Timber construction revolution: embracing wood as a sustainable building material in New Zealand
Written by
11 July 2024
•
6 min read
A significant investment in the wood products sector – with plant upgrades, new technology and automation – has increased the quality and efficiency of supply, making wood the material of choice across the construction industry. To uncover the latest advances in technology, we spoke to Carter Holt Harvey Specification Manager Jonathan Rugg, who shares how the long-term performance of engineered wood products will mean mass-engineered timber becomes a fundamental element within construction projects.
The advantages of using timber over materials like concrete and steel
Apart from the environmental benefits of using products manufactured from renewable plantation pine that sequesters carbon over the design life of the products, timber-based materials enable designers to embrace biophilic design, by showcasing the natural beauty of timber with its character, warmth and tactile qualities.
Timber-based structures also provide a number of opportunities in both form and function through an established supply chain, shares Rugg.
“For instance, Futurebuild Laminated Veneer Lumber (LVL) products have the structural reliability and variability similar to that of steel with some products having a higher strength-to-weight ratio than hot rolled steel sections. The lightweight nature of timber-based solutions often produces systems having a lower weight, reducing seismic loads when compared to steel and concrete based systems.”
Other important features that timber-based solutions offer include a high level of corrosion resistance and, subject to design requirements, a level of inherent fire resistance, where mass timber members char from the outside rather than a sudden loss of strength at high temperatures.
Timber construction also contributes to sustainability and environmental conservation in multiple ways. As well as targeting considerations around operational efficiencies and reducing whole-of-life embodied carbon emissions, wood-based products also act as a carbon store.
Tools that measure environmental sustainability, such as Environmental Product Declarations (EPDs) demonstrate a product’s overall sustainability commitment, including the level to which timber products remain carbon-negative over the design life of the products.
The development of EPDs has added an opportunity for an additional level of rigour and optimisation within timber manufacturing operations.
“One of the major learnings from completing our EPDs was the impact of wood-based products being a carbon store. Further, our residues are used to generate renewable energy for our operations, as well as providing raw material for other forest industry sectors, such as pulp and paper, green energy, or landscaping. This supports advantageous Global Warming Potential values and the reduced energy use off the grid.”
Futurebuild LVL ensures waste, both at the plant and on-site, is kept to a minimum as most of their LVL products are now cut to 100mm increments when ordered through the Residential Design Service (RDS) service.
“It is also important to note that Futurebuild LVL untreated and H1.2 treated products are all ‘Red List Free’ under the Declare label programme as part of the International Living Building Institute. Red List Free Declare labels are now recognised as part of the NZGBC Design and As Built tool Credit 21 Sustainable products, as a level B Eco product.”
The latest advancements in timber technology that are driving its use
Investment in the prefabrication sector has created a significant advancement in timber technology, whereby existing supply chains, like the New Zealand merchant channel, have moved towards offering an increased level of panelisation to their customer base.
“Whilst this is a natural progression, this has extended to include automated panelising lines and the like; it is driving reduced timeframes on-site with completed panels being lifted directly into place at the time of delivery. When combined with innovative products like Ecoply Barrier, close-in of residential structures can be completed in days and weeks, not months, subject to project coordination with other products and systems. This also limits the amount of waste procured both on-site and in the factory.”
In North America and Europe, legislation incentivises the use of renewable and carbon-sequestering products such as mass-engineered timber. In France, for example, 50% of the materials in new public buildings must come from either timber or other certified sustainable materials.
“Here in New Zealand, we have a perfect opportunity to lead the world in this area. I can see a time soon where mass timber will become a mainstay and be front of mind for Architects and Designers wanting a sustainable, reliable and durable solution.”
The advantages of designing and building with timber
For architects and designers, the flexibility and low carbon footprint of timber allows freedom around product selection and caters for the adoption of biophilic design principles. It can also achieve relatively long spans with Futurebuild LVL, which means it can be designed to replace equivalent spanning steel sections with some LVL products having a superior strength-to-weight ratio when compared to hot rolled steel sections.
For builders, engineered wood products like Futurebuild LVL hyJOIST are an efficient and easy product to work with.
“It is lightweight and easy to cut, it can require less midspan blocking and remove the need for additional supporting beams and closing joist spacings. So, the time taken to install a midfloor is substantially reduced compared to sawn timber. hyJOIST also allows for ease of installation of services, for example, plumbing and ventilation ducts, possibly reducing the need for expensive dropped ceilings and bulkheads.”
Since the early 2000s, Carter Holt Harvey has offered a suite of software and services to support the growth and optimisation of engineered wood products in the New Zealand market.
“Software solutions include applications for architects and builders like designIT for houses, software for engineers, computeIT suite, and apps for builders on the go to support installation of Futurebuild LVL products as well as Ecoply Barrier and Shadowclad, all of which are freely available for download at www.chhsoftware.co.nz and www.chhply.co.nz.”
Futurebuild LVL offers services to support the specification of engineered wood products in both the residential and non-residential sectors.
“We encourage architects to use our free Residential Design Service (RDS) where we will design and detail up the mid-floor to provide the best solution across our range of products, including an Environmental Impact Statement, detailing the GWP of the products specified. There is also comprehensive technical and software support for all building professionals including Architects and Engineers.”
Explore timber building products from Carter Holt Harvey