King's School Canterbury – Mitchinson's Day House

The tight site within the Conservation area of Canterbury, chosen to provide a day house for 70 non-boarding pupils, contains the remains of a medieval hospice (a Scheduled Ancient Monument) which forms one external façade wall. The Grade II-listed day house comprises study and social spaces, changing rooms and a kitchenette.

The goal for the project was to provide a high level of occupant comfort, while maximising the use of passive design principles to minimise operational energy consumption. The site has many constraints; the historical context and archeological significance mean that many conventional renewable technologies were deemed unacceptable, while other planning conditions meant that glazing, particularly on the first floor, would have to be limited.

The building’s form reacts to these constraints by providing an abundance of daylight and fresh air through both a glazed courtyard and a number of rooflights. A thermal energy model was developed at an early stage to inform the architectural detail, thermal performance and environmental design of operational systems. High daylight levels combined with efficient LED lighting and daylight dimming controls significantly reduce the building’s artificial lighting energy consumption. The thermal model also informed the design of a number of discreet rooflight actuators, which are controlled automatically via temperature and CO2 sensors in each study space. An overheating assessment also proved that passive night cooling could be utilised through the rooflight openings to ensure the building remains comfortable throughout the summer months.

The project achieved BREEAM Very Good. It is one of a series of commissions carried out by Skelly & Couch for the King’s School Canterbury. Others included in the school’s £48m plan are the Malthouse performing arts centre; Kingsdown House boarding accommodation; a new £10m science building in the Mint Yard (Precincts); and a new residential building designed for 80 international students.

Shortlisted for an AJ Retrofit Award 2019 (School category).