LAUSR

Abstract Wood is frequently used for claddings and decking where it is exposed to moisture and various biotic agents limiting its serviceability. In-situ moisture monitoring can help to determine the moisture-induced risk for decay and might therefore serve as faster alternative to traditional durability testing, which usually requires exposure for many years. This study aimed on determining the moisture-induced risk for decay of differently severe exposed wooden components, i.e. combined facade-decking elements and horizontal double layer set ups mimicking poorly designed terrace decks made from twelve different wood species and thermally modified wood. The huge variation of moisture-induced risk for decay of timber used above ground became evident. Dosage as well as service life estimates differed in dependence of wood species, design detailing, and decay type to be expected. An exposure dose was utilized for alternative durability classification of timber in less severe exposure conditions such as for cladding applications and compared with common durability classification based on decay assessment. Differences in durability between the various wood species and materials became apparent in the horizontal double layer and met fairly well the expectations based on durability classification according to the European standard EN 350 and previous findings from above ground field tests. Combined facade-decking elements were found to be useful for moisture content (MC) monitoring of wood in less severe exposure situations such as facades and freely ventilated decking, but not for correlation between moisture induced risk and fungal decay, since the latter occurred exclusively at water trapping contact faces. Nevertheless, the use of MC and temperature recordings combined with a dosimeter-based decay model might allow for an alternative time-saving way to estimate and classify wood durability.