Performance of untreated timbers in above ground decking tests: Preliminary results from an international collaborative trial ; Paper prepared for the 50th IRG Annual Meeting, IRG/WP 19-10940, Quebec City, Quebec, Canada. 12 - 16 May 2019

The ability to accurately predict wood decay risks under varying environmental conditions has long been of interest to timber users. Accurate predictions are difficult owing to the myriad of variables associated with the decay process including wood species, wood inhabiting organisms, timber building element design and environmental conditions. Despite these difficulties, decay predictions have been extensively studied, especially in Europe. Predicting decay in non-soil contact exposures represents a less complex process and reasonable predictors of decay risk have been developed using number of days with measurable rainfall and temperature. One drawback of many decay trials is the limited number of environmental conditions examined. The international decking test discussed in this paper was established to create data under a wider range of environmental conditions. Spotted gum along with slash pine heartwood and sapwood were exposed at seven sites in Europe, South-east Asia, Australia and North America. Participants also exposed local species at their test site as well as at the main Australian site. Preliminary results are discussed in relation to site severity as well as the known durability of the various species. The trial is continuing.