Council on Tall Buildings and Urban Habitat
 St. Paul’s Cathedral Technical Tour
Conference Technical Tour – The Grandfather of Tall in London
June 13, 2013
Patti Thurmond, CTBUH Operations Manager

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See the report on the 2013 London Conference

LONDON - A fortunate few Conference delegates were able to fully embrace “Height and Heritage” in the technical tour of St Paul’s Cathedral. Led by architect and Cathedral Surveyor Oliver Caroe, this tour provided a unique look not only at the history and structure of St Paul’s, but at how the cityscape of London is still being affected today by this historic icon.
St. Paul's Cathedral, photo by: Mark Fosh
The tour began with a brisk walk up to the Whispering Gallery, where in years past commoners could stand to view services, overlooking the nave of today’s St Paul’s. The first St Paul’s Cathedral was founded in 604 AD. As Caroe explained, the spiritual, educational, and civic life of Londoners all took place here. The last St Paul’s was the largest building in medieval England, longer, taller and wider than today’s.
Whispering Gallery
Clive Cornwell, City of London Corporation, joined in leading the tour. He shared the story of how protected views of today’s St. Paul’s have come about, with the non-negotiable St Paul’s Heights grid (1938) and the eight protected long distance Strategic Views (1991). In the Trophy Room, Mr. Caroe presented the Christopher Wren design of the Cathedral. At age 23, Wren had argued his plans to restore St Paul’s, when just 7 days later, it was all but destroyed by fire. Wren’s great vision and talent were available just when England needed it most. Shortly after being granted the design, Wren commissioned the Great Model, a working pattern, a structural model, and a fund raising tool.
The Great Model, a working pattern, a structural model, and a fund raising tool
In 1694, Wren used the exact same piece of paper from his early work in 1675, to start to draw the dome over the building, trying to work out where the dome’s structural load was going to go. It is an excellent example of Wren’s “bottom-up” design.
The building was completed in fragments, but this single-floor plan of the whole cathedral gives a good view of the overall plan. The Cathedral was intended to give a ceremonial access linked into the streets of London. Delegates enjoy this unique, cantilevered Geometric Stair, as featured in many movies, which brings people into the house of worship from the southwest tower entrance.
The perfect Georgian Library has hardly changed at all since constructed. Completed in 1709, due partly to the additional funding and patronage of Queen Anne, the books in this room were part of the original gift to restore the intellectual heart and spiritual knowledge that was lost in the fire. The group was shown an extraordinary drawing by Wren in 1706, showing the continuing construction of the cathedral. This is the moment when Wren drew the final section of the dome that he actually builds. And in a final thought, he tacked on an extra piece of paper and raised the height of the cupola to 530 feet. The essence of Wren’s genius is that he was able to make very late design decisions and carry them through. This drawing and story are available online.
Wren's drawing in 1706 of the construction of the cathedral
Caroe took the group of delegates to the upper chambers to explain the Cathedral’s structural system, pointing out the brick, stone, wood and iron all used in the construction of the Cathedral. It’s believed that the Great Model may have shown the need for relieving arches, which Caroe pointed out in the floor – two great relieving arches, curved the “wrong” way to help spread the load. Caroe explained how the saucer domes were constructed, as well as the choice of these 56’ oak beams from the Duke of Northumberland.
Relieving arches
Moving up to the Stone Gallery, one can easily observe what the results of careful planning look like in London. Cornwell pointed out the deep wedge of tall building construction in the cityscape where no height limitation is in place, as well as the much lower height development in other parts. A disadvantage is clearly seen as developers build flat tops in order to maximize the development potential of their site, forgoing Victorian gables, finials and crests.
View of London from St. Paul's Cathedral
Many thanks to architect and Surveyor Oliver Caroe, City of London Corporation’s Clive Cromwell, and Laura Chilton of St Paul’s Cathedral for planning and leading such an informative and insightful tour into one of the nation’s greatest treasures. The CTBUH Heights and Heritage Conference delegates were able to move about freely throughout the remainder of the Cathedral to further explore.
Kindly supported/organized by:
Surveyor to the Fabric of St Paul’s Cathedral,
by kind permission of the Cathedral Chapter.