PROJECT FILES: The completion of the 6-Star Green Star Design redevelopment marks the first mass-timber social housing project in New South Wales, and one of the state’s earliest Class 2 timber apartment buildings.
Completed in April 2026, the redevelopment by Homes NSW in partnership with The King’s Trust Australia delivers 75 new social homes for 130 tenants across two eight-storey towers and a separate three-storey terrace.
Featuring commercial and retail tenancies at the podium, the development is designed as a zero-car parking site, located within walking distance of public transport with dedicated bicycle parking for residents and visitors.
GroupGSA was engaged as the executive architect to deliver the pioneering project from tender to construction in partnership with the builder, Kane Constructions. Since the initial concept, designed by Johnson Pilton Walker (JPW), the project underwent several development application amendments to accommodate the use of mass timber.
Delivering Green Star rated social housing while exploring new construction methodologies requires ambition and collective resolve. We understood from the outset that this would demand more than business as usual.
Sustainability
It’s the first 6 Star Green Star Design and first fully electrified social housing development in Australia. It is also currently undergoing Green Star’s ‘As Built’ certification process.
The project exceeds market housing ADG performance standards for daylight access, cross ventilation, accessibility and amenity:
- 85 per cent of dwellings have dual outlook
- more than 80 per cent of units have greater than 2 hours of solar access
- more than 80 per cent of dwellings have cross ventilation
- apartments feature ceiling fans instead of air conditioning – the brick’s high thermal mass provides good internal comfort and passive climate control
- 28 per cent of dwellings are adaptable to Liveable Housing Australia’s Silver Level, double the City of Sydney target of 14 per cent
- rainwater reused for irrigation
- fully electrical building
- Both roof terraces feature solar PV shade canopies
- 20 per cent more cycle parking than the City of Sydney requirement
Above ground level, all floors and internal walls, excluding the lift shaft, are constructed from CLT, with the timber exposed as feature walls throughout each apartment.
Speed meets tradition
One of cross-laminated timber (CLT)’s greatest advantages is speed. At Glebe, the eight-storey apartment floor was erected in as little as two weeks, while the three storey-terraces were fully completed in just three weeks.
More than 2500 cubic metres of CLT and glulam were used in the construction.
The integration of a traditional brick façade, selected to respond to the surrounding historic terraces, introduced a slower, labour-intensive layer that disrupted sequencing. Bricklaying lagged behind the CLT frame, delaying weatherproofing and extending the construction program to two and and half years.
The project was initially expected to complete in early 2025, but due to a range of factors, it wasn’t finished until early 2026.
In general metrics, CLT took two weeks per floor, for a total of 4 months. Brick will take on average three to four weeks per level. Bricklaying can only happen after CLT is finished. If it were a prefabricated facade system, they could easily half the time or even complete the facade almost simultaneously with CLT.
The lag is not simply because bricklaying takes more time, it’s also the knock-on impact it had and that CLT was not weatherproof until the brick facade is complete. They had to put temporary weather protection in place, which also took time. They couldn’t complete many tasks which otherwise would have been completed sequentially.
Innovation came through adaptation. The team introduced a mix of dry-pressed and extruded bricks to ease labour demand and increase cavity ventilation well beyond standard practice.
While a prefabricated façade system may streamline future projects, the outcome here is deliberately contextual. The buildings sit quietly within their streetscape, already mistaken as something that has “always been there”.
Writing the rules
The scarcity of open-source guidance for CLT in Class 2 applications required rigorous testing, detailed problem solving and disciplined coordination. Modelling was developed to level of development (LOD) 400 and beyond, with a federated BIM model integrating all consultant inputs.
In contrast to conventional construction, where some clashes are resolved on site, CLT demands precision upfront. Every brick was modelled. Every penetration, junction and interface was determined before fabrication. Clash detection tools were used extensively, ensuring each element was coordinated to the millimetre.
We used Autodesk Navisworks for clash detection to taking advantage of its LOD 400 model. It is a powerful 3D project review and Building Information Modelling (BIM) coordination software used in architecture, engineering, and construction. It aggregates 3D models from design applications, allowing teams to perform clash detection, simulate 4D construction schedules, and collaborate effectively before building begins.
This level of resolution came at a cost. As a prototype, the project required significant research, accounting for approximately 70 per cent of the design effort. But it also established a baseline. Future CLT apartment buildings will build on this precedent, benefiting from the technical groundwork laid here.
Unexpectedly, CLT proved more forgiving than anticipated. Compared to concrete, it allows greater tolerance, simplifies penetrations and eliminates reinforcement clashes. These efficiencies, once understood, can reshape how buildings can be detailed and delivered.
