Sophisticated timber product is challenging the dominance of steel and concrete in Australian developments. By Donyale Harrison.
There are two types of technological revolution. The first is all-changing, such as the advent of the smartphone, which has seen the landline, fax and cheating-free pub trivia all but disappear, among its many impacts. The second is all-improving, like kitchen whitegoods. Fridges, dishwashers and ovens have expanded the range of foods we cook and how we cook them, but they haven’t wiped out whole industries within a decade. (Even canned tongue still exists, despite it being 70 years since there was an excuse for it.)
This distinction is important when it comes to engineered timber’s revolution in timber construction, as it definitely sits in the all-improving category. Engineered timber has expanded the scope of what can be built with timber, acting as a complement to, rather than working in competition to, lightweight timber framing.
The strength, reliability, predictability and adaptability of engineered timber combine to make it the ideal material for projects that need to manage time, costs, difficult access, difficult foundations or environmental requirements. And its ability to hybridise neatly with traditional lightweight framing, or even steel frames, further expands the projects on which timber can be used.
From high-rise buildings to foolproof flooring, engineered timber is a game changer. But where once Australia was the leading adopter of new engineered timber construction technologies, we’ve slipped behind Europe and the US over the past few years. A lack of understanding about the materials among designers and councils that approve (and commission) projects is partly to blame, mixed with difficulties finding builders, architects and tradespeople experienced in using them. But these problems are disappearing, thanks to the hard work of some of Australia’s leading engineered timber companies.
More than just wood
Engineered wood product (EWP) is the industry term for a set of composite wood products made from binding together veneers, boards, fibres and even particles of wood. It relies on quality adhesives and delivers a product that is stronger than the sawnwood alternative and can usually make use of more of the felled tree than the sawnwood option.
While EWP covers everything from MDF and plywood to glulam and CLT, ‘engineered timber’ is often used as a group term for the three key laminated timber types used in construction: glued laminated timber (glulam or GLT), laminated veneer lumber (LVL) and cross-laminated timber (CLT). Each has its different construction process and qualities, but all offer exciting new possibilities for construction and design.
The key term is ‘engineered’. Unlike sawnwoods, which aren’t just variable according to species but also log-by-log according to location, drought, flood and other climate impacts, engineered timbers take a naturally variable product and make it highly consistent in sizing, quality and performance. Every panel, beam and joist will perform to the specifications given. A raft of quality control processes that begin with timber selection and end in final inspections as the item finishes production ensures reliability.
Engineered timber was developed mid-last century, but first came onto the Australian market when the South Australian Timber Corporation (SATCO) introduced LVL in the late 1980s. This was back in the days when governments funded research and innovation, and SATCO was a key driver of progress in the industry. They found a steady partner in Dindas Australia, and over the next 10 years, LVL began to establish itself in the market.
Glulam was the next cab off the rank, with Tilling Timber an early innovator. It began as a response to sourcing difficulties in the mid-1990s. “We were one of the country’s largest importers of Douglas Fir, a softwood that was used extensively for timber framing due to its ease of use and quality,” says Craig Kay, engineering manager, Tilling Timber. “In 1991, 535,000m3 of North American Douglas Fir was imported into Australia, but by 1995, that figure had reduced to 272,300m3”
Plantation softwood had pushed both green hardwood house frames and Douglas fir from the marketplace, but the product was less strong than its predecessors and so required more support and couldn’t manage large spans.
“Norm and Judy Tilling recognised that the emerging technology of EWP not only had the potential to replace large-section solid sawn timber but also provided a superior product that would expand the options for the use of wood-based product,” says Kay. “In 1995, they recruited engineers to their staff to develop a range of EWP for the Australian market. Later that year, the first I-joists and LVL were added to the existing glulam range to create a comprehensive EWP offering.”
Other manufacturers followed, from the extensive offerings of Hyne Timber to specialist firms such as Merriwa Timbers.
The newcomer is CLT, which has been imported, mostly from Europe and New Zealand, until the opening of XLam Australia earlier this year.
