The earthquake of L’Aquila on the 6th April 2009 was the fifth stronger earthquake recorded in Italy. To support citizens, around 3300 timber house modules have been built in the region of L’Aquila. These single- or two-story buildings are characterized by total surface from 40 to 70 square meters, realized by employing two of most common wood-based earthquake-resistant structural systems, namely the light-frame or the cross-laminated timber (CLT) system respectively. After 13 years, these structures require maintenance interventions to preserve their original functionality, as also emphasized by recent accidental partial collapses and by individual diagnostic investigations. Among others, this paper reports some major experimental evidences which have been collected from in-field monitoring investigations on timber load-bearing components. Most importantly, the attention is focused on the proposal assessment of a rapid but reliable operational protocol and monitoring strategy which could be applied for diagnostic purposes, based on vibration frequency analysis and its modification over time, to possibly monitor “rapidly” and timely retrofit such a wide number of timber modular houses.
