Production and Use of Laminated Veneer Lumber

A local lifecycle story from the trees in Nelson Forests to the processing at Nelson Pine Industries (and manufacturing at Hunter Laminates) to the remarkably innovative NMIT Arts and Media building designed by Andrew Irving – and what it means for the industry.

Jason Guiver was the General Manager of Hunter Laminates at the time the company manufactured the timber components for the NMIT building; he has most recently worked for NZWood as Technical Manager.

He says that even with this new technology, New Zealand will still be exporting logs. For example in Christchurch, 1,000 commercial buildings will be needed over the next five years. Say 20% of them are built in timber, then that would require 100,000 cubic metres of timber, or 40,000 logs. That’s only 0.3% of NZ’s log exports a year, so we won’t be losing exports of logs, only gaining revenue.

Lees Seymour, the managing director of Nelson Forests Ltd and the chairman of NZ Wood says timber is a great product. It creates lots of jobs, is environmentally friendly, and stores carbon. People are looking for best practice, for environmental sustainability, and a low carbon footprint, and this product delivers on all those issues.

“It’s a fantastic story: not only are we showing the merits of the local region, but the merits of the industry and what it can deliver to New Zealand and the international market.”

Local expertise has developed a world first multi-storey laminated veneer lumber (LVL) building.

“This story is all about “Kiwi can-do” attitudes and expertise: from the trees we grew to the processing at Nelson Pine, to the work at Hunter Laminates to the local architect and building contractors Gibbons, and the client, the Nelson Marlborough Institute of Technology.

This kind of timber building is perfect for rebuilding in Christchurch because it withstands earthquakes to a higher degree, and if it does get damaged it is pretty easy to fix.

It will take time to get this building method established, so there is quite a bit of work going into promoting it to property developers, building owners and construction companies.

At NZ Wood our long-term objective is to get more buildings like this, or similar designs, built, not only in Christchurch, but throughout the country. We have the potential to export this building technology into other earthquake prone areas of the world.

We want people to build based on the knowledge about how sustainable, how environmentally friendly, how much carbon trees store, and how safe these buildings are.

It only took 200 trees to produce the 500 cubic metres of timber and LVL for the building in Nelson. These trees are of higher stiffness than the average radiata pine – that is one of the characteristics about the trees that make this type of application possible. We can enhance the stiffness of the tree by not pruning it. These trees have come from a framing or structural regime.

Although most of our forest is pruned, we have a higher proportion coming through of structural forest to be harvested now.

In Nelson and Marlborough we have 63,000ha of planted area, producing just over a million cubic metres of logs a year. Of this, 70% is sold to domestic customers, and 30% is exported as logs.

Nelson Pine is our major domestic customer, and it makes two main products: medium density fibreboard (MDF) and laminated veneer lumber (LVL).”

Chris Turner, CEO of Nelson Pine Industries explains that after the logs arrive at Nelson Pine Industries, they are debarked, cut to length and then soaked in water at 80c for up to 24 hours. From here the logs are peeled into veneers, dried and graded for strength and appearance.

The veneers are then assembled into LVL (laminated veneer lumber) with the strong veneers on the outside and the lower strength veneers in the centre to form a structural beam with consistent strength and dimensional stability superior to solid wood.

The laminating process is achieved by adding resin to the surface of the veneers and applying heat and pressure through a continuous press to form laminated veneer lumber billets 1.2 metres wide and up to 18 metres in length.

All process waste wood is used to generate heat for the veneer drying.

From here the LVL was shipped to Hunter Laminates in Richmond for fabrication. Here it was re-laminated into larger beams, columns and shear walls.

Hunter Laminates also made Potius flooring panels, which were also dropped into place on the building site. The whole thing was a pre-fabrication process.

Because these buildings can be pre-fabricated, they can be exported. If you were to export a building, there would be 30 times more value by volume in the building as opposed to exporting the logs.

In Europe, the majority of timber buildings are pre-fabricated in Austria, Germany and Switzerland, and shipped by road all around Europe.

In the future LVL exports from NZ are expected to be cost-competitive with other building methods.

Chris says “the Nelson region is a one-stop shop for forest and timber processing facilities. Anything we want to make from timber can be made in this area. It keeps the carbon footprint down, and all we are sending away is a completed item.”

An architectural competition was held for the NMIT arts and media building, and part of the terms of reference was that MAF wanted to build a landmark timber structure. This was won by Irving Smith Jack Architects, and architect Andrew Irving worked on the project.

At that time the Minister was Jim Anderton, and he wanted to encourage the use of timber in commercial construction in New Zealand. As part of the competition MAF provided top-up funding to NMIT of up to $1million for the building.

Next door to the site was another recently completed building of a similar scale which was built in concrete and steel, and this offered opportunities for comparison.

Andrew says “One of our design drivers was, “what do we have to do to win an architectural competition with a wood focus? We worked hand in glove with our engineers Aurecon, who are based in Nelson.

We decided to try and express all the timber components of the building so that you could see them, and understand the way the building works.

This was prior to the Christchurch earthquakes. Aurecon suggested it would be great to design our seismic bracing systems in timber and using technology never tried before in timber: damage avoidance design.

This turned out to be timely. We are able to use structural members that are not increased in size. It’s a very simple system, and after most earthquakes which you could reasonably predict, the building would be structurally undamaged. With some simple repairs to easily replaced components it would be safe to occupy relatively quickly.

The other thing about the building that is new and exciting is that it uses some environmental principles to use as much natural light as possible, natural ventilation and there is an element of passive heating and cooling integral to the building.

At the moment the University of Canterbury and Auckland University in conjunction with GNS are carrying out research on the building. The University of Canterbury is measuring and comparing energy use between the two buildings.

In a combined project Auckland University and GNS are measuring seismicity and things like temperature and humidity. They have about 30 measurement devices assessing how the building moves and deflects, and comparing this to what the engineers expected.

We are extremely proud of the building; it’s the largest building we have completed, and we’ve done it in a way no-one has made a building before.

We see it as the basis for some research and development so we can start building in a more commercial environment. There was a research component to this building, state sponsorship, and it is in a campus environment with no immediate neighbours.

So there are a whole lot of issues we didn’t address. We are now working on a research and design process for a commercial building site in Hereford Street Christchurch, for a building with a predominantly timber structure. This hybrid building incorporates the same damage avoidance design concepts as the NMIT structure. We are hoping it will be completed within 18 months, and our research indicates it is within 5% of the cost of a standard concrete building.

We think this NMIT building will be a launching pad for buildings which incorporate more timber and the damage avoidance design technique and which can be realized economically.

We want to find a way of making a building commercially, which uses this technology and as much timber as practical. This makes the most of the fact that timber is a lightweight structural component, and can enhance seismic performance.

There’s been a lot of interest in this building, and people are looking at ways they might use the technology.

The other thing we are excited about is the arts and media staff at NMIT love the building, and it exceeds their expectations.

One of the reasons is because it is made of wood. There is something about being in a timber building that is slightly unexpected to us, it is an emotive thing, and not about maths. It is great to see that level of user satisfaction.”