Each product comes with a price premium: LVL costs more than sawnwood, CLT costs more than LVL and glulam can be costlier again. But that cost comes with multiple benefits. As Leon Quinn, national sales and marketing manager Tilling Timber, puts it: “Engineered wood products are lighter, stronger and more consistent, and have opened up many more design possibilities for Australian builders. They can create larger homes with greater open living spaces.”
Making timber smarter
The different manufacturing processes behind engineered timbers help to illustrate the different costs, qualities and uses of the finished product.
LVL is made up of thin wood veneers (softwood and hardwood) that are layered with the grains matching and bonded together using heat and glue to form a large billet. The veneers can be all the one type of timber, or a carefully selected set to incorporate different qualities, depending on the required use of the final product.
Particular ‘recipes’ for the timbers used in LVL can deliver very different results.
Billets come in a range of thicknesses (most in the 28-75mm range), generally as beams from about 90mm to 600mm depth, plus slab of 1200mm, which can be ripped for intermediate widths, of, say 800mm (and a good building design will include a use for the remaining 400mm).
These can be used directly as joists or beams, or manufactured into columns, floor plates, panels, box beams and other common building elements.
Glulam has a series of timber laminates bonded together along the grain. It allows you to produce much stronger and longer pieces than would be possible from the original timber, which can be curved or shaped at the customer’s request. Extremely beautiful and unexpected lines can be produced, but the product’s main value is its very high strength-to-weight ratio.
The laminates can be constructed to have different strengths in different parts of the beam, or include reinforcing elements as required. Because it is strong and long, with a high degree of dimensional stability, glulam is often used for structural beams.
CLT is made of layers of sawnwood timber ‘lamellas’ that are glued together with the grain shifted 90° between each layer, and then pressed until the glue is set. The outer CLT layers always run lengthways, for maximum strength.
The process essentially forms a large timber panel that can be used in the same way as a concrete panel, but is much lighter and easier to transport and move into place as a floorplate, roof panel or wall panel on site.
CLT panels can be supplied as is, or with anything from openings for windows and doors to actual windows, doors, insulation, even painting and tiling in place, ready to be craned into position. Yes, that does require very careful transport and craneage, but the high levels of finish that can be put onto a panel mean that build times with CLT can be measured in weeks – or days.
Each product starts with wood selection, and it’s an area where manufacturers are rightly a little obsessive. “We produce a number of different grades of beams and LGL [Hyne Timber’s glulam brand] from pine sourced from our own mill at Tuan,” says John Hesse, glulam sales manager at Hyne Timber. “We also produce beams made from local Southeast Queensland Hardwoods and Victorian Ash as well. The major benefit of using timber from our own mill is that we grade each individual piece of timber. This allows us to select timber that has the correct section properties required to meet the different grades of beams we offer. The outcome of this is a consistently high-quality product.”
Engineered timber also uses more of the tree in its manufacture. “We can get a higher recovery from timber with our process,” says Mark Umanski, divisional manager at Merriwa Timbers. “To manufacture a beam from a sawn log, it’s difficult to get the larger end sections. However with our glulam product we can utilise all sizes of timber through optimising, finger jointing and cross laminating. This also ensures we achieve the strength rating required.”
Qualities and quibbles
To go back to the opening metaphor, like a good oven, engineered timber is a fine thing in itself, but it’s only as useful as the people working with it. This is the area where opportunity for growth abounds.
Engineered timber’s strength allows for longer spans, fewer supporting members and more certainty in large designs. “Through our process we are able to remove the defects that occur naturally within traditional sawnwood that reduce the structural strength and lifespan,” Umanski says. “We also do quality testing of our finger joints and beams consistently to ensure the required strength rating.”
It’s also lighter than sawnwood and lighter by far than concrete and steel, which means much less in the way of foundations and the potential to build on poorer sites without spending a fortune on ground works.
More importantly, the predictability of engineered timber elements means they can be specified and then constructed offsite and delivered ready to install, whether as beams and joists, larger components and cassettes, or fully assembled panels. Even when used as part of a hybrid structure, the certainty of the product dimensions means that each piece will be the right size, go up quickly, and then do exactly what it’s meant to do.
