York Historic Environment Record

Tower 2 (NG 60235120.) is semicircular, 16⅓ ft. wide and projecting 7 ft. 2 ins. in front of the wall. There is a double chamfered plinth around the base where footings are visible. It is not bonded into the wall, which is on a slightly different alignment from its inner face.
http://www.british-history.ac.uk/rchme/york/vol2/pp90-107

2019 Test pits suggested a combination of shallow footings the tower and the wall combined with the rubble infill of the tower have contributed to structural movement. Concrete underpinning was noted in one test pit suggesting that the subsidence is an historical issue.

In 2021 the Victorian parapet wall was carefully removed due to structural movement and cracking. The wall was then rebuilt and strengthened. This work provided insight to the sequence of events, from the construction of the rampart to all stages of Tower 2 construction and renovation.
In summary, It is likely most of the structure below the previous extant floor level is related to the original construction of the tower in the early-mid 14th century (RCHME, 1972), with several
repair and remodelling events from that date to the early modern period. Everything above and including the current walkway is nineteenth century and later in date (YAT 2021).

RCHME, 1972, An Inventory of the Historical Monuments in the City of York, Volume II The Defences, p91 (Monograph). SYO63.

YAT, 2019, Tower 2 City Walls EVA (Unpublished document). SYO2444.

Mason Clark, 2020, Tower 2 Slope Stability Analysis (Unpublished document). SYO2443.

York Archaeological Trust, 2021, Tower 2 City Walls EVA and WB (Unpublished document). SYO2668.