The existing masonry and reinforced concrete built heritage is generally aged and inadequate to the seismic and energetic requirements due to natural hazards and climate change, characterizing present times. Innovative techniques deserve strong interest for improving the building perfomances, especially if including multi-task approaches. Eco-friendly and eco-sustainable materials and systems are preferred. Therefore, timber-based elements represent an optimal option, thanks to the intrinsic physical and mechanical properties of wood, among them lightness, high strength-to-weight ratios and natural sustainability, as well as easiness of production and realization along with favorable energetic performances. For these prerogatives, in recent years, timber has become a trend worldwide in the construction sector. New techniques based on the use of timber are gaining popularity for restoring existing structures belonging to historical, artistic and also productive built heritage.
In this framework, the paper presents an overview on the main researches and applications concerning timber-based elements for the retrofit of existing buildings. Two macro-categories of interventions, such as global and local ones, are defined: the first includes additional timber exo- and endo-skeletons, while the second concerns the strengthening of single structural elements. The peculiarities of the interventions in the context of seismic and energetic integrated design are emphasized.