Accordingly, the significant differences in construction time and labour requirements make engineered timber ideal for multi-residential builds, public housing, educational campuses and public facilities, mid-rise and even high-rise buildings. The Cube Building at Banyan Wharf in London used a hybrid steel/CLT structure and was assembled by just five men. In 30 weeks they erected a 10-storey, 6750m2 building with minimal deliveries and disruption to the neighbouring residents and workers.
In Australia, engineered timbers have also been driving developments forward. Woodleigh School’s new Homesteads development won the 2016 Learning Environments Australasia Award for best new construction/major facility. It was fabricated and built by the team at Vicbeam using Hyne product, with the prefabrication for each homestead taking three weeks and being done entirely offsite at Vicbeam’s facility. They cleverly triple laminated the spotted gum posts to achieve the desired 200x200mm specification and created a 7.2m-span butterfly truss using 240x63mm Hyne glulam.
“We’re very proud of that job,” said Shane Morrison from Vicbeam. “The product is excellent to work with, and by using highly skilled fabricators, we have achieved a high level of precision for the project and client.”
The Green, Parkville, was the tallest modern lightweight timber building in Australia when it was built in 2013 and won the Judges’ Innovation award in the 2014 Australian Timber Design Awards. Although it used light timber framing, the prefab flooring cassettes were made using Tilling’s SmartFrame products.
“They’re the most comprehensive range of lightweight building members, and their strength and flexibility make them complement light timber, mass timber and other forms of construction,” says Quinn.
“Our design, prefabrication and delivery for The Green incorporated hundreds of TecBeam and SmartJoist cassettes, delivered in collaboration with Timbertruss Geelong in 2013. We’re very proud of that work.”
The cassettes were manufactured offsite and craned into position, with the walls following immediately. The ability to work without back propping meant that each level was completed in about 11 days, saving a month on the original building program.
This experience is typical, with significant time savings found on most schedules.
“Because timber is more economical, more environmentally sustainable and more flexible during construction, I think it has great appeal,” says Quinn. But there are difficulties. “We still need to improve knowledge across the market about timber’s application, advantages and available technical support. Many engineering and design professionals have had limited exposure to the attributes, advantages and possibilities of timber and EWP design for construction. Designers and engineers are key to timber systems being specified more in larger commercial projects.”
Additionally, many of the biggest timber building projects in the country have used only imported timber products. For LVL and glulam at least, Australian-manufactured product is readily available and of the highest quality. CLT looks set to follow suit.
Some products do require a lead time, as large stocks aren’t held, but that window tends to be around six weeks maximum, as opposed to the typical three months for product coming from Europe or NZ. And the much faster turnaround for replacement product if an accident occurs during delivery or on site means fewer delays on the build.
Getting the word out
The need for education about engineered timber exists at multiple levels. Designers and engineers require more understanding of the materials’ properties, uses and appeal. Builders and clients need a clearer vision of the whole-of-project cost savings (including time), especially given the material costs will usually be higher and sometimes much higher. And, finally, fabricators and builders need more experience working with engineered timbers.
Tilling Timber has been fighting the good fight for over 20 years. “When we first introduced I-Joists and LVL in 1995, the I-Joist especially was an unknown product,” says Kay. “We spent a long time educating people about what it was, what it could be used for and its advantages over large-end-section solid sawn timber.”
He is sympathetic to professionals who find the pace of change confronting. “The ongoing development within EWP has been relatively rapid, with the addition of glueline preservative and the modification of veneer type and placement within the EWP to suit different end use conditions. These are all concepts that require constant re-education of building industry professionals.”
Tilling provides an encyclopaedic level of information to customers for their products (literally: you can request it on a USB card from any of their offices), and backs this up with SmartFrame software and the Design Centre, which provides a broad range of engineering and design services and support.
Hyne Timber has been leading the way when it comes to promoting the possibilities of engineered timber. “We have spent a lot of time educating design professionals and builders that engineered timber is a viable option to steel and concrete in a range of different types of buildings,” says Hesse.
“We do a lot of presentations to groups, as well as visiting individual firms to discuss projects. We’ve also produced a number of case studies and technical data sheets on engineered products.”
