Members of the Timber Trade Federation (TTF) are on a mission to grow the demand for preservative-treated wood. At the heart of this mission is a major quality initiative to reassure buyers that the performance of treated wood products can be trusted.

To ensure the trust-building could be achieved consistently TTF members voted to make the third-party quality assurance of treated wood mandatory TTF policy. The deadline for compliance with this policy is the end of June. After this date treated wood placed on the UK market by a TTF member must be produced by, or purchased from, a treatment operator who has been assessed and approved under an independent and reputable quality assurance scheme such as the WPA Benchmark operated by the Wood Protection Association (WPA). The policy applies equally to treated wood products sourced in the UK or imported.

Nowhere is the need to build end user confidence in the efficacy of treated wood more acute than in the fencing and landscaping sector where products are used in direct contact with the ground or very close to the ground. These are what are known as the Use Class 4 (UC4) applications in British Standards. They are the end uses where wood is permanently exposed to the weather and frequently wet for extended periods of time. Challenging service conditions where it is essential that the durability of a treated wood product must give a predictable service life – 15 years being the default service life for UC4 applications specified in BS8417, the British Standard for preservative-treated wood. This standard also specifies the level of preservative treatment necessary to protect wood in the other main application Use Classes – UC1 and UC2 for indoor applications and UC3 exterior out of ground applications such as fence rails, decking boards and timber cladding where the potential for fungal decay is much lower.


It is treated wood in UC4 ground contact applications that are most often the subject of negative PR relating to reports of poor performance in service. If a treated wood fence post fails after a few years, it is almost always the efficacy of the wood preservative that is called into question. “There are many reasons why a treated product may decay prematurely but a lack of efficacy is not one of them.” says WPA Director Gordon Ewbank who confirms that a major field trial of UK softwood fence posts is starting to provide clear evidence that wood can be relied on when correctly treated for its end use. “Ensuring fitness for a purpose is the responsibility of both buyers and suppliers,” says Gordon who explains that buyers have a responsibility to correctly specify the products they want and wood treaters have a responsibility to have the quality control procedures in place that enable them to deliver those products consistently. “That’s why the strictest third-party criteria are applied to the accreditation of all UC4 treated wood products under the WPA Benchmark quality scheme,” adds Gordon.

This is a view shared by the TTFwhich has reaffirmed that there can be no compromise on the quality assurance aspects of the Treated Wood Action Plan agreed by its members. In consultation with the WPA, it has recently redefined the pathway to compliance under the WPA Benchmark quality scheme which has two distinct but interrelated Accreditation Classes – one for wood treaters and one for treated wood products.

The WPA Benchmark is a third-party quality assurance scheme launched in 2011 as a credible way for UK wood treaters to address the quality assurance needs of their customers. It is one of several quality schemes for treated wood that operates in Europe and Scandinavia.


Following the decision of TTF members to make third-party quality assurance for treated wood mandatory, the WPA has received a record number of new applications to join the WPA Benchmark QA Scheme with treaters seeking approval for a wide range of treated wood products in all application Use Classes.

WPA and TTF believe that the requirement for laboratory analysis is best focused on the most critical ground contact applications and have agreed that TTF members may initially operate as ApprovedTreaters with laboratory testing reserved exclusively for the quality accreditation of Approved Products for UC4 applications. Approved Product accreditation can only be granted to a company already holding Approved Treater status.

The WPA Benchmark QA Scheme is available to any wood treater or business producing treated wood for the UK market.

To find out more about the WPABenchmark QA Scheme for preservative-treated wood and the routes to compliance see

For further information contact Steve Young: 07774 449206 

Fencing News Blog