Summary
• The EU Biocidal Products Directive will require the supply of extensive product data.
• Arch’s Auto-Treater system gives precise control over treatment operation.
• Osmose reports growing use of its MicroPro system.
• Wolman says its Pinadur system provides an alternative to tropical and modified timber.

“Preservatives make timber last longer,” says David Law, marketing services manager at Arch Timber Protection.

While this might sound simplistic, today’s preservation products are anything but: with precision, consistency and quality of treatment key priorities, suppliers are having to up the ante with their solutions to maintain specifiers’ and users’ confidence.

One thing driving the ongoing technical development is increased legislative demands. More rigorous test requirements are coming through in British Standards which are expected to raise the bar for gaining approval of preservative products; this, in turn, will help to ensure products are actually fit for purpose. Meanwhile, the phasing in of the EU Biocidal Products Directive (BPD) means treatment providers will have to supply extensive data and reapprove every product they sell in every country in Europe. It might sound onerous, but Mr Law believes it can only be a good thing. “It reassures specifiers and users on safety of products,” he said.

One key development in recent years has been Arch’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 Mr Law.

This, he explained, is especially useful when you consider that industry standards (BS 8417) also now identify the penetration of preservative into the timber to help achieve the correct levels of protection. The result, said Mr 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.

Use Classes

Use Classes, introduced under BS EN 335-1, identify the eventual application of the timbers and therefore trigger the correct level of preservative protection applied by timber treatment companies. The greater the risk of attack by wood destroying organisms, the higher the Use Class required, and a raised level of preservative protection is increasingly leading to the use of high-pressure treatments.

Peter Fitzsimons, account manager UK & Ireland, Wolman Division/BASF, believes that the quality of the treatment is increasingly becoming the key focus. “In our opinion, it is of the utmost 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 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 to tropical hardwoods or modified timber,” said Mr Fitzsimons.

Water-based formulations

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, such as cladding) are now water based. This has been further developed with varying colour markers being marketed by different suppliers of constructional double vacuum-treated material.

“Our customer base is now almost exclusively on water-based products like Arch’s VACSOL range, primarily for operational benefits,” said David Law. “We use the most modern and highly effective ingredients so that lower levels/lower uptakes can be employed: it makes for faster drying and faster turnaround.”

Other formulation innovations continue to take place. Osmose reports growing use of its MicroPro system which 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 to MicroPro technology treated products that other treatment processes are unable to match, said Osmose Europe’s marketing director Andy Hodge, including a “lighter, brighter more natural looking material” with the opportunity to develop “enhanced colouring systems”.

The environmental angle for MicroPro has been a big story in the US with the likes of DIY retail giant Home Depot. Osmose micronised copper technology has been recognised by the international standards accreditation body Scientific Certification Systems as an “environmentally preferred product” – the first wood preservative system to have done so.

“The European systems are slightly different,” said Mr Hodge. “What we’re doing over here is manufacturing everything to ISO 14001, but we are also looking at finding some European schemes to link to. But we are still using the US status in our marketing material. It does have an environmental seal of approval to it.”

There’s also another benefit – and that’s its weathering properties. “What we’ve found is that this product has very different weathering patterns from existing treated wood. Existing treated wood is quite dark and tends to have light sapwood and darker heartwood, and then when it goes out in situ into the sunlight it starts a process of colouring to grey – and does that in a year. What we’re seeing with MicroPro is that it starts off very light and natural-looking, then when you put a MicroPro-treated product into an application, the colour becomes more vibrant. We call this colour enrichment.”

He said this would be ideal for the playground market and for those retailers who want a point of differentiation in the market place. The system has been introduced alongside Osmose’s established wood preservative technologies, Protim Clearchoice and Osmose Naturewood, and Mr Hodge is keen to point out that it’s an extension to the Osmose brand, not a replacement of an existing product.

Niche product

“We see this as a niche product: it has not been brought in to take over and replace other products, but has been introduced as a result of listening to customers’ comments about what they want – and taking technology forward with a product that addresses specific segments,” he said. But, he admitted, it may not be of interest to everybody. “If you are in a competitive environment or a market where you’re not looking for big innovations, then the standard systems we have will be very acceptable to a lot of businesses,” he said.

Osmose has also been moving into stabilising oils. The company has been working with The American Hardwood Export Council on US tulipwood, so it can be used externally and as a naturally-preserved material. Osmose was technical adviser to the David Adjaye “Sclera” project, a pavilion made of American tulipwood that was on display at the Southbank centre as part of last year’s London Design Festival. “We took our Stabilizing Oil and blended in some mouldicides, and coated the product. Testing we carried out on tulipwood showed that using our Stabilizing Oil has not only made the structure more stable, it’s held off the greying effect of weathering significantly.”

Untreated timber

Some architects have been using untreated timber externally, such as oak windows or cedar claddings. And, while treatment suppliers recognise that some timbers, including many hardwoods, are more naturally durable than other species, they 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 David 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, giving more predictable performance.”

Looking further ahead, David Law expects tightening regulations will require more robust testing. “New field test requirements will mean minimum five-years’ field test data must be available,” he said. “This will stabilise the market as it will be harder to introduce new products. Niche products are appearing and have their place – but they tend to be expensive or you require high initial capital outlay that restricts their market.”