Respecting climate & culture

A timber research facility has been constructed in Rotorua, New Zealand which combines a net zero design showcasing timber’s potential with a high degree of local cultural sensitivity. Jack Wooler reports

The fritted pattern of the glazing between the timber structure of Te Whare Nui o Tuteata – otherwise known as Scion Timber Innovation Hub in Rotorua – depicts the surrounding forests that inspired its design. And similarly the building is intended to act as a bastion that proudly displays what timber is capable of.

Located on the edge of the redwood treeline of Whakarewarewa Forest Park, the project, commissioned by New Zealand’s Government, brings much of the institute’s workforce, previously siloed in smaller buildings dotted around the Te Papa Tipu Innovation Park, together in one ‘innovation hub.’ It also provides a new arrival point for the campus, strengthening the institute’s public face.

Now, as visitors encounter the building at the entrance to the campus, they are presented with an impressive, three level, 1800 m2 timber diagrid structure of laminated veneer lumber.

Having created a building whose timber structure is easily read as such from outside, the architects hope the strong expression of the material’s use will inspire building designers of the future, showing them how timber framed buildings on this scale can provide a viable alternative to their steel and concrete counterparts. However it’s also aimed at potentially achieving even more, providing an exemplar of working within the constraints of a zero-carbon future.

Not just an homage to timber, however, the building also respects the Māori culture of Rotorua, resulting in a form rich with symbolism. Its name, Te Whare Nui o Tuteata, pays homage to the Tuteata, from whom the region’s three Hapu (Māori tribes) descend.

The brief

The brief given to two practices working in collaboration, RTA Studio and Irving Smith Architects, was to reimagine the headquarters, creating a ‘new front door’ for Scion, and showcase timber technology and the institute’s work. However the design also needed to “engage with the forest, acknowledge the cultural significance of the region, and to create a contemporary workplace environment that brings Scion together,” said the architects. This meant employees, the public and also its commercial partners.

According to Dr Jeremy Smith, design director at Irving Smith Architects and an associate professor at the University of Auckland, as well as fulfilling this brief, the building has already had a positive reception following its 2021 completion. He says this is “a recognition of the outward thinking to the building and its contribution and invitation to the community.” He says that in so doing, the building provides “a real-life experience of science.”

Smith explains that, as a new insertion within an ageing existing campus, the building achieves a lot in improving the sprawling site’s ‘key adjacencies.’ The architect says the careful building placement “consolidates and links the campus” by relocating an existing laboratory block to “enable the new building platform,” and it also “boldly connects” the new hub to two existing blocks (including one of laboratories). This also has the benefit of “triggering public Health & Safety control points.”

He tells me that this placement also capitalises on the opportunity to shift the campus’ entrance from the former “confused” approach from Sala Street, to a more scenic alternative through towering redwoods (along Titokorangi Drive). Scion’s new hub slowly reveals itself and is only fully viewed once visitors pass through the entry gates.

Three peaks

Forming a trio of ‘peaks’ in glulam timber, the entranceway has been designed to reference the three Hapu (Māori tribes) in the region, “standing proud and tall” as users enter the building, says Smith.

Visitors passing beneath this portal are greeted by a triple-height atrium, containing a curated exhibition of wood fibre technology.

Just as on the approach from the road, once within the building, it reveals its nature slowly, “like a forest,” says the architect. Natural light penetrates deep inside thanks to the extensive glazing, continually changing throughout the day as if “under a tree canopy.”

Fully exposed and immediately obvious inside is the structural diagrid, which rises three storeys to form the skeleton of the building. Made of high-performance LVT (Laminated Veneer Lumber), the skeleton features dovetail node joints which have been slotted and glued together.

The triple-height atrium is topped by a spectacular custom-designed wooden ceiling (reportedly inspired by the genomic structure of the radiata pine used for the building’s frame). According to the architects, the timber battens and plywood panels in subtle tones are intended to depict the ‘barcoding’ effect that comes from the plant’s DNA. The arrangement of atrium ceiling lights is intended to represent the Matariki star cluster, a much-loved astrological feature in New Zealand which is described as ‘mother Matariki and her six daughters,’ the stars’ re-appearance signalling the beginning of the Māori New Year.

The ground floor is open to the public, with a cafe accessible to all. However the spaces this atrium sits between on the upper floors – where the collaborative scientific work spaces are located – are restricted, with secure access at the stairways and lifts.

Even from downstairs, however, research work can be seen being carried out on the upper floors, bringing a lively bustle to the open plan-offices and collaboration spaces. However separation is provided from the surrounding noise thanks to private spaces and acoustically treated rooms.

To achieve this, an innovative CLT acoustic partitioning system was developed for the meeting room spaces, further showcasing the use of engineered timber as a flexible and versatile material.

