The Corbeling Process

 

High up in the Sun Roof of the Temple of Imperfections

 

Here's what the opening of the dome looked like when the neighbours came to inspect the construction that had gone on so far. This was just before the two large oculus stones were added to the roof. Rich and Nancy had climbed all the way up the interior wooden scaffolding, and didn't carry any stones with them for us to help finish the roof. That's okay. They were suitably impressed.

Closing in over the dome opening

 

As you can see, the guys standing on the stones already laid over the dome of the Temple of Imperfections are rather nonchalantly perched over a black hole. There was a palatable sense of excitement for everyone as these stones went on. Mark Ricard, was inside the 'hole', carefully helping place the one or two rows of  'preshaped' corbel stones around the opening. You can see how dramatic this latter stage of the dome construction was. 

To spiral or not to spiral

As we built up on the inside of the dome of the Temple of Imperfection Mark noticed a discrepancy in height across the circumference of the courses. We wondered if we had been building in a spiral . 

As we followed our eyes around the top stones it was surprisingly difficult to decide.  It turned out it wasn't a spiral, but it did get us wondering about morphing the coursing at this phase of the coursing of the dome, into a spiral

The spiral has the advantage of not having to do that kind of 'last stone' fitting on each row. The stones are merely added one by one, and next to each other, never leaving any gaps to fill at the joining of each circle

But is it as strong? That is the question.

In the end we decided to continue with circular coursing. We laid the stones along the uneven course, gradually getting thicker, to raise the lower side of the circle , and gradually lower on the other side of the circle, to bring the stonework to level.