Consistency, quality and precision are the three watchwords for the timber treatments industry.
One key development in recent years has been Arch Timber Treatment’s Auto-Treater control system, a computer-based management and automation system designed to give precise control over all aspects of the treatment operation. “This helps our customers [treatment companies] to achieve a more consistent and precise treatment of the timber,” said Arch’s David Law.
This, he explained, is especially useful when you consider that industry standards (BS 8417) now identify the penetration of preservative into the timber to achieve the correct levels of protection. The result of the Arch system, said Law, is that only the correct amount of preservative is used to achieve the necessary protection of the timbers, reducing preservative product wastage and providing a precision controlled result.
Peter Fitzsimons, account manager UK & Ireland, Wolman Division/BASF, added that precise technical specification of treatments is becoming the key focus. “In our opinion, it is of most importance that the suppliers of wood preservatives publicise their recommendations for retentions in the different use classes to make external/independent quality control possible,” he said.
Wolman expects particularly to see a growth in the premium sector where, besides durability, aesthetic aspects are of importance (areas like cladding and decking, for example). “For this sector, with our Pinadur system, we have an alternative against tropical hardwoods or modified timber,” said Fitzsimons.
The formulation of preservatives has also changed in recent years. Apart from some specialist joinery applications, most wood preservatives used on structural or ‘decorative’ timbers today are now water-based. This has been further developed with different colour markers being marketed by different suppliers of constructional double-vacuum treated material. Other formulation innovations continue to take place.
Osmose reports growing use of its MicroPro system that uses micronising technology to grind copper particles so small that they can penetrate into the wood in solid form. This provides a number of benefits that other treatment processes are unable to match, said Osmose Europe’s marketing manager Andy Hodge, including a “lighter, brighter more natural looking material” with the opportunity to develop “enhanced colouring systems”.
He also said the technology allows users to get different benefits out of wood they wouldn’t achieve with conventional copper-based systems. “One of the things that’s happened in the US is that the micronising technology has dramatically changed the market because of the benefits it brings to the wood. These are manufacturing benefits to the treater and big benefits to the consumer.”
The new generation of timber treatments, said Hodge, also opens the door for using a wider range of metal to wood connectors in construction. “If you are using cladding, decking or timber materials in a landscaping situation you couldn’t just use ordinary external fixings or fasteners with previous generation [solvent heavy] treatments,” said Hodge. “You had to use ones that were coated or you’d get a reaction in the wood to the fasteners. Because, with MicroPro for instance, there is no solvent in the system, the treated wood performs more like it did with earlier CCA-treatments. You don’t get corrosion of metal in the wood, which means you can use standard types – even aluminium.”
Osmose has also been moving into stabilising oils. The company has been working with the American Hardwood Export Council and American tulipwood, which is sold as a natural product. Osmose was technical adviser to the David Adjaye “Sclera” project, a pavilion made of American tulipwood that was on display at the Southbank Centre in last year’s London Design Festival. “We took our stabilising oil, blended in mouldicides and coated the product,” said Law. “Tests showed that using this approach not only made the structure more stable, it held off the greying effect of weathering significantly.”
Many architects favour untreated timber such as oak and cedar externally, for instance for window frames or cladding. But while accepting this has its applications, treatment suppliers offer a word of caution. “All timber species have a sapwood content that is more prone to degradation than its more durable heartwood,” said Arch’s Law. “If untreated timbers are to be used outside, the more resilient species must be used with the sapwood content removed. If sapwood is present, we would still recommend a preservative treatment.”
Peter Fitzsimons agreed: “Don’t overestimate the natural durability,” he said. “In higher risk applications, where higher moisture contents cannot be excluded by design, treated timber may be preferable and give more predictable performance.”
As Law added: “The whole idea of timber preservation is to allow more abundant and easily replenished species to be used with real confidence.
“Utilisation of this combination is a much more sustainable solution, helping softwood forests around the world to be well managed and expand and reduce the use of the scarcer hardwood species.”
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Exterior cladding treated with Osmose’s copper-based MicroPro |
