To achieve the ambitious target of climate neutrality of the EU set out within the EU Green Deal, a reduction of energy use in the highly energy consuming building sector is critical. To achieve this, the renovation of existing buildings has been given a key role, starting with the Renovation Wave initiative. In fact, a large proportion of existing buildings in the EU are characterised by a high energy consumption for heating and cooling, often caused by poor or non-existent thermal insulation, as well as outdated heating and cooling systems. It is hence critical to improve their energy-efficiency through renovation to reduce the significant impact of the built environment on the total EU energy household and associated greenhouse gas emissions. Additionally, in Europe's seismic regions, earthquakes can cause significant human and economic losses, with a large impact on society. Recent seismic events have highlighted the vulnerability of older buildings with structural deficiencies that are in dire need for seismic retrofitting. It appears that a large proportion of the EU building stock requires renovation from both structural and energy perspectives. While these are typically addressed separately, recent scientific developments highlight better cost-effectiveness, safety and efficiency can be achieved when taking an integrated approach to building renovation. This report presents materials and technologies being developed and presented in the scientific literature, ranging from integrated exoskeleton solutions, over strengthening and insulation solutions for the existing building envelope or their replacement with better materials, to integrated interventions on horizontal elements like roof and floor slabs. While the field of integrated structural and energy retrofitting is still in its infancy, valuable results and insights have already been obtained. Proposed technologies are presented and critically analysed in terms of their relative effectiveness, invasiveness, impact on the building use disruption, costs, as well as their impact on the environment. Further experimental research and validation of fully integrated retrofitting systems, which can be applied simultaneously at a low cost, is still needed. Together with pilot applications on existing buildings, this will demonstrate the full potential of integrated renovation approaches. The renovation of our ageing building stock will be a key element of the path towards a carbon-neutral EU and combined retrofitting techniques provide a cost-effective solution in seismic region, with a potential for accelerating renovation rates.
