2011:351 - CASTLETOWN HOUSE AND DEMESNE, CASTLETOWN, Kildare

Castletown House and demesne in Celbridge dates from the early 18th century. Since its acquisition by various charities and organisations in the 1960s and ’70s, and most recently by the government in 1996, the building and its grounds have been undergoing continuous conservation works. The Office of Public Works required archaeological investigations at Castletown in order to inform a conservation/restoration project of structures, paths and planting schemes within the gardens. Archaeological investigations were carried out in five areas over two weeks in August 2011.

The sites investigated are all located to the south of the house and consist of the bathing house, Mrs Siddon’s Temple, the mound and the ice house, with a fifth area investigated towards the end of the excavation period to expose the buried extent of the bridge wall.

Area 1—the bathing house

This small building is located along the north bank of the River Liffey and is thought to date from around 1778. It survives as a stone and mortar ruin measuring 4.2m north-east/south-west by 3.4m externally, with an opposing window opening at both the west side and the east side, a doorway within the south wall (facing the river’s edge) and a small fireplace within the north wall, the flue of which is visible within the eastern gable. Seven trenches were excavated within and around the perimeter of the bathing house and evidence was found to inform the restoration design for this building.

The roof of the bathing house would appear to have been constructed from blue slate tiles, each measuring 0.3m by 0.15m by 4mm thick. The roof may have been finished with red clay ridge tiles, small fragments of which were also recovered. Full dimensions of these tiles were not possible to obtain, as only fragments had survived, though they were 15mm thick.

The floor seems to have been surfaced with plain, red, square clay tiles. No complete tiles were recovered to give exact dimensions, but they were 15mm thick. Although no tiles were found in situ, the level of this floor is suggested by the mortar deposited above the stone foundations along the eastern window, together with the line of render along the interior of the walls, the level of the hearth and the threshold evident at the doorway; this gives a level of 43.86m OD.

The render surviving along the interior of the north wall appeared to have been applied very thickly, possibly in two stages (the base layer being very rough), which may have had some connection with the location of the fireplace at this side of the building, requiring a thicker layer of render than elsewhere (on average 20mm thick). There were indications that the interior of the building was adorned with decorative plasterwork, which was evident as fragments of possible coving and door surrounds. Unfortunately, no plaster fragments were found within the trenches excavated outside the building to confirm whether the exterior had been decorated with stucco.

The fireplace had been backed with red brick and the hearth constructed from stone. The stone base of the hearth may have been surfaced with a thin, rectangular slate slab measuring 0.45m by 0.3m by approximately 3mm thick. This was found to the south-east of the fireplace and may have been displaced from it. A small fragment of ceramic wall tile was also found adhering to the edge of the fireplace opening, which would indicate that the surround was decorated with white-glazed wall tiles. Further small fragments of these tiles were found within the deposits excavated inside the building. Although no complete tiles were found, they did measure 7mm thick.

Fragments of thin, clear window glass, only 1.2mm thick, were detected and are likely to have come from this building. .

Outside the building, along the riverside, the remains of a stone path and associated steps were identified to the south-west,just over 3m south-west of the centre of the doorway. If it had once led directly from the doorway the evidence for this has since been removed or perhaps lost to the river. The stone path may originally have continued along the façade of the bathing house. Faint traces of decayed stone were noted 0.6m south-west of the doorway, and to the east was a thin mortar spread.

The stone path is narrow, 0.5m wide, consisting of thin stone slabs set into a thin mortar bedding. As uncovered, it ran in a straight line north-east/south-west for approximately 1.6m, at which point it turns south towards the river, where there are three stone steps, wider than the path and leading down to the river’s edge. Only three steps were evident, all slumped southwards. If further steps had once existed, they may have slipped into the river.

The trench excavated outside the northern wall uncovered some evidence to suggest the edge of a compacted clay surface, which has been interpreted as a possible path running roughly east–west alongside the bathing house. The trenches opened up alongside the southern and eastern walls to investigate the peculiar niche in the south-east corner of the building did not reveal any evidence to confirm its function. Furthermore, no evidence of external stucco was detected within the trenches along the perimeter of the structure. No previous planting other than recent root activity was noted.

