St Paul’s Cathedral School is a co-educational preparatory school for boys and girls aged 4 to 13 and a residential choir school for the boy choristers of St Paul’s Cathedral.
The school identified a need to increase capacity and improve its facilities to its pupils. The project included building a new boarding house, which was to provide accommodation to reflect current regulations, with the desire to exceed the expectations and to secure the culturally significant English Choral tradition for future generations. The accommodation, running over two floors, includes 36 beds, common rooms currently configured as a games room and cinema room, bathrooms, plus ample quiet social spaces. The building also included residential staff accommodation, more classrooms, ICT suite, an enlarged and refitted dining hall and kitchen and bespoke play equipment.
CBG Consultants was appointed to provide M&E design and sustainable consultancy services for the project. The CLT extension provided a good opportunity to reduce energy costs through high insulation and low infiltration rates inherent with the timber panel building system. The building was modelled to test overheating and the detailed design incorporated feedback from the modelling including optimising glazing selection and variable ventilation rates within the spaces to mitigate both occupancy numbers and summer overheating.
The boarding house design faced the problem of requiring adequate fresh air, avoiding overheating, and keeping out road noise and pollutants whilst being connected to a Grade 1 listed building. Large air conditioning plant was ruled out in favour of opening windows supported by discreet ventilation units, co-ordinated into the building design.
The design team recognised the location significance and the planning conditions concerning internal air quality. Mechanical Ventilation and Heat Recovery Units (MVHR) were provided locally for each boarding room and communal spaces, running at continuous low speed operation with boost triggered by air quality sensing. Final filtration included NO2, PM2.5 and PM10 modules.