The original hammerbeam roof was removed in 1800, along with the decorative crenellated parapet, when the hall was subdivided to form barracks. Two floors and five cross-walls were inserted, and the windows were altered accordingly. As early as 1893, calls were being made for the restoration of the Great Hall, but it was not until the army left in 1965 that the opportunity arose.
It was agreed that a historically correct restoration could be achieved, and works began which were only completed in 1999. The hammerbeam roof and parapet were replaced, windows reinstated, and the outer walls were limewashed.
Green oak from 350 Perthshire trees was used to fabricate and erect 57 hammerbeam trusses spanning approximately 15 metres. Since its construction around 1502 by King James IV of Scotland, structural loads from the roof had caused the walls of the hall to deflect outwards. To ensure that the ridge of the roof would be level and straight, the trusses were each made with a slightly different pitch and span. The restoration started in 1991 and was completed in 1999.
Other examples are in the Parliament Hall in Edinburgh, the Great Hall in Edinburgh Castle, the chapel of New College Oxford, the Great Hall of Athelhampton House, Dorchester, Dorset and the Great Hall of Darnaway Castle in Moray, Dartington Great Hall Totnes, Devon.
On the east side of the Inner Close is the Great Hall, or Parliament Hall.
This was built by James IV following on from the completion of the King's Old Building in 1497, and was being plastered by 1503.
Described as "the grandest secular building erected in Scotland in the late Middle Ages", it represents the first example of Renaissance-influenced royal architecture in that country.
It was worked on by a number of English craftsmen, and incorporates some English design ideas, being comparable to Edward IV's hall at Eltham Palace, built in the late 1470s. It includes Renaissance details, such as the intersecting tracery on the windows, within a conventional medieval plan.
Inside are five fireplaces, and large side windows lighting the dais end, where the king would be seated. It is 42 by 14.25 metres (137.8 by 46.8 ft) across, making it the largest such hall in Scotland.