Internally, the Upper Church maintains Brother Elias' original simple aisleless cruciform plan. Like the Lower Church, there is a nave of four bays with ribbed cross-vaulting. Unlike that of the Lower Church, it is only the diagonal ribs which are of semi-circular form. The transverse ribs are pointed in the Gothic manner, and thus rise to the full height of the wider diagonal ribs. Each group of ribs springs from a group of clustered columns. Externally the columns and vault are supported by stout buttresses of semi-circular plan. Unlike the Lower Church, the transepts also have ribbed vaulting.