IN-PERSON Manchester Livable Cities

Abstract

Urbanization, climate change, and the global shift toward sustainable development have intensified interest in green infrastructure, particularly ex-tensive green roofs. This study critically investigates the environmental performance of extensive green roofs in a humid temperate climate, with the specific objectives of comparing the thermal and energy performance as well as carbon footprint of green roofs to conventional steel roofs. The comparison assesses the influence of different insulation materials to identify the best performing applications. Building simulations were performed using IESV software to evaluate indoor thermal comfort, carbon-emission reduction, and overall energy performance. The Leicester College for Aeronautics and Space Engineering was used as a case study and two model categories were created: Model X, featuring a traditional steel roof, and Model Y, incorporating a green roof system combined with one of five insulation mate-rials: glass wool, foamed glass, rockwool, expanded polystyrene, or polyure-thane. The IESVE simulations revealed that Model Y with polyurethane insulation demonstrated an average indoor air-temperature reduction of ap-proximately 1 °C during summer compared to Model X. Green-roof configurations also produced lower U-values compared with the steel-roof baseline, with polyurethane yielding a reduction of 0.08 W/m²·K. Additionally, the polyurethane-insulated green roof achieved a 33% decrease in carbon emissions relative to Model X. Among the tested insulation materials, polyurethane consistently delivered the most favorable performance outcomes. The findings provide useful insights for building professionals across the construction industry when selecting insulation materials for green-roof systems.