That data includes Building Information Modelling (BIM) in Autodesk Revit for Hyne’s range of glulam products. It contains all product details from dimensions, mass and volume, down to the colour and texture, which can be brought into the designer’s 3D model and distributed to other contractors. The predictable quality of the product means this data can be used again and again.
Hesse says, “Interest has been strong and there has been a large number of downloads. The specification of our products has been increasing and BIM has played its part in this.”
Wesbeam is Australia’s only LVL manufacturer, producing in excess of 80,000m3 per year. It has been working to increase fabricator familiarity with their product through hands-on workshops. “We don’t have the next ones scheduled yet,” says Dr David Bylund, architect and team lead at Wesbeam Tall Timber Building Systems, “but we are planning more. Interested parties should contact me [(03) 8340 0405 or firstname.lastname@example.org].”
And then some manufacturers take a more basic but effective path. Merriwa’s glulam beams have a strong following among frame and truss manufacturers and builders, and are sold through major hardware retailers.
Umanski says, “At Merriwa, all our beams are sent out with supporting information to give any customer, regardless of their timber knowledge, the necessary details such as storage and protection. The information is also available from our website. We like to keep our business operations and products simple without over-complicating things.”
Of course, not everything is about spans and quick build times. The consistency of engineered product makes it perfect for products such as floorboards, given it is stable, flexible and resistant to warping and shrinkage. Tasmanian firm Woodsmith has released a six-colour range of Tasmanian Oak engineered flooring, milled from sustainable regrowth eucalypt hardwood.
With a minimal-waste production process, the boards satisfy the green concerns of many Tasmanian consumers, while delivering a tough, consistent product that is easy to install and comes with a lifetime warranty.
Additionally, the boards look terrific. The aesthetics of timber do still matter, even though many structural engineered timber elements end up clad for appearance or fire-safety purposes.
Wesbeam will soon release a new product, e-slab architectural LVL slab. It’s mass timber element that can be used to prefabricate a range of columns, beams, mass floor or wall elements, and the surface has appealed to some designers for what they’ve described as ‘an industrial aesthetic’.
Hyne provides ‘select’ timbers, in addition to its structural range, that are designed for ‘architecturally expressed timber’ – areas where it will show as a hero element in the final fabric of the building. These are chosen prior to manufacture for the best result.
Hesse says, “These are used in buildings where the designer wants the structural elements of the building to have an aesthetic appeal, such as churches, community buildings, aged care facilities, schools and so on. The environmental benefits of timber have also become a major driver in recent times.”
It’s true that the wellness benefits of timber, part of the ‘biophilia’ effect, are increasingly in demand for offices and multi-res builds. But there’s more. Timber represents a carbon store, rather than the large carbon cost of concrete, and many suppliers also have compelling local stories to tell about their impact on the community.
Merriwa Timbers is serious about its good wood tale. “Our main supplier in pine comes from the South Australian region and our hardwood is purchased in Victoria,” says Umanski. But the company’s staff is its real treasure. Merriwa provides integrated employment opportunities for people with disabilities in the region.
Umanski says, “Merriwa is committed to providing an environment that encourages people of all abilities to reach their potential, while delivering quality products and services. By working with Merriwa you are supporting people with disabilities to be the best they can be.”
Like all timbers, engineered timbers are subject to concerns regarding durability and insect attack. The same rules regarding timber usage apply as for sawnwood, and the same solutions: careful selection of species where possible, treatment where that’s not enough.
Glueline treatments are added to the glue that is used to bind veneers together. Scott Connor, EWP product manager at Lonza Wood Protection, explains: “Permatek 100 encaps is our encapsulated bifenthrin formulation that works very well as a glueline insecticide for the control of termites. The encapsulation provides a protective barrier around the bifenthrin chemistry, which gives enhanced user safety. Since the capsule contains the chemistry, if an operator was accidentally exposed to Permatek 100 encaps they wouldn’t come into contact with the bifenthrin molecule. After the LVL billet or plywood panels exit the press, the chemistry is fixed in the resin matrix and the wood fibre.
