St Mary's School House is a freestanding, two storey building, oriented east-west in Carew churchyard.
Called the 'school-house' in 1625, and used as such until 1872, the building was also a possible mortuary chapel, the vaulted undercroft being an ossary, possibly dating from the early 14-15th century. There is a large, blocked window, showing the remains of tracery visible in the east wall of the upper storey.
The building's last recorded use was as a commitee room and store, possibly later converted for residential use (after 1872?).
