Durability of historic structures repaired with adhesives

Adhesives for onsite bonding of wood were firstly used for interventions on old timber structures. In general, an ever increasing trend has developed during the last thirty years in using epoxy adhesives for wood consolidation, mainly thanks to the excellent adaptive capability of these products to the various proposed design solutions and operational conditions, together with their good mechanical performances. While the intervention practice is well established, some concerns exist about the long-term durability of joints, because of the different behavior between wood and epoxies when they are exposed to hygro-thermal cycles in service life. A series of inspections on real cases of timber structures repaired with epoxies evidenced the appreciable influence of the effective execution of the joints (geometry, wood species, gluing procedures etc.) and allowed to make reliable evaluations on the durability of this kind of interventions.