The practice of gluing pieces of timber together, whether for decorative or functional purposes, has been with us for thousands of years. However, the concept of gluing relatively thin layers of timber together to form a structural member is a development of the twentieth century. These structural members are referred to as `glulam’.
Glulam originated in Germany at the turn of the century and was introduced into North America in the late 1930’s. It reached Australia in the early 1950’s.
The introduction of glulam to Australia can be largely attributed to the motivational drive of the former CSIRO Division of Forest Products. Within the CSIRO there existed a strong commitment to change attitudes towards timber, from its popular image as a craft material, largely used in cottage construction, to that of a reliable structural engineering material able to compete with others, particularly steel. CSIRO endeavoured to foster interest in glulam, hoping this would stimulate demand and create new market opportunities for the utilisation of timber, by extending its aesthetic and structural qualities beyond that possible with sawn timber.
The early development of glulam in Australia focused on the manufacture of glulam members made to customer specifications for commercial and institutional building projects and the like. Generally the shape of the glulam members were of simple curve and portal form. The timber resource for early glulam fabrication was primarly hardwoods, e.g. jarrah, brushbox, and ash type eucalypts, whereas in Europe and North America the primary resource was softwoods.
There was strong initial enthusiasm towards creating new market opportunities with glulam, however this waned when the product came into disrepute with architects and engineers as the result of the local industry’s lack of experience with quality control processes. Anecdotal evidence suggests the primary concerns were about the delamination of members, particularly those bonded with aminoplastic adhesives.
This situation was not unique to Australia, as similar problems had been experienced in North America. In Germany, the concern for product safety and reliability resulted in the German Government instituting a system of licensing manufacturers of glulam and thus controlling product quality. This system of licensing still exists today.
The declining interest in glulam can also be attributed to the fact that manufacturers lacked the sophistication to provide design, fabrication and construction services similar to those provided by the steel industry. This proved a major obstacle to the use of glulam outside the residential building market and in an attempt to overcome this, CISRO ran a timber engineering design service.
Furthermore, it was not until the early 1970’s that appropriate Standards for timber design and glulam manufacture was completed. The conversion from imperial units to metric units had just occurred and the stress grading system had been changed. There was a large number of conflicting Standards dealing with timber grading, testing and design and there was a general perception among designers that working with timber was too difficult. They lost interest in designing in timber, let alone in glulam.
The 1970’s was a period of action. The members of the former Radiata Pine Association of Australia (RPAA) were confident about the potential for radiata pine glulam and they produced a number of publications covering industry standardised sizes and grades of glulam as an aid to timber design. These were an attempt to provide the information needed by architects, engineers and builders.
Using these publications, customers could choose from a range of glulam members sizes. With the many cross sectional sizes, grade lay-ups, cambers and surface finishes on offer, it was possible to supply some two thousand combinations and permutations of glulam members. Depending on the combinations ordered, the supply of custom made-to-order glulam often resulted in long lead times for delivery. These were unacceptable to the residential building industry, which is accustomed to off-the-shelf supply. Project builders in the commercial market, who were accustomed to lead times for the custom made and fabricated components, more often than not, expected to be quoted for both supply and construction.
As a result, some pine glulam manufacturers rationalised the supply by limiting the range of glulam sections to stock sizes. This improved the unit costs and reduced lead times from weeks down to virtually immediate delivery, while providing the market with an acceptable range of member sizes, suitable for the needs of the residential and light commercial structures. This rationalisation suited the wholesale distribution merchandising operations of the manufacturers. In North America, glulam manufacturers had taken similar decisions to rationalise sizes and grades, and produce stock size sections.
From the 1970’s, the trend has continued towards supplying stock glulam in both softwood and hardwood for the residential market, in lieu of custom made glulam.
In the 1970’s, there was a significant re-emergence of hardwood glulam manufacturers. This can be attributed to the increase in knowledge and experience in gluing hardwoods, and the increasing need to better utilise the available native hardwood resource.
Since the late 1980’s, the enthusiasm for the use of glulam has significantly increased. This can be attributed to a number of elements:
- Increased awareness by manufacturers of the needs of designers. Many manufacturers have been producing design tables and charts.
- Increased promotional activities by the manufacturers to make designers aware of products, and their capabilities and availabilities.
- Increased sophistication of manufacturers in establishing capabilities to provide complete design, supply, fabrication and construction services to project builders in the commercial building market.
- Increased awareness and emphasis placed on the need for quality assurance schemes.
In Australia, however, the use of glulam has never reached the same level as in Europe and North America. The annual glulam consumption in Australia is approximately 30,000 cubic metres, which is 0.6% of total timber consumption. When compared to Europe and North America, annual consumption on a per capita pro-rata basis suggests the potential market for glulam is between 0.9% to 1.6% of the total sawn timber production, or 35,000 to 65,000 cubic metres.
There are a number of reasons why glulam has not yet achieved the same levels of usage in Australia as overseas:
- In Europe and to a lesser extent in North America, there exists a strong cultural attitude towards a preference for timber in all its forms in both structural and non-structural uses. In Europe, timber engineering is not only taught at tertiary institutions, but is offered to students who choose to specialise in timber production and structural design. Australia offers neither this cultural attitude towards timber nor this emphasis on timber at tertiary institutions.
- Climatic conditions in many parts of Europe and North America mean that many sporting activities are confined to indoors and there is a market for glulam as the structural material for these structures. By comparison, Australia’s climatic conditions tend to favour outdoor sporting activities, hence, there is not the market opportunity for sheltered structures.
- Glulam manufacturers in Europe and, to a lesser extent, in North America, offer complete design, supply, fabrication and construction services to project builders in the commercial market.
- Population densities in both Europe and North America are more conducive to supporting large capital intensive glulam manufacturing operations. By comparison, Australia’s relatively small and geographically spread population has tended to spawn small glulam manufacturers, whose operations are geared to the needs of the local residential market.
- Europe and North America have well established and recognised third party certification schemes which are promoted to engender customer confidence in both the image of the industry and the quality of glulam. These have contributed to the acceptance of glulam. No similar scheme existed in Australia prior to the establishment of the GLTAA.
The industry has recognised and addressed the above issues and is now well positioned to see the realisation of its goal – the increased usage of glulam in Australia.