Expressing timber values

It is obvious from only a brief glance at the building that its predominant material is timber. This is transparently obvious in the interior – primarily in the open mesh of the diagrid – but viewable from the extensive glazing of the external envelope.

Other key uses of timber in the building include a lightweight composite CLT and LVL floor system (timber at ground level), exposed and cantilevered CLT stair elements within the three-level central atrium, overlay acoustic floors to promote acoustics and building servicing, and a simple ‘gang nail’ truss roof structure.

Timber was also used in many other parts of the interior, with the structural Radiata Pine being paired with locally grown exotic hardwoods like Tasmanian Blackwood for handrails and ‘leaners,’ along with Victorian Ash for screening elements. Radiata Pine is also used in the reception counter, with plywood panels CNC machined, layer by layer, to achieve an organically curving wood form – reminiscent of a fallen log in the forest. Even meeting room doors are made from CLT, routed with a simple pattern to reference the geometry of the diagrid structure.

According to the architects, such a broad expression of the material was key to the design of the project, with both the client and designers keen to “reveal its natural aspects,” and maximise the material’s inherent “visually warm and inviting nature.”

The raised acoustic floor system, for instance, achieves this by allowing flexible running of surfaces through the floor space, meaning that the CLT and LVL floor structure could be exposed and showcased.

Challenging structural stereotypes

Perhaps the most important aspect of the timber design for the project, says Smith, is how the three-storey engineered timber diagrid “challenges stereotypes of timber structural buildings.”

He says it “legibly demonstrates that timber structural buildings do not need to be designed like steel and concrete buildings, but instead can act more like trees where strength follows the continuous grain of the wood,” explains Dr Smith. “With this simple shift in thinking,” he continues, “the structural size of the timber has been reduced by around three quarters.”

As a further example of innovation, the timber structural nodes not only transfer loads and hold a ‘seismic fuse’ which, if an earthquake occurs, will yield to be replaced afterwards.

Besides cost efficiencies, the smaller nature of the structure also means that the timber was easier to handle, transport, and sustainably resource, and ultimately change or re-use.

Prefabrication was reportedly key to the realisation of this project, with the LVL diagrids assembled from a limited number of repeating, multi storey components, to maximise the potential of repetition, and simplify both fabrication and site erection.

In the future, Smith hopes that such techniques will allow an increasing number of buildings to be built using the material, which he says is useful not just to a small, isolated country like New Zealand – where new machines and construction materials like steel and concrete usually come via boat – but to larger countries where efforts to store carbon in buildings often is thought of in larger and larger components, befitting the ‘mass’ timber name.

He sums up the approach: “Sustainability does not mean more, it means less.”

Meeting net zero

While the building isn’t entirely constructed of timber – it has a concrete ring beam foundation for geothermal reasons, and a perimeter curtain wall glazing system – the building was nonetheless carbon neutral “from day one,” say the architects.

In order to achieve this, besides the inherent benefits of the use of timber itself, the building utilises low energy lighting and low water usage sanitary fittings, which, together with the mixed mode ventilation system, means the building has a predicted energy usage of 80 kWh/m2/year, and water usage of 12.6 litres per person per day. It also has a 34% reduction in ‘operational impacts’ when compared to equivalent ‘baseline’ reference building.

In order to ensure this level of sustainability, the team employed the ETool system to measure their embodied carbon – how much carbon is released, and how much is stored in the making of the building. The building achieved zero embodied carbon at the end of construction, storing as much carbon as has been released through the raw material mining, manufacturing, transportation, and installation, and without any offsetting of carbon credits.

According to the architects, whole life carbon usage of the building (over the next 60 years) will be around two thirds of those of current 2020 RIBA reference building targets The building sequesters 530,488 kg of carbon, or around 300 kg of carbon per square metre, and stores approximately 415 tonnes of ‘carbon dioxide equivalent’ (C02-e) in just its primary timber structure for the life of the building – the latter being comparable to the emissions of 160 flights around the world.

As such, Smith hails the building as “ahead of its time,” noting that the 454 m3 of structural timber used is regrown “every 35 minutes” in New Zealand.

Looking forwards

Looking back on the project, Smith reflects that Te Whare Nui o Tuteata represents “more than 10 years of advancement and sophistication in the way timber structural buildings are not just put together but conceptualised.”

He hails the project as well as bringing benefits to future generations, it “encourages others to think harder about what timber is good at, and how timber buildings might be better prefabricated and pieced together.” Smith adds that being such a timber showcase makes it a “globally significant scientific demonstration of how we might build tomorrow.” He says it’s a “real prototype, rather than just a possibility,” as New Zealand works towards zero carbon in 2050.