Thermal Performance Assessment of an Extensive Green Roof in a Building Retrofit Using Infrared Thermography

The importance of sustainability in building construction has positioned green roofs as essential tools for sustainable construction in large urban centers. The present study investigates the implementation of an extensive green roof and its impact on building external surface temperature. In this sense, a comparative analysis was performed considering three types of roofing systems: (1) fiber cement tiles, (2) conventional concrete slab, and (3) extensive green roof. Temperature data were collected using infrared thermography to evaluate the thermal performance of each system. The results revealed that the green roof significantly improved the external surface temperature, with an average temperature reduction of approximately 17.31 °C compared to the fiber cement roof and 13.46 °C for the concrete slab. The combination of high solar radiation absorption and low heat dissipation capacity resulted in elevated surface temperatures on fiber cement and concrete surfaces. On the other hand, the green roof significantly reduces surface temperatures due to the combined effect of a slightly higher reflection coefficient, moderate emissivity, and evaporative cooling. These results emphasize the role of green roofs in mitigating the urban heat island effect and promoting environmental sustainability, aligning with the principles of energy efficiency and green engineering. Finally, a renovation of the building was also carried out, including structural reinforcement to accommodate the additional 0.972 tf/m2 permanent load imposed by the six-layer green roof system and variable loads. Thus, this research may represent an advance in comparing the thermal behavior of green roofs against fiber cement and concrete roofing systems.