By Sean Cavan
The leaky building syndrome is in part about the building industry admitting its mistakes and overcoming them. The laminated timber industry was in a similar position prior to the Sydney 2000 Olympics. Hunter Laminates of Nelson received a very large order to supply laminated timber beams for the Sydney Olympics. These beams form the main structure of a building that is 270 metres long, 76 metres across and with a 90 metre diameter dome.
The initial batch of laminated beams were manufactured according to the accepted methodology of the time, however, when they were tested for strength and quality, they failed. The strength requirement was F11 which is a strength and stiffness grading for glue laminated timber?about 50% higher than No.1 framing timber. This failure resulted in the company going into receivership.
As no other company in the Southern Hemisphere had the capacity to produce the volume of timber required in the time available, the client (the Olympic Organising Committee) worked with the receivers, the company and Forest Research Institute to overcome the problems. Radical changes were made in the process of timber selection, laminate manufacture, finger jointing and quality assurance.
The end result of this work was that 85% of the beams were supplied to the project and within the original timeframe. The final product achieved F14 and F17 strengths which were substantially stronger than the original F11 specified.
As a consequence of the initial failure and the subsequent improvement work that was carried out after the receivership, the rules describing how laminated timber is constructed have been modified. These reflect the new methods developed in the re-supply contract. These methods have been implemented throughout the industry. The result is a better and more reliable product.
The construction industry has been shown to have used poor systems, materials and methodology which has resulted in widespread weathertightness failures. To cure these ills, like the laminated timber industry, changes to accepted and established practices were necessary. Whilst our understanding of weathertightness science is not complete, the major challenge is now with implementation. A key component is the adoption of simple but effective quality assurance programs.
We also need to ensure the principles and lessons learned from failures in Canada and New Zealand are applied in the design and construction of new buildings. Understanding how buildings work is a key component to ensuring a quality product. Unlike laminated timber beams, the construction of buildings, especially those that are more complex, involves a degree of one-off design and on-site decisions. The combination of quality assurance measures and good understanding by those who design and construct buildings is necessary.
The aim is to eliminate leaky buildings so that future generations of building owners do not have to endure similar problems. The building industry needs to measure its outcomes. It needs to learn from its failures, find solutions and implement these. The experience of the laminated timber industry is a graphic example of what can be learned from failure.
Sean has had 30 years in many areas of the construction industry. He has experience in design, detailing, surveying and site supervision of high rise construction, large civil projects, industrial manufacturing projects and urban subdivisions. He has spent time in the timber truss industry designing and detailing roofs and carrying out software support. He has also run a large timber glue manufacturing plant and his recent involvement has been as a contract manager for a residential company.