The upper storey would have housed the brothers' dormitory, or dorter, and was connected to their facilities for ablutions, or reredorter (as the latrines are upstream from the kitchen, which is to the south here, they would have been on a separate water course). The ground floor might comprise day rooms, working rooms or undercroft cellars for storage and the like. At Furness the ground floor constituted the largest monastic undercroft in England.
Wikipedia article:
http://en.wikipedia.org/wiki/Furness_AbbeyCategory:
living quarters