2013:527 - St Patrick's Cathedral, Cathedral Close, Dublin 8, Dublin

St Patrick's Cathedral, Dublin (Protected Structure 6443, 6444) is undergoing a major upgrading of services and this report refers to the installation of a new water-pipe along the southern side of the cathedral (at the eastern end), running parallel to the building before turning into the cathedral into a pre-existing conduit. The works required the excavation of a trench, measuring on average 0.3m in width by 0.6m in depth. The pipe was laid in a narrow sunken passageway that runs along the base of the cathedral, and which is revetted in stone along the southern side. The passageway is flagged in stone and some of these were removed to facilitate the new trench. These were found to be of fine sandstone, varying in size from 0.3m square to 0.38m by 0.55m. They were neatly laid in rows, orientated north-east/south-west, and were bedded in off-white mortar, laid through dark brown organic clay, which contained 19th-century brick. The flags were photographed, then numbered and replaced after the works were completed.

The monitoring works located the remains of a cement deposit at the eastern end, where previous services had been built, while the western end of the trench ran along a pre-existing ceramic pipe. The deposits beneath the surface confirm the sunken passageway was constructed in the 19th-century restoration works, to restore the full proportions of the cathedral but also to provide access on this side. The sequence was as follows:

West end
0.00m - 0.1m: Flags
0.1m - 0.6m: Conglomeration of stones, concrete pebbles and granite.

Middle
0.00m - 0.1m: Flags
0.1m - 0.38m: Dark black stony mix containing lenses of silt. It contains shale, rubble, limestone (calp) and mortar (but no brick) and sealed a modern ceramic pipe.

East end
0.00m - 0.1m: Flags
0.1m - 0.43m: Dark black stony mix as above. A fragment of human leg bone was recovered from this deposit, which sealed the ceramic pipe.

Ope in main wall
A section of the limestone facing in the external south wall of the nave was removed to facilitate the insertion of the pipe. This was taken out block by block in an area measuring 0.85m in height (from present flagstone level) by between 0.12m and 0.22m in width. The blocks measured 0.25m in depth. The wall of the water-font within the chapel of St Anne was exposed as the wall was only 0.35m in depth at this point.

Offset
The base of the limestone facing of the south wall of the nave has a projecting offset measuring 0.25m wide by 0.3m (minimum) in depth, the top lying 0.6m below present ground level.

28 Cabinteely Close, Dublin 18