The core focus of the Wood Protection Association’s (WPA) annual conference was the essential role of industrial pre-treatment in helping to make the most of wood as a sustainable, low environmental impact material.

WPA chairman Chris Coggins opened by telling the 70-strong audience at the April event that pre-treated wood was a “complementary fit with modern materials thinking”.

“By conferring durability on non-durable species and fire protection properties to solid timber and panel products, wood protection technologies enable wood’s embodied carbon to be stored for longer,” he said. “That makes them compatible with sustainability and circular economy objectives for materials of modern construction.”

WPA director Steve Young agreed, adding that the conference objective was also to address “challenges to growing demand for treated wood”, so the sector could capitalise on timber’s overall increasing opportunities. Dr Coggins himself looked at factors driving changes to the BS8417 Wood Preservation standard. These included concerns about the variability in durability of plantation-grown species heartwood compared with natural forest material, new performance data and impact of international standards such as CEN and ISO. And more change is in the pipeline, he said, with EN 350’s stipulations on durability of natural, modified and treated wood under revision.

As regards specification for the 15-year desired service life of materials in Use Class 4 (UC4), BSI has agreed to await data from the WPA and BRE UK softwoods field trial at sites in Scotland and England.

Derek Tweddle, managing director of Tweddle Engineering Ltd, told delegates how latest developments in incising technology, like its Excalibur machine, were further enhancing treatment, and subsequent performance, of resistant species like spruce and species with more dense heartwood such as Douglas fir.

There remains a strong body of opinion internationally that creosote should also remain part of the timber treatment armoury to help extend wood’s service life in the widest range of applications. And Willie Clason, chairman of the WPA Creosote Group, described latest developments from the European creosote sector campaign, which, while also evaluating alternatives in the event of a ban, is pushing continued approval of its use He said that, following development of a ‘robust Socio Economic Assessment’ by the campaign, Kemi, the EU creosote competent authority in Sweden had approved continued use of creosote for poles and sleepers to 2021. The campaigners were subsequently seeking mutual recognition by other EU national authorities, including the HSE in the UK, which was considering creosote use for sleepers, poles and fencing/tree stakes.

Turning to fire protection, Gordon Ewbank said the inability of UK government to enforce Construction Products Regulation compliance on the issue was the biggest challenge facing the UK fire retardant wood treatments sector.

Consequently, Mr Ewbank, WPA Fire Committee chair and regulatory advisor, said the industry’s reputation and public safety standards were threatened by emergence of site applied coatings and non CPR-compliant timber sheet materials used structurally. The WPA is consequently starting a lobby campaign on the issues.

Mr Ewbank also tackled whether the UK is at a competitive disadvantage due to uneven implementation of the EU Industrial Emissions Directive (IED). He said the WPA was inputting into the ‘permitting process’ on the issue and keeping abreast of development of the IED’s BREF best techniques document. Looking forward, Mr Young said the WPA’s mission must be to bring all these strands together to ensure the treatment sector maximises its opportunities in an era of growing ambition in wood use, and helps enhance timber’s performance potential in an ever wider range of higher spec applications. “Treated wood performance remains a concern in some sectors, which needs addressing,” he said.

“Key will be our ability to educate specifiers on benefits of wood protection and to leverage growing popularity of timber in construction.

We’ve put in place the tools in the form of the WPA Benchmark quality assurance and preservative product approval scheme and ensuring their wider adoption is a key objective, as is driving overall membership and funding growth.”