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In order to keep a major historic building in good repair it is essential to have accurate plans and elevations in order for the architect to specify repairs or conservation work This is especially important at Norwich Cathedral because of the proposed new Visitors’ Centre. Before the new building could be designed the existing historic fabric had to be carefully measured so the design architects knew all the relevant dimensions.



This was the stimulus for a measured survey. Initially it was only the cloister that was surveyed, as this is at the core of the new buildings, but after this was judged a success the project was extended to the whole cathedral. This meant producing plans of the building from the below ground heating rooms and basements, right up to the galleries and roof. It was a huge undertaking, just measuring the stone floor took weeks as each corner of each floor flag was carefully measured, and there are around four thousand of these.

After two years the survey was complete. It was the first survey of The Cathedral in two hundred years, and the first modern survey of any British cathedral. English Heritage hailed it as a role model for other cathedrals to follow, and more importantly it has played a key role in the upkeep of the building, from floor repairs to fire detection. All the plans are on CAD (Computer Aided Drafting); it is possible to “zoom” in on different areas, and print off parts of the building to scale. The information is all on CD ROM, which means the architect can study the building from the comfort of his office. This project was jointly funded by English Heritage and the Friends of Norwich Cathedral.

Plans are not the only form of drawing produced. The most obvious recent restoration work at The Cathedral was that on the South Transept elevation (see drawing). Despite being all Victorian restoration, the stonework on the South Transept began to fail in 2000. The more exposed elements such as the string-courses and sills were weathering very badly, and the shafts were cracking due to the expansion of the iron cramps that join them. Repairs were urgently needed, but as the elevation had been little touched since being refaced in the 1800s no scale drawings had ever been made of it. Recording was therefore necessary so as to produce a stone-by-stone drawing for the architect to mark up the repairs. By using a reflectorless laser theodolite the elevation was surveyed by aiming a laser dot up onto the wall; by following the lines of the wall with this laser, the information is stored on a disk which is later transferred to a computer. When an outline had been made by this method, the detail was filled in by taking photographs which could be scaled and rectified.

Once scaffolding was erected a closer inspection was possible. English Heritage asked that a watching brief took place in order to make a record of the stone to be replaced, and to look out for any original mediaeval fabric. Only Victorian stonework survived on the surface, and when the masons started removing some of this it became clear that it was pure cladding, much of it is only a few inches thick. Disappointingly, very little mediaeval stonework was found underneath and there was no sign of the buildings known to have abutted the transept, a contrast to the North Transept which has numerous scars. However, one find was the date 1801 carved into a string-course, which neatly tallies with the documentary evidence; correspondence between the Dean and the architect Anthony Salvin also dates to this time.


A 3D plan of the cloister vaulting has been produced. English Heritage require that cathedrals carry out this kind or recording in advance of restoration so that there is a record of the current state, but there are many other end users; conservators are using the drawings to mark up their observations and suggest methods of preserving the stonework. The drawing (top) shows the result of combining survey data with scaled rectified photographs in CAD
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For information on current projects contact:
Philip Thomas MA AIFA, Clerk of Works Tel: 01603 218 445

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Romanesque 'Piscina' discovered in remains of monastic chapel Campaign News

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