Background Promoting sustainable construction is one of the priority actions for achieving EU objectives around resource efficiency, climate change, economic recovery and sustainable development. However, equally important is the fact that 70% of Europeans lives in residential buildings that are more than 20 years old, which were generally built to lower environmental and health standards. These older buildings typically require ongoing renovation over time. These renovations provide a challenge, but also an opportunity to improve the performance of the building in terms of energy efficiency and sustainability. Given that most households have limited economic resources, finding cost-effective ways to achieve this is vitally important. Upgrading of the housing stock requires all relevant actors, including administrations, designers and social workers, to understand the issues at stake and what they need to do. Objectives The NEWsolutions4OLDhousing project aims to establish a standard methodology for the sustainable retrofitting of social housing. This will serve as a tool to help stakeholders overcome some of the existing barriers to the achievement of sustainable housing in the EU. The project will identify new technologies, products and innovative building systems for the retrofitting of social housing and demonstrate the feasibility of their application when tailored to the physical, economic and social conditions of each building or type of housing. It will look at how existing building materials can be used in the construction of more sustainable housing. Based on these experiences, the project will develop an on-line tool to quantify, clarify and classify the sustainability of actions for retrofitting housing. This will provide architects, builders, decision-makers and authorities with greater awareness and knowledge of the sustainable solutions for retrofitting old housing and reusing old materials. The project ultimately hopes to promote the implementation of optimised building concepts that have the potential to decrease impacts associated with the lifecycle of buildings. It specifically aims to: Increase the lifespan of buildings; Reduce the generation of construction and demolition waste by 170 tonnes per retrofitted house; Increase the reuse of building materials and reduce demand for new raw materials by 180 tonnes per house, thereby reducing associated energy consumption by 18.48 Tpe (total power exchange) and CO2 emissions by 68.37 tonnes; Reduce the annual energy consumption in retrofitted houses by 0.33 Tpe (total power exchange) and associated CO2 emissions by 1.22 tonnes; and Increase the comfort and value of social housing, and reduce energy bills for occupiers by some 30% - thus increasing their overall economic well-being by 1.6-4.8%. Expected results: A standard methodology for the sustainable retrofitting of social housing, including an on-line assessment, evaluation and decision-making tool for stakeholders; Decreased energy consumption and resource use in the construction sector; and Social and economic benefits for the social housing sector.