Navigating risk, fire and climate
While Australia is not short on sustainable building ambitions, regulatory frameworks have not kept pace with mass timber construction. The Glebe project is classified as a Type A construction under the National Construction Code (NCC), which requires the highest level of fire resistance for a high-rise, high-occupancy building.
At present, there is no dedicated Australian standard for CLT in Class 2 applications. The NCC offers innovation pathways, but little practical guidance.
The Deemed-to-Satisfy pathway, created in 2016 in the NCC, permits fire-protected timber building systems for multi-residential, hospitality accommodation and office buildings up to 25 metres (eight storeys) with sprinkler systems. In 2019, this was expanded to include schools, retail premises, hospitals and aged care facilities.
However, taller or more complex timber buildings often require Performance Solutions, involving detailed analysis and documentation to prove compliance.
The combination of brick and CLT required innovative solutions to satisfy both code compliance and constructability. At present, there is no dedicated Australian Standard for CLT, like the equivalent of the European Standard.
As a result, almost every aspect of the project, from fire behaviour to structural performance, relied on Performance Solutions, which uses British Standards and international precedents, and often privately held technical documentation, which came at a cost.
Performance Solutions is an alternative, performance-based approach using evidence, such as testing and simulations, to demonstrate that a design meets performance requirements. Furthermore, for Type A construction, CLT is generally required to be encapsulated with fire-rated plasterboard, while external wall systems are required to comply with the NCC non-combustibility requirements.
Despite decades of international evidence, CLT in Australia is still framed as “combustible timber”, triggering understandable caution from approving authorities despite behaving very differently from lightweight timber. In fire conditions, CLT chars and forms a sacrificial outer layer that self-insulates, starving the inner structural layers of oxygen and arresting further combustion. Its performance is often considered more predictable than steel, which bends under heat.
As a result, almost every aspect of the Glebe project relied on Performance Solutions. Fire behaviour, structural performance, moisture management, even how plasterboard is fixed to a CLT wall had to be individually justified, tested and documented.
While this behaviour is well understood internationally, the absence of local standards shifts risk onto project teams.
Climate added another layer of complexity. Unlike the cold, dry European environments where CLT is widely used, Australia’s humidity and rainfall present challenges for moisture management. Timber requires breathability, yet regulatory uncertainty often necessitates encapsulation behind fire-rated linings, limiting its exposure and performance potential.
Supply chains further complicate the equation. Although the project used Australian-grown radiata pine, local manufacturing capacity remains limited. In some cases, transporting timber domestically can result in a higher carbon footprint than importing CLT, highlighting the need for investment, scale and policy alignment to support the sector’s growth.
Looking ahead
There is currently no straightforward Deemed-to-Satisfy pathway within the National Construction Code for this type of exposed CLT construction in a Class 2 (multi-residential) building. While a typical house can generally demonstrate compliance using a Deemed-to-Satisfy solution, more innovative projects require Performance Solutions supported by detailed evidence, testing and modelling.
CLT is not the answer to every brief, but it is a viable one when its strengths are matched to the right building type, scale and context.
The Glebe project establishes an important precedent in construction methodology for future built forms using mass timber and modern methods of construction, particularly in Class 2 apartment buildings.
If Australia is serious about sustainable, affordable housing, projects like this cannot rely on exceptional clients, exceptional risk tolerance, and exceptional fees to deliver them.
Australia needs nationally accessible guidelines, publicly available testing, and a regulatory framework that supports innovation while providing certainty.
Mass timber is already being used. The question is whether our regulatory system will catch up to support its wider adoption.
In that respect, the Glebe project provides an important precedent for future Australian CLT developments.
Project details:
Design Architect: JPW
Contractor: Kane Constructions
Structural, civil, facade and construction engineering: TTW
Brief Collaborator: Kings Trust Australia (Prince’s Trust)
Executive Architect & Lead Consultant: GroupGSA
Landscape Architect: Turf Design
Planner: File Planning
Structural & Civil: Van der Meer
Services: Donnelly Simpson Cleary
Quantity Surveyor: MBM
Sustainability: Introba
Accessibility: ABE Consulting
Façade: AECOM
Transport: Arup
Heritage & Archaeology: Extent Heritage
Public Art: Dennis Golding
Construction Phase Team
D&C Contractor: Kane Constructions
Structural & Façade: TTW
Services: IINGEN
Fire: Scientific Fire Services
BCA: Jensen Hughes
Acoustics: Pulse White Noise
Certifier: Philip Chun
The Project Files tell the stories behind the architecture, design and business case of interesting sustainable projects. If you want to take part in this, send a note to editorial@thefifthestate.com.au
