St. Denys is a Senior Boys Boarding House which accommodates boys from Year 10 to Upper Sixth. The ethos within the house is founded on trust, collective responsibility and mutual respect as the house is seen as a home away from home for every boy. The concept of family is also central to the dynamics within the house. St. Denys is located in a quiet corner of the campus and benefits from its own private outdoor recreational area where the boys have the opportunity to socialise with friends or play some version of a ball game. Facilities within the house include a computer room, common room and a well-resourced social area with its own cooking area.

Provision for pastoral care within the house is managed by an experienced and caring team of tutors. These tutors are the first point of contact for each boy in ensuring that their emotional, social and spiritual needs are being met; additionally, tutors support the boys in ensuring that they meet their academic commitments through a robust and carefully structured house system.

A vital and central figure in the house is that of the Matron, Miss Wood, who is responsible for the daily administration and management of the house and associated logistical matters.

Boys are given leadership opportunities within the house through a structure of prefects and family units and various duties and responsibilities are assigned.Together, boys and staff help to ensure that St. Denys is a caring, considerate and successful family community.