Description
The surviving building of Thomaston Castle stands on a slight natural mound, and there is evidence that shallow ditches may have been formed around it, albeit more in the interests of drainage than of defence. Presumably built towards the mid-sixteenth century as the residential core of the castle, it represents an unusually sophisticated variant on the tower house theme, in which the accommodation is more laterally extended than was usual aIthough it is of basically L-shaped plan.In the re-entrant angle between those two elements is a square stair tower, with the entrance at its base. A particularly unusual feature of the plan is that the entrance to the main courtyard, which was to the south of the surviving building, is by means of a transe through the wing, and there are traces of the courtyard wall and of a lean-to building against the south face of the wing,
The ground floor was divided into a series of vaulted chambers containing the kitchen and other offices: four chambers in the main block and a fifth in the wing; a mural service stair runs up the south wall. At first-floor level there was evidently a principal lodging consisting of a hall and outer chamber in the main block and an inner chamber in the wing. All were heated, and there were mural closets in the hall and inner chamber. The pattern of the windows shows that the second floor was more subdivided than the first floor, with some of the partitions being thus presumably of timber. There was presumably also a garret, though nothing survives of that. The more important openings and the hall fireplace are framed by roll mouldings of varying scale, while the wall-head parapet was carried on continuous mouldings of a type that is most frequently found in this area, as at Law and Stanley Castles. Built into the gable wall of one of the adjacent estate buildings is a lintel stone decorated with a depressed ogee arch, which presumably originated within the castle.
History
Traditionally the castle is said to have been built for Thomas Bruce, a nephew of Robert I, though nothing now on the site can be so early. The existing building was probably built for the Corry of Kirkwood family, whose association with the site is established by charter evidence from 1507, though wide-mouthed shot-holes along the more exposed north face suggest a date of construction no earlier than the second quarter of the sixteenth century. By the mid-seventeenth century the estate had passed through marriage to the McIlvane of Grimmet family. In the earlier eighteenth century the heir to that family, who was resident in the castle, was factor to the Kennedys of Culzean. It was later absorbed into the Culzean estate, and the adjacent coach house and kennels were built in 1793.
Status
The main building of the castle is externally largely complete to the wall head, though there are major fissures and an area of collapse in the east wall; the parapet and gables of the roof are entirely lost. Internally, the vaults over the ground floor partly survive, though the chambers at that level are inaccessible because of fallen masonry and the vaults have collapsed at a number of points, as has the principal stair. None of the cross walls now survive above ground-floor level. There is extensive infestation by woody vegetation, some of which is exacerbating the damage to the masonry. Nothing visible remains of the south courtyard, apart from traces against the south wall of the wing, though parts of its perimeter wall and of the buildings within it were encountered in the course of excavations in 1997, when a pipe trench was being cut.
Conservation Options
The completeness of the shell of the castle, taken together with the surviving evidence for its internal planning and fitting out, means that it would be relatively easy to re-establish the details of its original form with a high degree of certainty. However the castle is a substantial building and is in close proximity to a group of working estate buildings.
Bibliography
Close, Rob, Ayrshire and Arran, an illustrated architectural guide, Edinburgh, 1962, p. 172.
Discovery and Excavation in Scotland, 1998, p. 87.
MacGibbon, David and Ross, Thomas, The castellated and domestic architecture of Scotland, vol. 3, Edinburgh, 1889, pp. 289-91.
Moss, Michael, The magnificent castle of Culzean, Edinburgh, 2002, pp. 25-26.
Tranter, Nigel, The fortified house in Scotland, vol. 3, South-west Scotland, rev. ed., Edinburgh, 1986, pp. 70-71.