Mechano-Sorptive Nailplate Backout in Nailplated Timber Trusses
Plated timber trusses are used in most Australian homes. They’re a reliable and cost-effective solution. However, problems with trusses were reported in 2002. In the decades since construction the nailplates used to join the truss timbers had backed out, weakening the joints. Subsequent inspections of other buildings found similar examples of nailplates backing out of joints and reducing the strength of the trusses.
The major recommendation was that all roofs be sarked to prevent external moisture penetration. Other changes to the manufacture of timber trusses were also suggested. The study’s findings are being assessed and implemented by industry.