The effects of fungal decay on timber connections: a systematic review

Abstract

Connections are critical for the integrity of timber structures, yet they are highly susceptible to reduced capacity due to moisture intrusion and subsequent fungal decay. While the effects of decay on clear wood are well documented, the impacts on the mechanical performance of connections remain comparatively underexplored, particularly during early decay stages (< 10% wood mass loss), when substantial reductions in wood strength can occur. This literature review consolidated the current state of the art, identified methodological inconsistencies, and defined key knowledge gaps in the study of fungal decay on timber connections. A systematic search of academic databases identified laboratory studies investigating the effects of fungal decay on timber connections. The review revealed substantial variability in experimental methodologies, including wood species, fastener types, sterilisation methods, and decay quantification techniques, which complicates direct comparisons between studies. The review showed a critical need for standardised protocols to isolate the effects of decay from confounding variables like moisture content and sterilisation pre-treatments. Based on these identified gaps, it is recommended to improve future testing approaches and enable more reliable evaluation of decay effects on connection performance. These insights support the development of durability-focused research, design guidance and predictive models for the long-term performance of timber connections.