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Construction innovation goes back to basics

It may be a case of necessity being the mother of invention, with forward-thinking New Zealand companies like XLam – of which I am CEO – producing enough specialist CLT (cross laminated timber) out of our Nelson HQ and new Australian plant to service demand throughout the South Pacific. Meanwhile, updates are being made to New Zealand Standard 3602, which dictates the treatment required for timber and wood-based products for use in building and construction, to prevent any repeat of the leaky building disaster in which untreated timber was a culprit.

The inclusion in the proposed new standard of mass timber products such as CLT is an acknowledgement by policymakers of the rise in popularity of this unique construction method. While it’s comparatively new in New Zealand – we are the first manufacturer of CLT in the southern hemisphere – CLT has a global record of quality and reliability, having been widely used in Europe for the past 30 years and more recently in the North American market.

Locally, CLT presents a number of benefits to industry stakeholders looking to use mass timber in construction. The kind we produce, which uses a proprietary treatment process, is better quality than other forms of timber. It creates lighter structures so less labour is required, and construction is faster. Critically, especially in light of the Labour-led Government’s commitment to reducing New Zealand’s carbon emissions, CLT is sustainable, because wood has a total negative carbon footprint. And our rigorous testing programme (fire, acoustic, durability and destruction) enables CLT products to remain above the minimum requirements specified in the Building Code.

Our CLT outperforms conventional framed construction in air tightness, thermal insulation, internal moisture management, acoustic insulation and fire resistance. Its use is especially applicable to single-unit housing and in ‘honeycomb” construction – buildings whose permanent walls can act as the primary support structure and work with the floor and roof to make a lightweight, highly stable and rapidly erected structure. In this building category, apartments, multi-unit housing, hotels, aged care facilities, schools and hospitals are all strong candidates for CLT panels.

There’s no doubt CLT has earned a reputation among private and public developers: we are currently working with Auckland Council and Housing New Zealand on building developments. We have supplied and are supplying CLT to provide more than 500 bedrooms for Housing New Zealand alone. Innovation means even after the lessons of leaky buildings, we don’t need to be afraid of wood, and a vanguard local body is Rotorua Lakes Council, which adopted a Wood First policy and action plan in 2015 to encourage the use of wood products and support the district’s vital wood industry.

A creative build in the Auckland CBD

The tower crane suspended in mid-air over Beach Road in downtown Auckland is the crucial ingredient in building a $40 million, 21-level building on a modest 600 square-mketre site, bordering Anzac Avenue, that is adding 9,500 cubic metres of living space to the city’s student accommodation market.

The project started in late 2017 and will wrap in mid-2019, and the crane, one of a pair on the site, was a creative solution to a complex brief. Its suspension above one of the city’s busiest thoroughfares means contractor Arrow International can work around not only regular traffic but the national cycleway that runs directly past the construction site.

Construction in famously hilly Auckland demands lateral thinking, and the site’s 45-degree angle between Anzac and Beach required, among other things, the creative solution of a prefabricated internal wall system, which means levels can be stacked like Lego pieces. Project director Ross Duxfield says: “The rooms are only seven square metres so you can’t move gib board and timber around. The engineers have overdesigned so we can do away with propping the floors and drop in the walls, build the next floor slab above it and pour it, just build the rooms from the ground up. It’s a quick process because there’s not much left behind. The prefab is a huge benefit.”

The prefabricated material is made of leftover wood chip collected from forestry production, reconstituted and compressed into 7.350m x 2.450m panels at the Laminex factory in Taupo. The panels are then painted, cut and stacked to order by Metra Panel Systems, a Huntly company that has been supplying wall and ceiling panels to the New Zealand construction market for nearly 30 years. 

To learn more about CLT, visit www.xlam.co.nz. For more on the proposed updates to New Zealand Standard 3602 and submission guidelines, click here.
Gary Caulfield is CEO of XLam Limited.
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