 

Area 2—Mrs Siddon’s Temple

This structure is round; half of it is open, with regular rounded columns, and the remaining half is closed. It sits on an artificially created mound. Six trenches were excavated radially around the temple, each 1m wide and up to 6m in length.

A single step associated with the temple was identified directly alongside the base of the structure, providing a step directly up into it and extending the perimeter of the open side only. This stone and mortar step was 0.34–0.44m wide and had been constructed up against the stone and mortar foundations of the temple. No further stepped terrace was indicated in the area excavated around the temple.

The roof would appear to have been covered with blue slate tiles, given the fragments found across all of the trenches excavated. These fragments were found within deposits apparently relating to the temple’s falling into disrepair. No complete tiles were found, but it is thought that they would have been a similar size to those indicated from the bathing house, each measuring 0.3m by 0.15m by 4mm thick.

Fragments of render recovered within the excavation trenches indicate the wall finish. Again these fragments were found along with slate fragments, within deposits that indicated a time of neglect when the temple began to fall into a ruinous condition. Fragments of render were also found that are most likely to have come from the columns of the temple structure, as they had a curved profile.

The test trenches revealed the build-up materials making up the mound upon which the temple was constructed. These comprised dumped deposits of large lime mortar fragments and heavy clay. No evidence of a path surface or planting was detected within the excavation area.

 

Area 3—the mound

This site may have formed part of the terraced gardens depicted on the 1760 Rocque map but altered some time thereafter, as a small building is then indicated to stand on this site from about 1765 to 1840.

A possible wall detected in a previous phase of archaeological investigations was relocated and on further investigation has been interpreted as either a rectangular foundation wall to facilitate a small structure or a plinth for a seating area. The feature was constructed from stone and mortar and measured 3.5m north–south by 1.4m; its uppermost level was only 0.12m below current ground level. The masonry has defined edges on all sides, with no indication of a return. The plinth is sited perfectly on the mound to afford a view of the river (particularly the cascade) for whatever type of structure lay above it. It would seem the perfect base for a seating area to enjoy this vista. Imprints along the eastern edge, facing the river, suggest that there were once stone slabs set into the mortar, providing a step or edging to the plinth.

A 2m-wide zone was stripped around this plinth, which subsequently uncovered a gravel deposit leading from the west-north-west and continuing east-south-east. This is interpreted as a possible path leading around the top perimeter of the mound and along the front (eastern side) of the plinth.

Further trenches were excavated to assess whether surviving remains of an earlier structure could be located where the geophysical survey had indicated. The deposits picked up in the survey that had indicated possible structural remains proved, however, to be a dumped deposit of stone, mortar and red brick rubble. This deposit had been tipped, amongst deposits of clay, to build up the mound and increase the height of this landscape feature.

 

Area 4—the ice house

This is a circular domed structure with a long access passage opening to the south-west. It was constructed primarily of stone and mortar, while red brick was used to construct the dome. The entire structure would have been buried under an earthen mound.

A small box section was excavated to the rear of the ice house, at a partially collapsed section of the structure but also where some of the mound material was still in situ. Removal of only 0.16–0.38m revealed a stone surface of flat, regular slabs, which had been placed tight against the original wall of the ice house.  This surface was recorded and left undisturbed.

 

Area 5—the bridge

The objective for this area was to follow the line of the existing stretch of bridge wall located along the eastern side of the bridge that spans a stream to the south-eastern side of the house and to expose the buried remains. The bridge provides access along this main avenue in front of Castletown House.

The stone and mortar wall was found to survive to varying heights, 0.15–0.75m below current ground level. It measures 0.46m wide and a section of 8m was exposed, revealing that the end of the wall had been truncated by the insertion of a manhole at the northernmost point.

Archaeological Development Services Ltd, The Print House, South Cumberland Street, Dublin 2