User-Oriented Methodologies and Techniques for Deep Energy Renovation in Social Housing. The Add-Ons' Strategy Based on Multiple Variables

The main energy challenge concerns the efficient renovation of the existing buildings stock, which counts for two third of the overall energy consumptions in the EU; yet, so far, only 1,2% of existing buildings gets renovated every year. The actual investment gap in the deep renovation sector is due to the fact that consistent investments are required up-front and they are generally characterized by an excessively high degree of risk and long payback times. In the search of strategies to overcome these barriers, the work here presented investigates the benefits of non-energy-related factors in the renovation of existing buildings. Indeed, the research hypothesis is based on the assumption that an empowering synergy can be created between old and new buildings, not only in structural, functional but also in economical and social terms. In particular, the aims is to validate a design methodology based upon the creation of additional volume on existing buildings (Add-Ons) intended as roof-top or aside extensions, enclosures, parasites additions or façade transformations. The Add-Ons thus become the main instrument of a multi-disciplinary renovation strategy that increases the viability of energy renovation and ultimately fosters the building market. The technical and economical feasibility has been tested in three different European urban contexts (Italy, Germany, Greece), by applying the principles of industrialisation and mass customization. The result is a prefabricated, modular and adaptive construction system that directly expresses the internal programmatic need for transformation of the buildings and reduces the overall energy consumption. The highly replicable nature of the presented methodology, the important impact on the market and the possibility of overcoming the existing social barriers demonstrate the innovation character of the proposal indicating the path towards an effective turn-around in the energy renovation of buildings and cities, a step forward in defining a new paradigm of sustainability.