“Traditional wet chemistry treatments add moisture to engineered wood products, forcing liquid into a dry structural wood product made to precise dimensions. Doing so usually changes the dimensions of the wood product and can in some cases degrade some structural properties. Treating via the glueline offers a thorough treatment that is evenly distributed right throughout the wood product, and this is all done as part of the manufacturing process not as a separate treatment process after manufacture.”
The result is a product with well-distributed protection from termite attack and decay. It enhances the durability of product such as radiata pine to meet H2s in Australia, meaning manufacturers can concentrate on renewable, affordable materials.
Connor says the treatment won’t interfere with the appearance of the timber: “With exposed structural products, the glueline chemistry isn’t noticeable, so doesn’t pose a problem. Where surface chemistry is required, this can be done in a transparent manner allowing for a natural finish.”
Holding it all together
One vital factor that is often overlooked when engineered timber is specified is connectors. “Typically timber structures are governed by the connection details and designers often do not put enough (or any) thought into this,” says Nathan Tapping, product manager Australia-New Zealand for Simpson Strong-Tie Australia.
“It’s common for generic ‘timber structure by others’ to be seen on drawings and this leaves a lot of expectation for the builder to do the right thing.”
Simpson Strong-Tie is one of a handful of major companies supplying connectors for engineered timber, and has a substantial range available for products such as LVL and I-beams. “As new sizes of product become available, it’s a matter of changing tooling to suit, “Tapping says. “Mass timber products such as CLT have required new connectors and fasteners to be developed and our colleagues in America and Europe have been working on this for some time. Panelised construction is also making an influence on the market. Typically, there are fewer types of connectors but an increase in the overall number of connectors used. The entire construction process and workplace safety needs to be considered.” Planning options include hangers that will hold elements in place safely while they are secured, pre-drilling, and even pre-assembly of elements where there is no safe position for a worker to attach panels at that point on site.
Concealed connectors are also available for exposed timber, though there are a few issues Tapping says designers and builders should consider. “A lot of the deemed to satisfy requirements in the NCC rely on plasterboard coverings to achieve fire rating requirements, and you will need to work with the building surveyors to ensure that their inspection criteria are also met.”
Durability is another area of concern. Tapping says, “Australia can be a harsh environment. Not only do we have cyclones and floods but we can also have snow loads and bushfires to contend with. We can also have seismic conditions – though not as severe as New Zealand or parts of the US. It’s a matter of working through the expected loading conditions with your connector supplier. Worldwide, there is a push for more resilient structures so that after a major event the community can get functioning again quickly. Australia also has hardwood timbers available that are significantly stronger than in America or Europe.”
Interviewing people for this story, their passion for the product is apparent. Many admire the quality of each other’s work, and all hope for industry changes that will help them deliver even better results.
Many also have the same complaints. “I wish designers and builders would engage with a manufacturer early in the design process,” says Hesse, echoing several colleagues. “This could save a lot of time and effort being wasted by the designer or builder on unviable projects.”
Tapping has a related goal: “There is a lot of opportunity for more hybrid-type construction to take advantage of different building materials’ properties. It is a matter of working with the design team to optimise designs.”
Most also spoke of the ability of the customer to influence them strongly in this growing field. Quinn says, “We are heavily customer focused, and pride ourselves on being responsive and innovative. Our new Design Centre Portal came out of customer feedback and has created an information exchange with our customers to help them grow their businesses.”
Bylund is even more straightforward: “If you want a product we don’t produce yet, talk to us. If you want enough of it, we’ll make it.”
Despite still having some teething difficulties, the sector is optimistic. Wesbeam has multiple tall timber projects being negotiated, and sales are strong for the manufacturers and importers.
“There’s great interest from overseas manufacturers in Australia,” says Hesse, “and a number of local manufacturers are developing their own solutions. I think this competition will only increase the acceptance of engineered timber in the market place.”
For more details, visit www.hyne.com.au, www.lonzawoodprotection.com/apac, www.merriwa.org.au, www.strongtie.com.au, www.tilling.com.au, vicbeam.com.au, wearewoodsmith.com.au, wesbeam.com or www.xlam.co.nz