Cost evaluation of seismic and energy retrofit for apartment blocks in southern Italy

In Italy, over 75% of the building stock is not only highly energy-consuming, but also earthquake-prone. Hence, energy renovation actions should be combined with seismic retrofitting. However, a number of barriers (economic, organizational, technical, cultural, legislative, etc.) considerably limit the real possibility to extensively undertake combined retrofit actions, especially for multi-owner and high-rise housing. Since the economic barrier often represents the main leverage to undertake renovation actions, this paper aims at determining the average price and the payback time (PBT) of seismic and energy retrofitting of apartment blocks. To this purpose, we have selected as case study a group of six edifices located in Catania and representative of the residential stock built in southern Italy in the period of greatest urban expansion (1950-1980). The average cost has been defined considering different retrofit interventions, according to the specific features and requirements of each building. Results have shown an average unit cost as high as 440 €/m2 and – thanks to the current fiscal incentives and the reduced energy bill – a PBT of about 11 years that represents a promising value, also to get bank loans.