The medieval three-storey sacristy , built beyond the east wall of the church and fronting onto Weaver’s Lane was originally the sacristy and treasury of the church. It may have been converted later into accommodation for the priest. Now restored to its original function it contains many original features, including a piscina still used for its original purpose as sacristy drain and a fireplace (now a cupboard) where charcoal for the censers was kindled. The richly inlaid octagonal sacristy table was once the sounding board for the pulpit!
Mancroft possesses one of the five remaining portions of parochial libraries in Norfolk. There are sixteen books dating from the twelfth century to 1763 including a manuscript Vulgate of 1340. The finest books, including the illuminated twelfth century St Paul’s Epistles are held in the Norfolk Record Office (facsimiles are on display in the treasury) while the other books are available to view on request at Norwich Cathedral Library.