2021:586 - Newcomen House, Cork Street, Dublin 2, Dublin

Archaeological monitoring was carried out of 7 investigative engineering trial pits as part of proposed refurbishment works to Newcomen Bank, Castle Street, Dublin 2. The results of the site investigations will inform the design.

The Rates Office, former Newcomen Bank, is one of Dublin’s finest eighteenth-century buildings which enjoys a unique setting on Cork Hill opposite City Hall at the entrance to Dublin Castle.  Designed by Thomas Ivory in 1781, the former Newcomen Bank’s last use was as the rates office. The original building was half the size of the current structure – Ivory’s original design has been mirrored, and a new portico added to link the two halves together.

In the mid-1990s, Martin Byrne (Arc-Teck) completed two large-scale archaeological excavations on adjacent sites at Nos 20-25 and 26-29 Castle Street. The excavations produced remarkable archaeology with stratified deposits up to 3m in depth. Several building levels containing the well-preserved remains of at least 20 post and wattle buildings and associated features were identified within the stratigraphy. The site also produced three silver coin hoards which dated the earliest buildings to the 10^th century.

Similar stratigraphy and structures would have extended eastwards and possibly beyond the site of the Newcomen bank. The trial pits indicate that most of this stratigraphy was excavated and removed from the site during the basement construction of the Bank building in 1781 and again in the later extension built in the 1880s. The new bank building probably required deeper and a more extensive basement levels to provide secure bank vault rooms.

The present Newcomen basement floor levels are located at a depth of between 4m (Castle Street side) and 3m (Cork Hill side) below the present street levels. The trial pits revealed post-medieval material including old basement floor levels (clay), clay deposits and wall foundations/footings associated with the construction of the bank. The exception to this was in pit B3 where a black organic deposit was located at a depth c. 0.75m below the basement floor or up to 4m below the present level of Castle Street (estimated depth). This organic deposit is typical of the type of material associated with Dublin Viking Age levels. No dateable artefacts or pottery were recovered from it but it most certainly dates to at least the 13^th century and probably earlier. Further archaeological investigation in this area may be required to ascertain if this deposit is associated with post and wattle structures or a fill deposit of a cut feature such as large pit or boundary ditch.

The upper levels of the natural clay or subsoil was located at depths of between 0.4m to 0.7m below basement floor slab.

In summary, archaeological material is present below the basement floor slabs. This material dates from the 10-13^th centuries (at least 0.3m deep) and from the late 18^th to 19^th centuries (maximum depth of up to 0.5m).  Depending on the nature and extent of the planned refurbishment works, more extensive archaeological testing may be required.

ACAS 45 Richmond Park, Monkstown