The Juan Manuel Zafra Secondary School is located at 51 Rogent Street, in the Dreta de l’Eixample district of Barcelona. The first and main building was built at the beginning of the last century with a clear post-industrial Modernist aesthetic. At the end of the 1980s, the vocational training school was considered its expansion as a result of the insufficiency of teaching spaces and the difficulty of adapting the school to the new school programs. In this situation, it is proposed to build a new building that would house the entire theoretical teaching program, leaving the practical classrooms, workshops and administration of the centre in the old building. The new building will also house the sports support program at the school, consisting of a multi-purpose gymnasium and changing rooms. The school's floor availability was very limited and was reduced to the playground. This is located in the void left by the buildings at number 598 of Provença Street. This space of very tight dimensions was also flanked by the large partitions of the adjoining residential buildings. One of the most important decisions was to maintain the character of the inner courtyard of the block open to Provença Street and thus visually free the old school. Therefore, the new classroom could only be located on one of the short sides of the courtyard and sandwiched between two partitions of the two neighbouring buildings. The regulatory length of the playing court immovably fixed the position of the façade. This fact meant an exercise in continence and compaction of the program in height. With this situation, the idea of considering the volume defined by the twelve classrooms as a box suspended in space and presiding over the playground as the main piece arose. The rest of the program, services, tutorials, stairs and others are literally attached to the existing partitions, solving the lack of orthogonality of them. The circulations that occur between the service strip and the classrooms emphasise this autonomy of the main volume even more. The rest of the program is located below the level of access from Provença Street. The gym, as a large empty space, is located on the double-height basement floor with a direct view from the access porch. Keeping the level of the sports court at the same level as the ground floor of the old school allows for the optimisation of the school's internal circulation and a lower fence on a more humane scale. We believe that the programmatic rigour and rationality at the same time as considering its construction have favoured the final clarity of the intervention.