world, the glazing maintains a high thermal performance via an innovative closed cavity façade with integrated blinds. A full active chilled beam system will also minimise heating, ventilation and air conditioning energy consumption.

Efficient modularised roof-top plant rooms and services risers have been used in the design, taking their manufacture into a controlled facility with simple assembly onsite to improve the construction programme and minimise impacts on local stakeholders.

Digitally empowered delivery

This project is showcasing Laing O’Rourke’s Digital Engineering capabilities. A digital model has been developed to enable the way we go to work to deliver the project’s demolition and construction works, and will also be used to link specific operation and maintenance information.

Located in one of Sydney’s busiest business districts, the construction methodology is critical to minimise street closures, the number of visits to site from construction traffic and general impacts on the surrounding community. By modelling innovative construction approaches, the digital model allows the team to test different approaches and select the best solution. The digitally engineered model has allowed our team to conduct enhanced community and stakeholder engagement activities, providing virtual tours of the entire building to identify potential issues and solutions well before setting a foot onsite. 

Follow the project on Twitter:  @100Mount 

Project updates 


March 2017 - temporary road closures (work cancelled due to inclement weather)

25 - 31 March 2017 - out of hours works

April Community Update (rescheduled tower crane installation works will go ahead this weekend)


April 2016

May 2016

June 2016

Changed parking conditions