Back to our roots

By Lisa Oliver, Senior Project Engineer – Holmes Consulting

With the growing global focus on sustainability and pressure on businesses to reduce their carbon footprint, it should come as no surprise that design consultants are re-evaluating the potential environmental impact of new commercial projects.

With that in mind, there’s a rapid rise in the use of and interest in a material that has been used for millennia: timber.

Many New Zealanders have grown up in timber homes and the abundance of beautiful villas and bungalows makes us stand out from many countries overseas. But, until now, the use of timber in commercial structures has been relatively low. 

That’s changing.

Norway, for example, has set the bar high. The Mjøstårnet building, completed in March this year, is an 18-storey timber building which towers above its surroundings at 85.4m high.

Across the ditch, Brisbane last year welcomed a new feat in timber engineering with its 25 King building in the city’s CBD - a first-of-its-kind, ten-storey building. It houses office spaces and was engineered using cross-laminated timber cladding and flooring.

Here in New Zealand you can expect some exciting developments too. We’re constantly on the look-out for solutions that both minimise environmental outputs and ensure structures last, while meeting the overall brief – whether it’s a brand new building or a heritage restoration project.

Clients and project partners are increasingly open to the use of natural resources in commercial construction and, specifically, timber. In the past, if it was included in commercial structures it was largely down to the aesthetic it provided.

There’s a way to go before we catch up with the likes of Norway, but there are ripe opportunities here for engineers and architects to capitalise on the availability of timber and draw on its functional, cost, and environmental benefits. 

Take the restoration of the Waihinga Martinborough Community Centre: this 106-year-old masonry town hall was recently transformed into a multi-purpose hub for the local community, however, this was no ordinary restoration project.

The combination of lightweight timber and steel was used to both seismically strengthen the existing building, as well as form the new extension, which is now a striking focal point in the town centre.

There are, of course, a number of factors that come into consideration when selecting the best building material for a project. It must be able to perform well in a range of climates and, in New Zealand’s case, high seismic performance is critical.

In the past, timber was overlooked for the structure of large-scale developments, but that’s changing. One benefit timber has is its ability to withstand certain environments much better than other materials—for example, the warm and humid environments of indoor swimming pool complexes. In both commercial and residential settings, timber is often favoured because of its durability compared to other materials.

A local example showcasing these points is the Wanaka Recreation Centre. Completed last year, the aquatic complex features the extensive use of exposed timber beams, timber panelling, timber ceiling details, as well as a partial timber façade. Where steel elements are used, this is hidden where possible inside the timber to reduce the area for potential corrosion.

More often than not, the way in which timber can be incorporated into a building is by using it in combination with other materials that complement one another. While this can present some challenges, it also offers up solutions for projects with unique structural needs.

As I touched on earlier, in addition to functionality and aesthetic, the climate change movement is driving a resurgence in the use of timber. Increasingly, clients and project leads want to demonstrate innovation and lead the charge with climate-positive behaviour.  

It’s estimated that the construction sector contributes up to 38% of our total global annual greenhouse gas emissions. This makes it imperative for engineers and designers to continually think of smarter ways to offer their clients energy and resource-efficiency in the delivery of their projects.

Thinking about the future—in terms of the residential and commercial developments needed to support New Zealand’s predicted population growth and the role of our industry to ensure these developments are both structurally sound and sustainable—there’s a real opportunity for architects and engineers to push the boundaries of what’s structurally possible with timber.

I noticed during my time living and working in the Netherlands, that the use of timber in commercial structures has been on the rise in European construction. Its use is also on the increase in the United States and Canadian construction markets, where they face similar seismic activity along their respective West Coasts to what we face in New Zealand.

While New Zealand isn’t home to any timber high-rises just yet, we should expect to see more commercial structures featuring a high volume of timber materials over the next decade, as design and construction technologies continue to evolve and drive innovation.

New Zealanders are known for their ingenuity, pioneering innovation and for questioning the status quo, so let’s challenge ourselves to lead the charge when it comes to the use of timber in our design and engineering of commercial structures.

Who knows, we could be breaking records next.

Let’s hope so!

Story by: Lisa Oliver, Senior Project Engineer – Holmes Consulting

Photography by: Jamie Cobel; Andy Spain: Tom Roe