Innovative mortar applications for the retrofitting of modern heritage buildings

The conservation and adaptive reuse of heritage buildings present critical challenges in balancing historical preservation with modern energy and structural requirements. This research presents a comparative study of five pilot interventions from the EU-funded SINCERE project, each employing innovative mortar technologies tailored to the climatic, structural, and regulatory contexts of heritage structures in Israel, Spain, Czech Republic, Greece, and Malta. The case studies include mock-ups at Demo Park in Madrid as a testbed, a brutalist-style university building in Holon, an industrial steel-framed building in Ostrava, a neoclassical Ottoman school in Rhodes, and an early 20th century coastal searchlight post in Malta. Across the sites, mortars incorporating hempcrete, textile reinforcement, and phase-change materials among other constituents are evaluated for their performance in thermal retrofitting, environmental resilience, and heritage compatibility. For the data on thermal performance, the network of sensors is applied. The Madrid pilot offers a controlled experimental setup through four full-scale mock-ups, allowing side-by-side performance comparison of different mortar formulations under real climatic conditions. In the Rhodes and Ostrava pilot pro, materials are integrated within conservation frameworks sensitive to national heritage regulations. Holon site tests the feasibility of retrofitting inhabited structures without altering their heritage value or disrupting daily use. The Malta pilot, situated in an aggressive marine environment, offers valuable insight into the performance of repair mortars on concrete surfaces, exposed to salt crystallization, and thermal renders on limestone masonry. This research highlights how advanced mortars can enhance energy efficiency and material resilience while maintaining architectural authenticity. The results are intended to underscore the importance of specific material design, passive energy strategies, and scalable monitoring tools in achieving sustainable heritage retrofitting, contributing to a toolkit for conservation.