Ongoing Failure of Treated Timber posts in ground contact – Statement from the Association of Fencing Industries

Ongoing Failure of Treated Timber posts in ground contact – Statement from the Association of Fencing Industries

Based on the responses to our timber treatment survey, there is no doubt that there is a serious problem with reliability concerning current chemical treatments – there have been considerable numbers of failures. Contractors are often having to accept most of the resulting costs and suffering a loss of reputation with clients. The AFI cannot allow this situation to continue unchallenged.

Whist the Wood Protection Association (WPA) has acknowledged that there have been examples of premature failure of preservative treated wood in ground contact over recent years. They feel that the overall prevalence of such failures is being overstated and the reasons behind them misunderstood. The WPA view is that the keys to ensuring consistent quality and performance are:

  • Promote the correct specification of treated wood to be used in ground contact (with an understanding of what that means).
  • Promote the use of timber treatment companies with independent third-party accreditation, primarily through their Benchmark quality scheme.
  • Explain that contractors and users will get what they pay for – cheap product will probably not perform, so buy the best and be prepared to pay a premium which will give better long-term value. The AFI’s view is that there is a substantial problem with timber treatment products for many years and despite the WPA’s feeling that the problem is overstated, it is time for them to stop burying their heads in the sand. We have numerous examples of significant failures of product produced to UC4 standards by established treatment companies (many of them WPA members) failing prematurely. Too many for these to be isolated incidents.

It would seem to us that, despite the care taken by treatment companies to follow the processes given in BS8417 regarding timber treatment, failures are still occurring and consequently either the process or the biocides used in the process are failing. There are a number of companies promising 12-15 year life for their products but in the main these will only cover supply of replacement materials and then with numerous caveats and conditions. Our view has always been that, if the treatment industry believes in its end-product then it needs to put its ‘money where its mouth is’ and provide proper guarantees covering the full cost of replacement.

As it seems that the treatment industry is not prepared to do this the Association of Fencing Industries has no choice but to recommend to all installers that they only use chemically treated timber in ground contact where this is a specific requirement by the client and that the client is made aware that failure of the posts due to fungal attack is not the responsibility of the installer. Clients should also be made aware that, where the timber is guaranteed by the supplier, there are often considerable conditions to those guarantees which means they are unlikely to cover the cost of a replacement fence.

As an association we have been reluctant to do this up to this point in the hope that the WPA and its members could either find a solution to the problem or introduce a proper guarantee scheme to cover full costs of replacement. Timber in ground contact has been a staple of the fencing industry for as long as there has been a fencing industry and we are reluctant to change that but technology has moved on with alternative materials and designs which can offer a long life expectation (well in excess of 15 years) which timber is failing to do in many cases.

The evidence we have from our questionnaire leaves us in no doubt as to the necessity of this step to protect the interests of our members and to alert the fence-buying public to the potential risks of using chemically treated timber in ground contact.

The full results of the survey are available here. For further information contact us at