Rooftop extension as a solution to reach nZEB in building renovation. Application through typology classification at a neighborhood level

In order to achieve the emission reduction target for 2030, European Commission requires member countries that from the end of the decade onwards, only nearly zero-energy buildings (NZEB) are built. The renovation of the building stock is essential to achieve this goal. Working in consolidated urban contexts is very complex, so in this paper a solution to facilitate the process is proposed. This paper has developed a methodology for designing a roof extension and renovating an existing residential building as a measure of housing creation in already consolidated neighborhoods, and achieve a nZEB and ZEB renovated buildings. Based on typological classification of residential buildings, a single solution applicable to a multiple number of cases is provided to maximize the potential of the proposed solution. This solution was implemented in Chantrea neighborhood in Pamplona, Spain. The results show that it is possible to carry out the renovation of a residential building with a rooftop extension that complies with requirements for models nZEB and ZEB, and to apply this solution on 27 % of the neighborhood stock residential buildings. This would provide a reduction of total primary energy consumption of 62 % (nZEB) and 74 % (ZEB).