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Tuesday, May 31, 2011

Great Designs in Wood (13)

You may recall the Maypole Inn story that we covered in GDiW(10). There's another great story of wood construction in England that occurred at roughly the same time, and on a much larger scale.


Westminster Hall is the oldest building on England's Parliamentary estate. In and around the Hall, grew up the major institutions of the British state: Parliament, the law courts and various government offices. But it's history is richer than just a gathering place for Britain's political elites. For instance, the Hall was used as an early modern shopping center, and as a drilling station for troops during 1859-1861 as Britons awaited invasion from the French of Napolean III. In 1833, Charles Dickens, having for the first time seen one of his stories in print, walked around Westminster Hall for half an hour with his eyes "dimmed with joy".


And as he looked up, he would have been gazing at the largest medieval timber roof in northern Europe. 


http://www.flickr.com/photos/uk_parliament/sets/72157606364068829/



Measuring 20.7 by 73.2 meters (68 by 240 feet), the roof was commissioned in 1393 by Richard II, and is a masterpiece of design.  The court's chief carpenter Hugh Herland 
http://www.flickr.com/photos/uk_parliament/2700357021/


"...fashioned great oak beams to serve as horizontal supports fixed to the walls (which chief mason [Henry] Yevele strengthened by massive buttresses). Wooden arches joined to the top of these beams met centrally in a span of 18 meters (60 feet) or more. 
Onto these arches the craftsmen built the slopes of the roof, with its weight borne by the hammer-beams supported in their turn by the buttressed walls. 
The construction of the roof was an exceedingly complex and dangerous operation, given the size and weight of the timber and the great heights they had to be lifted to (about 28 metres, or 92 feet). But the result, as we see it after nearly 600 years, is a vast, clear space unobstructed by a single column. 
The roof's timberwork was entirely framed near Farnham in Surrey. A large number of wagons and barges delivered the jointed timbers to Westminster, weighing some 660 tons, for assembly."
 - www.parliament.uk


The roof hasn't been without its maintenance issues.
"In 1913, an inspection of the Hall's roof beams revealed that they were seriously affected by death-watch beetle, so much so that four out of the thirteen trusses were in danger of collapse. 
The wall-posts were almost all useless and some cavities were so excavated by beetles that a full-grown man could lie in them completely hidden from sight. 
Extensive repairs were carried out to the Hall's roof by Frank Baines in 1914-23. The entire roof was reinforced by concealed steelwork, and the decayed portions replaced with new oak from Wadhurst in Kent. 
Baines sought to preserve as much as possible of the original timber (less than 10 per cent was replaced), and even its unique golden-brown colour, which he identified as the result of a harmless fungus.
But he did not manage to eliminate the beetle completely; nor was it achieved in 1971 with canisters of pesticide in the form of smoke."
- www.parliament.uk

And this was after the Hall was damaged by a fire in 1834, during which the primary concern was on dousing the roof with water so as to save the historic old beams.


The roof as designed in the 1300's carried the weight of 176 tons of lead roofing, which has since been replaced by slate.


Age, fire, water, insects, and tremendous load...and still the roof stands as surely today as it did in the 1390's. Another testimony to the enduring quality of great wood design.

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