Thirlwall Castle : What the Archaeologists Can Tell Us
Archaeologists worked in close collaboration with the architectural conservation team to explore buried remains within and outside Thirlwall Castle during the conservation work. They also monitored drainage and other works in the wider area.
Thirlwall Castle was rectangular in form and measures 14.2 metres by 5.8 metres. The castle was built largely from re-used Roman stones and is aligned north-east to south-west. Square turrets project from the northern angles and a large rectangular tower occupies the south-east corner. The main structure of Thirlwall Castle seems to have been built to four storeys throughout with the turrets and tower carried higher. The floors were all wooden, as shown by internal set-backs in the wall faces. There seems to be an exception with probable stone vaulting in the north-west turret and basement of the tower.
Unusually Thirlwall Castle seems to be mostly unaltered by later additions or modifications. Also notable is the absence of associated medieval structures and features, either domestic or defensive.
Excavations within and just outside Thirlwall Castle have located buried floors of cobbles and stone flagging, while an excavation on the east side of the castle revealed the lower courses of a wall of two phases in the restricted space between the castle and the edge of the drop to the burn.
Geotechnical works carried out beneath the known archaeological stratigraphy have indicated that much of the mound upon which Thirlwall Castle sits is man-made.