The Priory's 11th century monks' toilet block (reredorter) may well be the first example of a layout that came to be used in most monasteries. The toilets were built over a sewer. Chutes led down from each toilet to the sewer, which channelled away the waste. It is possible to see the sewer under the far wall in front of you.
There were 10 cubicles here but no doors seem to have been provided so the monks did not have much privacy. The three large windows (to your left) provided light and ventilation. A later raising of the the ground level has now blocked them off completely. There was probably a bath house at the west end of the building.
By the end of the 12th century a new, larger toilet block was built to accommodate the growing number of monks. A longer dormitory was then built over the older toilet block.