The ground floor of the building is occupied by a private business. There is no evidence that this was ever an open structure; it seems to have functioned for various types of trading from at least the sixteenth century, and possibly throughout its existence.
 
The present Museum entrance and staircase are of relatively modern date and the upper floors were probably accessed originally from Fisher Street.
 
The open roof structure shows two markedly dissimilar types of construction, although dendrochronological study has revealed that all the timber dates from the time the building was originally constructed. There is virtually no documentary evidence of the construction or early structure of the Guildhall, and the earliest illustrations are of 19th century date. Detailed investigation of the structure of the building has recently been undertaken by English Heritage and Carlisle City Council, and should help to resolve many unanswered questions.
 
The Guildhall is a Grade 1 Ancient Monument, and one of the four oldest buildings in the City. 

More information and details on opening times can be found on the Tullie House websiite here.