A Ground Penetrating Radar (GPR) survey was conducted at Kirby Hall to investigate the immediate vicinity of a collapsed flagstone in a small storeroom adjacent to the Great Hall. The GPR survey was conducted in response to a request from the English Heritage Trust following a particularly wet winter that led to the flooding of both the Great Hall and a small adjacent storeroom. The floors in both rooms are constructed from suspended flagstones and an isolated area of collapse appeared following the flooding event in the storeroom. It was hoped that GPR survey within the storeroom would help to identify the size and nature of underlying void in advance of works to address the flagstone collapse. The survey was extended to include the Great Hall within the main building to determine the location of any further possible voiding, and also over the south lawn to investigate the complex pattern of drainage known to exist here. A 3d-Radar MkIV GeoScope Continuous Wave Step Frequency (CWSF) Ground Penetrating Radar (GPR) system was used to conduct the survey collecting data with a hand operated multi-element DXG0908 ground coupled antenna array inside the building and a vehicle towed DXG1820 in the external areas. A Trimble S5 tracking total station and active reflector prism mounted on the GPR array was used to provide continuous positional control for the GPR data collected within the building interiors and the external areas surveyed with control points for the total station established using a Trimble R8s Global Navigation Satellite System (GNSS) receiver adjusted to the National Grid Transformation OSTN15 using the Trimble VRS Now Network RTK delivery service. A combined area of 0.4ha was surveyed with the data from within the storeroom suggesting the voiding in the immediate area of the flagstone collapse is relatively localised. Areas of high amplitude response within the Great Hall may require further invasive investigation to determine whether this remains structurally sound. Results from the South Lawn corroborate the previous earth resistance survey and suggested some additional detail associated with possible structural remains.