As cities around the world grapple with the challenge of revitalising ageing office buildings, the conversation around adaptive reuse has gained momentum.

Rather than resorting to demolition, developers and architects are exploring innovative ways to modernise existing structures, enhancing their appeal to tenants while aligning with sustainability goals.

Leading the design for this transformation at 52 Goulburn Street in Sydney was Architectus, whose strategic interventions, specialist lighting, and innovative use of materials preserved the building’s core structure while significantly improving its usability and aesthetic appeal.

In this interview, the design team shares insights into the principles guiding the project, the challenges faced, and the broader implications of adaptive reuse in the commercial office sector.

Architecture & Design: What were the key design principles guiding the revitalisation of 52 Goulburn Street, and how did they shape the final outcome?

Architectus: The design team had five key design pillars:

Amenity focused design - adding high quality and usable features tenants expect from a modern asset
Creating a warm and welcoming space – natural materials, warm lighting, soft furnishings and biophilia
Enhancing street presence - designing a legible and memorable street interface, based around an activated ground plane
Facilitating flexible working zones to appeal to a broader spectrum of future tenants - creating a 3^rd space with a ‘gradient of amenity’ for different types of working, collaborating and socialising
Activate underutilised spaces with high-value amenity – examining spaces that were not being used to their fullest potential, such as car parking space, the rooftop and the atrium space, and carefully crafting new amenity that focused on flexible working, wellness and social connection

How did you balance the need for modernisation with the constraints of working within an existing structure?

Originally partially constructed as a residential tower and then converted into a commercial tower during the construction process, the existing development maintained many complexities. This evolution presented the challenge of varying datums, limited street presence and a narrow circulation path within the building’s entry lobby. Our design intent for the lobby was to simplify these datums and enable a timeless design which celebrated the grandeur and rarity of the atrium height and the abundant natural light it afforded. The narrow lobby introduced specific challenges, particularly the installation of the expansive 2900 x 1500mm travertine wall panels. This necessitated meticulous planning and collaboration between the designer, supplier and contractor to navigate the intricacies of certain junctions and stone treatments. The fragmented arrangement of the existing lobby was opened up and connected into a more contiguous space, enhancing the user experience, while improving the building’s street presence at ground level.

With regards to the central atrium space and workplace floors, we operated under a stringent budget, compelling us to implement strategic design modifications that delivered substantial impact – we focused on the ‘best bang for buck’. For instance, instead of allocating funds for new floor tiles, we opted for an in-situ retreatment of the existing tiles, enhancing their aesthetic alignment with our design vision.

Furthermore, we identified numerous non-compliance issues within the original building. Operating within a constrained budget we ensured that replacement materials were consistent with the design intent of the new elements. A notable intervention is the central staircase within the atrium workplace. Originally designed as a fire egress stair, we leveraged thoughtful material selection and close collaboration with the lighting designer to reimagine this stair as a communication stair for future tenants. This approach not only conserved resources but also optimised floor space and negated the need for additional inter-tenancy staircases to be introduced by future tenants.

Can you elaborate on the specialist lighting techniques used in the lobby, and how they enhance the perception of space?

The intent was to provide warmth to the space and highlight natural materials. A datum was set at 2600mm high, this served to break down the space into a more human scale whilst still preserving the grandeur of the atrium height within the lobby. The datum assisted in providing physical relief from the textured travertine base, strategically selected to be experienced by patrons at a lower level, and the honed travertine slabs which were utilised at height to create a timeless elegance. We worked closely with the lighting designer to create a warm glow between the two textures which gently washed the travertine and celebrated the beauty of the material’s natural imperfections. A similar detail was also employed in the ceiling adjacent to travertine clad walls and around the perimeter of travertine clad columns.

Within the atrium, we envisaged a more relaxed and playful lighting scheme that celebrated the volume of the space. For this, we used spherical fittings mounted at different heights to form a floating cluster of light.

What were the biggest challenges encountered during the refurbishment, and how did you overcome them?

Budget: The existing building provided many opportunities for extensive upgrade and a greater renewal project. The allocated budget meant that the design team were required to do more with less and implement design changes in a selective and curated manner to yield the best and most transformative outcomes.
Regulations and approvals: During the project, it was found that the introduction of the end of trip on a basement floor affected some of the residential car spaces within the wider precinct of the World Square development. This triggered the Design and Building Practitioner Act legislation. As a result, this had ramifications on the overall project timeline and budget which needed to be managed by the design team, contractor and project manager.
Due to Council provisions during the approval phase the works were required to be staged, prolonging the project timeline.
The works included a connection to the neighbouring lobby which would enable patrons direct access to the local retail and food and beverage precinct. The adjacent building was fully tenanted and operational meaning these works needed to be staged to enable constant access for patrons utilising the office floors.

How do you see the trend of adaptive reuse evolving in the commercial office sector, particularly for B-grade buildings?

It’s about tapping into opportunities for asset owners to consider how an adaptive reuse of their particular property might contribute to a broader change or the potential to change an entire precinct. It’s about understanding the direction a neighbourhood is headed in – what changes lie ahead in the short-, medium- and long-term future when it comes to its personality and attractiveness, and identifying the potential for different types of tenants, and then taking that thinking into the brief development.

