Impact of roofing materials on school temperatures in tropical Africa

Increasing extreme heat events in schools in the tropics are creating dangerous learning environments for children. There is limited data, however, on the extent of extreme heat in such classrooms and effective heat mitigation strategies. This study presents the first long- term analysis of classroom temperatures in Ghanaian schools, measuring conditions in 16 classrooms in Accra over 389 days. It highlights the conditions experienced by schoolchildren and examines how roof type influences classroom temperatures. Children in metal-roofed classrooms were exposed to extremely high temperatures of up to 39.8°C, exceeding outdoor temperatures by up to 5.9°C, and being overheated for 72.5% of occupied hours, posing risks to children’s health and learning. Concrete-roofed classrooms were significantly cooler than those with metal roofs (by up to 5.8°C) and were on average 1.2°C cooler than the outdoor temperature, thus exposing children to fewer hours of uncomfortably hot temperatures. Adding a plywood ceiling under a metal roof halved indoor temperatures and overheating hours, compared to a bare metal roof. These findings highlight the need for heat-resilient design principles when constructing or retrofitting schools to create safer, healthier classroom environments that are more conducive to supporting learning opportunities and the health of children in tropical climates.