Rochester Castle

Investigating Rochester Castle

GBG has been commissioned by Medway Council and English Heritage to undertake a series of surveys to appraise the structure and condition of Rochester Castle Keep, Towers and Mural Vaults. Regarded as one of the finest examples of Norman architecture in England, the Castle Keep measures 113 feet in height by 70 feet square. The walls are 12 feet thick in places.

Simon Curtis, Tourism Manager for Medway Council said: 'At the end of June, the Council is due to receive a comprehensive Conservation Plan for the Castle, which has been prepared by an external consultancy. The information provided by GBG is a fundamental part of this Plan, which will help us to decide whether the Castle should be conserved as a ruin, or whether substantial funding should be sought to significantly enhance it with, for example, the addition of a roof and floors. The castle is already very popular with visitors to Medway. This would have the potential to ensure that the castle continues to flourish and indeed bring in more visitors than ever, making it pone of the country's leading tourist attractions.'

Teams of engineers from GBG used non-destructive testing methods, primarily impulse radar to confirm the existence and extent of voiding within the Castle walls, together with metal detection and visual inspection over the course of several days. They also carried out extensive descaling work, involving the removal of loose stones (both Caen and Kentish Rag) and mortar, carefully noting their location so that they can be replaced at a later date.

George Ballard, managing director of GBG said: 'Based on the findings of our various surveys, we have made a number of recommendations to Medway Council. These include the installation of a rainwater control system to prevent further weakening of the core of the Keep walls, the introduction of crack monitors in the South West Tower and urgent stabilisation of the Mural Vaults.'

Simon Curtis concluded: 'This is the first time that non-destructive testing techniques have been used on the Keep at Rochester Castle. (Previous such surveys have been carried out on the curtain walls.) This approach, combined with GBG's structural engineering appraisal and recommendations, has provided valuable information about the overall condition of the Keep, and the repairs that will be required.'