New Zealand Parliamentary Buildings Project: a sustainability-led development

In architecture, and in the design and construction of public and private buildings, discussions about eco-friendly choices tend to focus primarily on the types of materials used. Today, however, sustainability in architecture is the result of a much broader balance, encompassing structural choices, construction processes, durability and the ability to reduce impacts across the entire life cycle of a building. Beginning with the care taken on site and how materials are assembled.

Developed as part of the Future Accommodation Strategy of the New Zealand Parliament, based in Wellington, the New Zealand Parliamentary Buildings Project is a clear example of sustainable architecture applied to a complex, multi-storey public infrastructure. The project involves the construction of new buildings, distributed across six floors, designed to accommodate Members of Parliament and parliamentary staff, with stringent requirements in terms of security, performance and environmental responsibility. From the very early stages, the aim was not simply to build sustainably, but to rethink the entire construction system in order to reduce climate impact, improve process efficiency and ensure reliable, long-term performance.

From concrete to Mass Timber: a paradigm shift to achieve Green Star 6

At the heart of this sustainable architecture project is a decisive shift away from the original reinforced concrete and steel structure. As confirmed by the design team, maintaining a Green Star 6 target with a traditional structure would have been extremely challenging. Developed by the Green Building Council of Australia, Green Star is a rating system for building sustainability. In line with other international protocols such as LEED and BREEAM, it assesses environmental performance across the entire life cycle of a building, from design and construction through to operational management. So how can high performance be achieved while fully complying with the requirements set out by the Green Building Council? As emphasised on several occasions by Aurecon, one of the companies responsible for designing the new building, the answer lay in the choice of Mass Timber – specifically, the many advantages offered by CLT.

Indeed, the decision to adopt what is informally referred to as “Kiwi timber” – wood grown and processed in New Zealand – made it possible to align the project with climate objectives starting with the very choice of raw materials.
This “cradle to grave” approach marks a genuine step change: over an estimated service life of 60 years, the building will generate 89% less climate pollution than a standard building.

A figure that, on its own, would be enough to demonstrate that architecture and sustainability do not hinge on a single material, but on a coherent structural strategy.
The use of large glued laminated timber elements and CLT panels made it possible to drastically reduce emissions associated with material production, while at the same time maintaining high structural performance.

Speed and efficiency through Design for Manufacture and Assembly

As discussed in a previous article, the design of the new parliamentary buildings addressed architectural sustainability first and foremost in terms of the construction process. The building is composed of large H-shaped structural frames made of glulam: each three storeys high and weighing up to 18.5 tonnes.

In a traditional system, constructing a single concrete bay can take between five and six weeks. Here, by contrast, the installation of two prefabricated H-shaped frames took around 1.5 hours. A stark comparison highlighting the value of Design for Manufacture and Assembly in reducing indirect impacts: less time on site means lower energy consumption, fewer disruptions and greater quality control.

The construction strategy was not conceived floor by floor, but organised into vertical sections: one portion of the building is completed from ground level to the top, before moving on to the next. This choice also had a direct impact on timber protection and the overall durability of the structure, with a primary focus on maximising the pre-installation of elements in the factory in order to speed up and simplify on-site assembly.

Sustainability starts on site: the key role of DEFENCE ADHESIVE 200

In a Mass Timber building, the material's sustainability also depends on its integrity throughout all stages of construction. Moisture on site represents one of the main risk factors: prolonged exposure to the elements can compromise performance, generate waste and reduce the service life of structural components.

In the New Zealand parliamentary project, the vertical-section construction strategy helped to reduce the timber’s exposure time. This was combined with targeted protection of the structural elements using DEFENCE ADHESIVE 200, a self-adhesive membrane designed for the temporary protection of timber during transport and on site.

The membrane provides protection for up to 12 weeks, is waterproof and does not interfere with handling operations. Once applied, it remains invisible and allows layout markings and assembly holes to remain clearly identifiable. Rather than slowing down the assembly process, timber protection thus improves its overall reliability.

Within a sustainable architecture framework, preventing the premature degradation of structural elements means reducing waste, replacements and corrective actions, thereby making a tangible contribution to lowering the building’s overall environmental impact.

Long live Mass Timber... thanks to HBS PLATE

If timber represents the backbone of sustainability, structural connections are its most critical point. In Mass Timber construction, the stiffest point is often the most vulnerable: this is where localised stresses, differential deformations and potential failure triggers tend to concentrate.

In the new parliamentary buildings project, the timber-to-steel connections were designed with particular care. HBS PLATE, the screw developed specifically for timber-to-steel joints in Mass Timber systems, responds to this requirement through a dedicated geometry: the enlarged pan head ensures stable bearing against the plate, while the fine-pitch thread increases shear and tensile resistance without overstressing the underhead zone.

These aspects are far from secondary when it comes to sustainable architecture. A properly designed connection reduces the risk of premature failure, the need for reinforcement and invasive maintenance, contributing to the building’s durability and to the long-term stability of its performance.

Seismic resilience and sustainable choices as a common denominator

The new parliamentary buildings bring together two key concepts in the New Zealand construction landscape: sustainable architecture and expertise in earthquake-resistant construction.

The experience of New Zealand engineers in the seismic design of timber structures is recognised worldwide, drawing on well-established solutions for seismic resilience, including base isolators and viscous shock-absorbing dampers.
This expertise informed the entire design process, also addressing the additional complexity of linking the new buildings to the existing parliamentary structure.

The old and new parliament buildings will in fact be connected by a suspended bridge, which must perform effectively during both minor seismic events and earthquakes of a greater magnitude. This approach ensures high-level seismic performance, in compliance with Importance Level 4 (IL4).

Sustainable architecture as a system, not a single element

The New Zealand Parliamentary Buildings Project demonstrates that sustainability in architecture is achieved through the successful integration of materials, processes and technical solutions.
The choice of Mass Timber, the Design for Assembly approach, on-site timber protection and the reliability of structural connections all contribute to reducing the building's real environmental impact.

Rothoblaas supports this approach to design with products, advanced technical expertise and certifications. Explore some examples here, and get in touch with our consultants for tailored support.