In recent years we have seen a ‘flight to quality’, leaving many of these B-Grade assets struggling for relevancy and tenants. Knocking them down and starting again does not always seem like the correct response from a sustainability or financial perspective. '

‘Upgrading' and 'Change of Use' are the primary options when considering reuse of an existing Commercial Office Building. The ‘Upgrade’ scenario assumes the tenant typology is retained, whilst ‘Change of Use’ contemplates modifying the building to suit an alternative use, such as an Education or Health Sciences tenant, or repositioning the asset as Residential. In all cases the base works required can fall into similar categories. A rigorous understanding of the local planning context will inform permissible uses, and the controls relating to them. This evaluation will help determine maximum site yields and potential.

Tenant amenity in commercial office buildings plays a crucial role in attracting and retaining tenants. The amenity offering enhances the overall work environment, promotes employee well-being, provides tenant flexibility, and can significantly influence a company's decision to lease office space. It's important to identify the appropriate amenity combination for buildings, including the strategy for managing these spaces.

Were there any sustainability considerations or initiatives incorporated into the project to reduce its environmental impact?

Our design team looked to incorporate circular economy principles into the design. This meant collaborating with suppliers with an aligned ethos of recycling materials now and in the future where applicable throughout the workplace floors and the end of trip facilities. The design team also looked at retreating existing materials where possible to give them a second life. This included recycling the existing floor tiles within both lobby spaces by retreating them in situ, retaining the existing escalators between the lobby spaces but retreating the stainless-steel elements to suit the selection of black power-coated metal, and also resurfacing the stainless steel lobby entry and exit portals to suit the new design direction.

Biophilic design principles were introduced into the ground floor lobby spaces to create an added warmth and more welcoming spaces. Biophilia was also introduced into the flexible working zones of the third space which sits within the secondary commercial lobby to facilitate more collaborative working zones.

How did tenant expectations influence the design choices for this refurbishment?

At the time of the initial design concept there was no agreed tenant which meant that the design work undertaken needed to facilitate for a potential myriad of diverse future tenants to give the landlord the greatest opportunity to lease the space flexibly in the future. We focused on creating adaptable spaces such as introducing short and long term flexible and collaborative work zones throughout the secondary commercial lobby space, facilitating for vertical intertenancy connectivity by upgrading the fire egress stair to visually align with the public area upgrades and to be utilised as part of a future tenancy, and introducing a high level of amenity throughout end of trip offering.

Do you believe there is a growing industry shift away from demolition towards revitalisation, and what factors are driving this change?

Yes, we’re seeing an increasing number of property owners interested in asset renewal, with key factors relating to cost, time, and sustainability.

There can be significant cost savings in adaptive reuse vs new build and subsequent upgrades can yield higher rental returns for property owners. Adaptive reuse gives older assets the potential to become competitive against newer asset alternatives which provide a higher level of amenity and performance than tenants now expect.

There's also an expedited timeline when comparing renewal with a rebuild. Where new build commercial projects can take five to seven years, adaptive reuse projects can be turned around in 12-24 months or less depending on the scope of works.

The move toward refurbishment is also positive for our environment. It can typically halve the carbon footprint of a building, compared to constructing new. There is also the potential to investigate and implement circular economy principles into renewal projects which is desirable short and long term.

How does this project contribute to the wider urban fabric of Sydney, and what impact do you hope it will have on the surrounding area?

When we were developing the brief for this project, we carefully considered the building’s context within the CBD precinct and the government’s efforts to transform the central precinct into a tech hub. We saw potential to tap into this market and attract new tenants.

We've also stitched together the precinct more harmoniously by creating connections between 52 and 50 Goulburn Street allowing employees direct access to the retail precinct within World Square. We studied existing ‘ant trails’ through the precinct to better understand how we could facilitate and optimise movement.

What lessons from 52 Goulburn Street can be applied to other ageing office buildings facing similar challenges?

The main lesson here is doing more with less. We had a tight budget and had to be clever in our approach to renewal - recycling some of the existing materials, as opposed to completely stripping out the building. We retained a lot of base build items and even some of the finishes like the flooring and retreated them to give them a fresh and modern aesthetic.

It's about being strategic with the design changes that you introduce to have the greatest impact and provide the uplift and revitalisation to these assets that will be attractive to future tenants. This is why we were quite amenity focused in our design approach as that's where the market is now. This approach was required to make this particular asset more competitive in the current market.

52 Goulburn Street also presented the potential to increase the net lettable area (NLA) in the building which is often an attractive value-add for clients where possible. In this instance, it was achieved through the introduction of a rooftop which served as an extension to the workplace for events, flexible and collaborative working and as a breakout zone. There is certainly an opportunity to apply a similar approach to other assets requiring a refresh, however it needs to be assessed on a project-by-project basis and is dependent upon whether it is possible to increase the NLA based on what the current floor space ratio (FSR) is.

Images: 52 Goulburn Street by Architectus / Nicole England Photographs

Clémence Carayol

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