Laser Scan Survey at Ruxley Old Church, Kent

In January 2007, AOC Archaeology Group was asked by English Heritage to carry out a detailed 3D survey of the Old Church at Ruxley, Kent, using laser scanning. The flint church, built in the 13th century on the foundations of a timber Saxon predecessor, was dedicated to St Botolph before deconsecration in the 16th century. Several original features of the church survive in good condition, including a mounted piscina and sedilla in the south wall. A grade II listed building and a scheduled ancient monument, the Ruxley church is in line for substantial restoration works as part of an English Heritage-funded project which will transform it from its current function as a store to a commercial use on Ruxley Manor Garden Centre.

AOC Archaeology Group’s laser scanner was used to survey the church from numerous locations inside and outside to produce a point-cloud survey with a net scan resolution of 10mm, a process that took a day and a half. A total station control network was used to accurately locate the interior scans within the exterior, providing a highly accurate and detailed surface model of the building, inside and outside. High-resolution digital photography was also employed in order to provide photo-realistic colouring of the surveyed pointcloud. The result is a highly accurate 3-dimensional model of the building which can be manipulated and interrogated in real time in a digital environment.

Analysis of the survey data highlighted a number of areas of concern for the Ruxley building. Restoration works carried out in the 1970s added several courses to the external walls and altered the pitch of the roof, resulting in the apex of the building’s roof being off-centre. This in turn has caused the north wall of the church to bow outwards significantly. This distortion was not easily visible to the naked eye on site, but with the orthographic view provided by the 3-dimensional data and using live cross-section tools within the point-cloud analysis software the problem was easily identifiable. Detailed scans were also taken of areas of cracking masonry and the eroding buttresses, providing baseline data and the possibility for future assessment surveys. Laser scanning provided an ideal means of recording the current condition of the Ruxley building and a source of analytical data for use during the restoration works.

AOC Project Officer: Dr Graeme Cavers
Client: English Heritage