Nestled between the pentice and the refectory, was an ancillary building, measuring 4.50m by 7m. This small building had three walls built in stone whilst its northern frontage appears to have been of timber construction. The structure lay at the northern limit of the western range. It may have formed part of the prior's private suite of buildings, serving either as a separate meeting hall, or a ground floor store below an accommodation wing. The building had two points of entry: a doorway to the south gave direct access to the prior's lodge, whilst a doorway to the northern courtyard and was presumably used as a service entrance.

The construction of the ancillary building appears to have been constructed during the late 12th century when the rest of the western range was being built. Apart from being re-floored once and a remodelling of the northern threshold the building remained unchanged until its demolition in c. 1538

Hicks, M., 1989, 'St. Gregory's Priory: The Church and Conventual Buildings' (Article in serial). SKE30366.

Hicks, A. & Hicks, M., 2001, St. Gregory's Priory, Northgate, Canterbury, Excavations 1988-1991 (Monograph). SKE30367.