Summer overheating is a growing challenge for cities. In dense urban areas, heatwaves and the urban heat island effect increase discomfort in buildings, especially in top-floor dwellings, while stronger reliance on air conditioning raises energy use and emissions. Cities therefore need passive, durable and replicable retrofit solutions for existing housing stock.
Within the LIFE SUPERHERO project, this challenge was addressed in Reggio Emilia, in Northern Italy. Two multi-storey social-housing buildings were selected as pilot sites to test a roof-based adaptation measure under real operating conditions. The intervention targeted a common and vulnerable building type: ageing residential blocks with poor summer performance and low energy efficiency.
Innovative response to summer heat in the Reggio Emilia pilots
The retrofit involved the installation of a pitched ventilated roof over the existing flat roofs. Its key feature was the use of innovative clay tiles (HEROTILES; see Figure 1) designed to improve air permeability at tile level, enhancing natural ventilation within the roof package. This HEROTILE-based roof solution (HBR) was combined with a step-by-step renovation pathway (also including building-envelope thermal upgrades; see Figure 2) and a structured monitoring plan, making the pilots useful not only as construction works but also as a source of practical evidence.
Figure 1: the two LIFE SUPERHERO pilot buildings in Reggio Emilia before and after roof retrofit, with the HEROTILE Portuguese and HEROTILE Marseille solutions adopted in the two demonstrators.
Figure 2: renovation pathway of the LIFE SUPERHERO pilot buildings in Reggio Emilia, from the original unventilated flat-roof condition to envelope renovation (external thermal insulation, windows, heating system) and final HBR installation.
Monitoring covered different renovation phases, from the original unventilated roofs to the final HEROTILE-based configuration. The project tracked indoor environmental quality, cooling energy use, local weather conditions and roof thermal performance (through a monitoring system, including roof-mounted instrumentation). To support transparency and replication, monitored results were organised in HU-BES, the project’s online data-sharing platform, which makes key evidence accessible to both professional and non-professional users.
Takeaways for cities from the Reggio Emilia experience
The results are highly relevant for municipalities and housing providers. In a selected summer comparison period, the retrofit reduced external roof surface temperature by 18-23% on average and lowered ceiling temperatures by 2-8% compared to the pre-existing flat roof solution. In the same comparison, cooling energy use and related CO2 emissions fell by 44-91%, with an average reduction of about 67%. This shows how passive roof design can contribute to climate adaptation while also delivering mitigation co-benefits.
The Reggio Emilia experience also offers transferable lessons. Early surveys of the existing roof are essential, because older buildings often include added layers and technical constraints that affect design and installation, and best practice document was developed in the project. At the same time, the pilots show that monitored demonstration, clear guidance and open access to results can reduce uncertainty for future adopters. Therefore, for cities looking for scalable responses to summer heat, ventilated and air-permeable tiled roofs clearly emerge as a solution deserving closer attention.
Reggio Emilia is part also part of the Cities Refresh campaign, creating lively and safe places for all. Explore the story now.
Useful links
- LIFE SUPERHERO project website - https://www.lifesuperhero.eu
- Demo buildings page - https://www.lifesuperhero.eu/demo-buildings
- HU-BES platform - https://www.lifesuperhero.eu/hu-bes-data-sharing-platform
- Climate-ADAPT project page (2025) - https://climate-adapt.eea.europa.eu/en/metadata/projects/sustainability-and-performances-for-herotile-based-energy-efficient-roofs-2
The article is a contribution by Nicola Massarini / Centro Ceramico. Centro Ceramico is a research, testing and training centre for ceramic industry, located in Sassuolo, Italy. It is the Coordinator of the Project LIFE SUPERHERO.
Details
- Publication date
- 29 May 2026