2019:681 - St Patrick's Cathedral, Dublin, Dublin

A monitoring programme (Phase 1) was carried out at St Patrick’s Cathedral, which is currently undergoing a large-scale restoration project under John Beauchamp, Conservation Architect. This includes the replacement of the roof, which required the erection of a robust scaffolding and a tower-crane, a challenge due to the heritage constraints of the site. The scaffolding structure was carefully designed to have the little impact on the ground, the scaffolding struts bedded on a layer of compacted 804 stone with the cathedral façade protected and boxed-out where necessary. A series of small test-pits, 19 in all, were carried out around the cathedral, before the erection of the scaffolding, which were designed to establish the depth of sod or topsoil, found to be a consistent 0.35m in depth. The testing indicated that the general topsoil, north and south of the cathedral, contains tiny fragments of human bone, as expected. However, no articulated remains were found at this high level. The testing also established there is some sort of concrete surface in some areas, presumably put down during the restoration in the 19th century.
After the testing, the topsoil was stripped off mechanically, both north and south of the Cathedral and a layer of 804 stone was laid (300mm in dpeth) and compacted, to provide a solid foundation for the scaffolding.
The testing also revealed the presence of two Early Modern tanks, one replacing the other, in the eastern angle of the North Transept, which was a fortuitous find. The larger replacement tank had almost completely removed the earlier tank, the former found to be constructed of concrete and brick and identifiable as a water tank that powered the organ for a brief period. The tank was identified as a relatively good location for the crane base, which could reach most parts of the cathedral. In addition, as the main tank was 3m deep, it had effectively removed any potential archaeological deposits in this area. The removal of the large concrete and brick tank was monitored and recorded, as was the construction of the crane base itself, which was of concrete. Parts of the tank were left in situ as part of this process.
During the testing for the crane-base a limestone wall was identified to the north-east of the North Transept, lying 0.3m below present ground level and running roughly east-west (but slightly angled). This can be identified as a mid-18th-century boundary wall (marked on Francis Grose’s map of the cathedral c.1750), which originally ran from the north-east corner of the North Transept eastwards along the length of the cathedral at a time when dwellings abutted the cathedral directly on this side. The wall measures 0.7m in width and is composed of large limestone blocks, measuring, on average, 0.3m by 0.4m, the facings of which are set on edge rather than flat. Only the northern side was exposed and this extended to 1m in depth, founded on yellow clay. On inspection the wall was found to have a rubble core, which was mortared with creamy yellow lime mortar. This boundary wall was carefully resealed and was not impacted on during the works.
West of the North Transept a graveyard is depicted on Rocque’s map of Dublin dated 1756 and burials, disturbed when the boiler house was put in the 19th century, were found. However, this area was not impacted on during these works.
The repairs to the roof have also provided access to the interior where repairs are being carried out to the various joints, under the direction of the Conservation Architect. This forms part of the Phase 2 works which are on-going.

28 Cabinteely Close, Old Bray Road, Cabinteely Dublin 18