Current conditions of building heritage claim urgent solutions to solve its multiple deficiencies. Recent earthquakes and extreme climate events have shown that postponing interventions to face such issues is no longer acceptable. Current retrofitting strategies seem unable to efficiently address this challenge and the deficits of existing buildings, which regard both energy and structural aspects. Indeed, in the last few years, ordinary interventions have focused on solving episodic deficiencies or single issues, missing the opportunity for an integrated and holistic refurbishment. Within this context, the study and development of new materials and strategies are of primary importance, also aiming at sustainable practices. Thus, nature-based solutions (NBS) emerged as a valuable answer to the climate crisis and global warming consequences. In this study, an innovative composite reinforced mortar (CRM) system with enhanced thermal properties was developed and experimentally tested for integrated retrofitting applications. Taking inspiration from nature, a lime-based matrix incorporating coffee biochar was used within the CRM system to decrease the thermal conductivity using a bio-based product with considerable environmental advantages. However, such benefits are associated with some disadvantages, such as a worse mechanical response, usually inadequate for seismic strengthening interventions. This work aims to investigate the tensile and pull-out behaviour of a CRM glass fibre mesh embedded in a special mortar specifically developed, thus showing its suitability and potential for this kind of application. The output from this study opens interesting research pathways and leads toward further improvements in this direction.