The quality of its vault is very high: the blocks which constitute it have been cut jointed and fitted with care to form a semi-circular cradle with perfect regularity. The vault was reinforced, in the middle of the building, transversely, by a double arch, today torn off, which rested on two consoles; one of them is preserved, protruding from the north interior wall. Its actual conditions are worrying, although a provisional propping has been put in place after a mission of Europa Nostra in 2016.