A possible approach for seismic upgrading of existing reinforced concrete framed buildings consists in the creation of an additional structure connected to the existing one from outside. The installation of steel exoskeletons on the building façade is an application of this approach. This seismic upgrading technique provides several advantages: it can be realized without interrupting the building operativity, it allows a high level of prefabrication, it can be combined with energy efficiency solutions, and also used for the architectural restyling of the building. However, the availability of space around the building is a mandatory requirement for its installation.In this framework, the paper investigates the potential application of a 3D exoskeleton technology based on the use of customizable three-dimensional steel trusses. The investigation is carried out with reference to a building selected as case study. It specifically involves a technical analysis of the proposed seismic upgrading intervention that is combined with an energy-efficiency solution based on prefabricated panels to be applied to the building façade. The potentialities of architectural integration of the retrofit intervention are also examined in compliance with a multidisciplinary design approach.