Event/Activity EPM100 - Archaeological Watching Brief at 90-102 High Street, Portsmouth

Southampton Archaeology Unit carried out a watching brief on three test trenches excavated to ascertain the cause of subsidence along the pavement at 90-102 High Street, Old Portsmouth. The trenches were just under 4m long, 0.6m wide and 1m deep, and were dug mainly through the pavement, although 1m of each extended into the grounds of the Cathedral. The investigations showed that the subsidence in the pavement was due to the backfill of cellars belonging to demolished houses, which had begun to subside. The southern walls of the cellars were observed in all three trenches, and the backfill excavated. The backfill at the southern end of the cellars was made up of soil and brick rubble, which contained several 19th-20th century finds. The backfill at the northern end (nearest the Cathedral) consisted of soil containing 19th-20th century finds, and fragments of human bone. Internal walls were only observed in the western most cellar. The backfill of the cellars was not compacted, and contained fragments of large wooden beams. It was thought this would subside further if left. Accession number: 2009/181