Saturday, 30 December 2017

How did they do that!


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Many of us who watched Carols from Kings on Christmas Eve, must have wondered how on earth its mid 15th C builders managed to construct that amazing fan vault ceiling; and why it doesn't simply fall down. The chapel's fan tracery ceiling is the world's biggest, and was completed in 1515.

It's the 'close to horizontal' form of the ceiling that baffles the viewer. It seems almost impossible that all that weight can remain in situ.

Such a ceiling relies on a few basic essentials. Extremely solid exterior walls (probably with ordinary, or flying, buttresses), extreme accuracy from the stonemasons themselves, and plenty of weight from above. The medieval stonemason would have known the process, but not the theory behind its success.

The process is roughly as follows. Once a very solid wooden template had been constructed, the main cross ribs were placed in position from one side to the other, and secured with a key stone; these were quite solid and stable. Then the major inter-connecting ribs were added, and the huge keystones (bosses) secured to hold everything in place (the decorative bosses at Kings weigh about 1,500 kilos each). Only then can the decorative infill begin, using all the other solid ribs as support; sand would probably have been used to hold-up the exact positioning for the newly laid stones. Eventually when all was in position, several tons of stone rubble was placed on top to create a huge downward force, and (hopefully) secure everything in place.

During the whole process, the stonemasons would have seen nothing of how the finished job would look from below.

It is claimed that the wooden template was often burned away to reveal the ceiling in all its glory, as the builders stood back with fingers crossed. It certainly would have been a very tense moment.

So, when you next look up at some vaulted fan tracery, I hope you will be like me, and marvel at the skill of the medieval builders who managed to do all that with just hammer chisel rope and a lot of prayer.



23 comments:

  1. I also marvel at those ceilings! I read Ken Follet's Pillars of the Earth, it's about the building of a cathedral with very good descriptions.
    Greetings Maria x

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    1. Everything involved in medieval cathedral building is quite remarkable. Once you start looking at them with the eye of a builder, they become almost unbelievable.

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  2. I don't always praise architects, but clearly there were some pretty good ones so many centuries ago.

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    1. I see these buildings as giant Chinese puzzles. Extremely complex, and almost impossible to design.

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  3. Having spent a most of my working life in the construction industry, I look at these structures with awe, never ceases to amaze me how they managed to build such huge projects with such precision and detail in the days of nothing but muscle power and basic hand tools.

    Agree with your comment, almost unbelievable.

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    1. Having been involved in very simple stone cutting, I know how difficult even a small basic window opening can be.

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  4. I wonder how many of those medieval builders lost their lives at work? I remember doing a tour of the spire of Salisbury Cathedral and felt quite dizzy just looking down at the deep troughs of the vaulted ceiling. That was before we even started climbing the spire.

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    1. I think a lot lost their lives; a bit like the Pyramid builders. It must have been the most dangerous occupation of the time.

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  5. Absolutely astounding. But then I suppose they had a lot of time on their hands in those days to learn such skills, no TV or internet to distract them! It's even more astounding to think of all the other things they DIDN'T have in those days.

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    1. A good stone cutter had a job for life (if he survived).

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  6. There was an interesting programme on a year or two back about the building of the cathedrals. They did not always get it right first time and there were several substantial collapses. Ely Cathedral ceiling actually catastrophically collapsed once if not twice during construction even at the point when it was considered finished. They picked themselves up, brushed themselves down and started all over again, as they say.

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    1. Gosh, I didn't know that about Ely, but I'm not surprised. I do remember people saying that no-one understood quite how the 'Octagon' stayed-up. There seemed no logic to its construction.

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    2. I was going to add that a fair number failed...and we don't learn about them much, when we could learn from their failures

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    3. It stop people attending services, if they thought the ceiling could collapse at any moment!!

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    4. insert 'could' between It and stop.

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  7. You missed out one vital detail of the construction. Before they took the woodwork down, they covered the stone vaulting above with a thick layer of mortar for downward compression weight. There is about 6 feet of stuff in the loft space up there.

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    1. I said 'several tons of stone rubble was placed on top', but it's much the same principle. Out here with simple vaulted ceilings, they used sand.

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    2. Oh sorry. I wasn't paying attention.

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  8. I watched the same program as Rachel and it was interesting. I am always fascinated and amazed and humbled when I set foot in any Cathedral. It really is the magic of history.

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    1. I've been thinking about them a lot recently. Real treasures on our doorstep.

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    2. Me too, as I said at Christmas when I visited Norwich Cathedral, all here on our doorstep.

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  9. Every year, when I watch Carols from Kings I am just as enthralled by the architecture as I am by the beautiful singing - and by the way they compliment one another.

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    1. I've only been inside on a couple of occasions, and I spent the entire time looking upwards. An amazing building.

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