The main features of the interior of the chapel are a pointed-arched aumbry at the east end of the north wall, a pointed-arched piscina towards the south end of the east wall, a 'Maltese' consecration cross at the centre of the south wall and the magnificent crown-post roof dated to late 14th or early 15th centuries.
The chapel roof has been the subject of a detailed, dendrochronological study by Howard, Laxton and Litton (1997).This has established that the crown-post roof can be dated to between 1395 and 1405 and is clearly not the original roof of the chapel. This is bourne out by the fact that the collar purlin terminates in the central, blocked, oculus.
The western half of the chapel is now floored with substantial fireplaces on both ground and first floor levels with flues leading into a brick chimney stack of 16th or 17th century date. While the fireplaces and chimney stack probably date from the post-Dissolution use of the preceptory, it has already been suggested that part of the west end of the range was floored from the outset, hence the westernmost lancet of the south elevation only lighting an upper floor. At the time the chapel was taken into Guardianship the flooring extended over its whole length.