Phase SI were asked by our client to scan several footways to locate, and determine the extent, of cellars that extended under the footways. Several entrances to cellars were visible in basement courtyards next to the footways, bricked up former entrances could also be seen and there was potential that other cellars could be present whose entrances had been covered. It was decided to utilise ground penetrating radar (GPR) to determine if additional cellars were present and if possible to confirm their extents.
Sometimes GPR data can be difficult to interpret but in this case the results were unambiguous and we were able to plot the location and define the extents of a series of cellars underlying the footways. The known cellars had stone arch ceilings and these were clearly identified by the GPR survey and in the majority of cases it was also possible to determine how far the cellars extended under the footways.