Long Term Worries

Over this time the buildings were subjected to much repair, renovation and alteration and we know, as did our forefathers, of the value of constant maintenance and the dire consequences of its omission. We have records of many of these campaigns of repair and alteration and it is fascinating to find that many of our current concerns are merely the continuation of worries of the past generations.

I have personal experience of two very clear examples of such ongoing concerns, one which, so far, has required no intervention, but a second which resulted in significant works.

The retro choir at Wells Cathedral is a vaulted area between the high altar and the Lady Chapel, the supporting columns are very slender and support an unbalanced vault onto which are imposed large loads

Figure 3. Chichester spire collapse.

from flying buttresses. On visual inspection one is immediately worried that the vault is in tension and that the slender columns are undergoing excessive bending.

I have investigated these carefully and can show that they have a factor of safety greater than 1.0 which is just as well as they have been standing unchanged for 900 years. On searching back through the archives I find that every Cathedral Architect, Engineer, and before that the master masons, were all expressing concern about the retro choir and all setting up their own monitoring systems - just as I have done! Indeed the Victorians had a series of specially fabricated props which were kept close to the retro choir for instant installation if any cracks appeared. My own advice is that if cracks appear everyone is to run, as there will probably be localised and fast compression failures! It gives one a profound sense of historical continuity to find that we share the same worries as our forbears.

Another fascinating case is that of the Deans Eye window at Lincoln Cathedral. This is one of the top five rose windows in Europe with fabulous 1220 stained glass and a very ambitious form.

The companion window, the Bishop Eye collapsed within 50 years and the archives show a long history of repairs to the Deans Eye, some successful and some a failure. A constant theme in Clerk of Works records over the centuries is how to keep the window stable. This was initially by adding cramps and lead filling to the joints as they moved, then by bracing across the central opening and latterly by adding major cross bracing behind the window. Until by the year 2000 no

Figure 4. Wells Cathedral retrochoir.
Figure 5. Deans Eye window before restoration - Lincoln Cathedral.

more patching was possible and replacement was the only option. A complete reconstruction of the stone tracery was required and the opportunity was taken to include some hidden strengthening so that the internal and external cross bracing which had disfigured the window was no longer needed.

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