181 William Street
Height 123 m / 404 ft
Floors 27
Official Name

The current legal building name.

181 William Street
Other Names

Other names the building has commonly been known as, including former names, common informal names, local names, etc.

CBW, 538 Bourke Street

CTBUH collects data on two major types of tall structures: 'Buildings' and 'Telecommunications / Observation Towers.' A 'Building' is a structure where at least 50% of the height is occupied by usable floor area. A 'Telecommunications / Observation Tower' is a structure where less than 50% of the structure's height is occupied by usable floor area. Only 'Buildings' are eligible for the CTBUH 'Tallest Buildings' lists.

Architecturally Topped Out
Structurally Topped Out
Under Construction
On Hold
Never Completed
Competition Entry
Proposed Renovation
Under Renovation
Under Demolition
Completed, 2008

The CTBUH follows the United Nations's definition of Country, and thus uses the lists and codes established by that organization.


The CTBUH follows the United Nations's definition of City, and thus uses the lists and codes established by that organization.


A single-function tall building is defined as one where 85% or more of its usable floor area is dedicated to a single usage. Thus a building with 90% office floor area would be said to be an "office" building, irrespective of other minor functions it may also contain.

A mixed-use tall building contains two or more functions (or uses), where each of the functions occupy a significant proportion of the tower's total space. Support areas such as car parks and mechanical plant space do not constitute mixed-use functions. Functions are denoted on CTBUH "Tallest Building" lists in descending order, e.g., "hotel/office" indicates hotel function above office function.

Structural Material

Both the main vertical/lateral structural elements and the floor spanning systems are constructed from steel. Note that a building of steel construction with a floor system of concrete planks or concrete slab on top of steel beams is still considered a “steel” structure as the concrete elements are not acting as the primary structure.

Reinforced Concrete
Both the main vertical/lateral structural elements and the floor spanning systems are constructed from concrete which has been cast in place and utilizes steel reinforcement bars.

Precast Concrete
Both the main vertical/lateral structural elements and the floor spanning system are constructed from steel reinforced concrete which has been precast as individual components and assembled together on-site.

Utilizes distinct systems (e.g. steel, concrete, timber), one on top of the other. For example, a steel/concrete indicates a steel structural system located on top of a concrete structural system, with the opposite true of concrete/steel.

A combination of materials (e.g. steel, concrete, timber) are used together in the main structural elements. Examples include buildings which utilize: steel columns with a floor system of reinforced concrete beams; a steel frame system with a concrete core; concrete-encased steel columns; concrete-filled steel tubes; etc. Where known, the CTBUH database breaks out the materials used in a composite building’s core, columns, and floor spanning separately.

5 Star Green Star

Height is measured from the level of the lowest, significant, open-air, pedestrian entrance to the architectural top of the building, including spires, but not including antennae, signage, flag poles or other functional-technical equipment. This measurement is the most widely utilized and is employed to define the Council on Tall Buildings and Urban Habitat (CTBUH) rankings of the "World's Tallest Buildings."

123 m / 404 ft
To Tip
123 m / 404 ft
Floors Above Ground

The number of floors above ground should include the ground floor level and be the number of main floors above ground, including any significant mezzanine floors and major mechanical plant floors. Mechanical mezzanines should not be included if they have a significantly smaller floor area than the major floors below. Similarly, mechanical penthouses or plant rooms protruding above the general roof area should not be counted. Note: CTBUH floor counts may differ from published accounts, as it is common in some regions of the world for certain floor levels not to be included (e.g., the level 4, 14, 24, etc. in Hong Kong).

Tower GFA

Tower GFA refers to the total gross floor area within the tower footprint, not including adjoining podiums, connected buildings or other towers within the development.

49,200 m² / 529,584 ft²
Construction Schedule

Construction Start



Cbus Property
Structural Engineer
MEP Engineer
Project Planning and Management Pty Ltd

CTBUH Initiatives

Warm Weather Spaces Walking Tours 2015

17 September 2015 - Building Tour

About 181 William Street

181 William Street is a new major corporate presence in the high ground of the west end commercial precinct of Melbourne. The entire project is designed on a holistic basis to integrate the façade with all services systems to achieve high quality environmental performance. During the course of a comprehensive design process, all services systems were integrated to ensure high quality environmental performance, flexibility and long life.

The tower façade is visually arresting in the use of colors in the vision and spandrel glass, creating a balanced geometric pattern that captures a sense of movement across the façade. The russet color pallet was selected to reflect a richer and more distinct corporate presence. The range of seven colors to the spandrel and vision glass has been distributed in an ordered manner that has been inspired by the dot painting technique of Australian indigenous art. The white columns are metal clad with the lower sections expressed in polished stone. The elevated podium is clad in zinc with expressed joints and flush glazing to match. The north and south inset façades are in clear flush glazing.

The tower is designed to achieve maximum natural light, views and workplace flexibility. The project has achieved a certification rating of Five Green Stars and 4.5 Star ABGR. These rating systems are administered by the Green Building Council of Australia and subject to rigorous audit and monitoring. These assessments cover all elements of sustainable performance, including the consideration of embodied energy, recycled construction materials, indoor air quality and VOC analysis, and ongoing environmental performance. This is equivalent to a LEED Gold rating.

17 September 2015

Warm Weather Spaces Walking Tours 2015

The CTBUH Urban Habitat / Urban Design Committee organized guided walking tours of 16 cities around the globe, focusing on urban habitats around tall buildings.

Submit images or information about this project using the Data & Image Submission Portal