As the work is done, original stonework and construction must be preserved to maintain the historic integrity of the canal.

It is of concrete covering the original stonework.

The lower courses are original Roman stonework, though the upper course with arrowslits is a later medieval addition.

It was investigated by archaeologists but has not been restored, although some of the original stonework and plaster coating is visible.

The fort was reinforced with concrete over the original stonework between 1912 and 1914.

Excavations in the 1970s showed that much of the original stonework remains within the 18th-century defences.

Most of the original stonework was robbed for building purposes during the nineteenth century.

Much of the original stonework and wooden beams can still be viewed today.

During the moves, much of the original ornate stonework has been lost.

Some rooms on the first floor retain their original stonework, such as patterned floors and wall paneling.