SDO14978 - Portland Castle, Portland Bill, Dorset. Report on Geophysical Survey, November 2012

Report on a ground penetrating radar (GPR) survey carried out in November 2012 by Historic England’s remote sensing team to assist in the investigation of water ingress through external walls into the Captain’s Chamber. Survey was done over the face of the external walls from a two-tier scaffolding platform, and results confirmed sufficient penetration to provide useful information. Anomalies were recorded that related to the varying thickness of the outer wall and the location of known defects such as timber sockets visible from inside. Further defects in the structural integrity of the wall were suggested including an area below the string corbel and areas where there were corroded ferrous fixings.