This research investigates the structural-typological characteristics of reinforced concrete (RC) school buildings constructed between 1950 and 1980 in Italy aimed at supporting large-scale seismic vulnerability assessment. Drawing from detailed surveys of 30 schools and archival research, the work identifies four representative expert-judgment based structural archetypes, capturing recurrent features mainly based on typical in-plan characteristics of the buildings and accounting for other parameters such as number of storeys, plan geometry, frame system regularity, and infill layout. The analysis reveals common vulnerabilities, including soft-storey mechanisms, torsional irregularities, short columns, and inadequate reinforcement detailing, all of which critically affect seismic performance. Despite some favourable traits, such as rigid diaphragms and low-rise mass, the structural response is often dominated by irregularities and brittle failure modes. The classification aligns with national seismic risk mitigation frameworks (e.g., School-MARS) and provides the basis for the development of typology-based fragility models. These results may support targeted retrofit prioritization and contribute to a more refined archetype-driven approach to school vulnerability assessment, promoting scalable strategies for seismic resilience.