Trusting the structure of a masonry dome (you’ve built...)

No matter how much you read about the strength and stability of a dome construction, it isn’t until you actually walk inside something like the Pantheon in Rome that you appreciate the incredible forces involved. Considering that this particular (and huge) Roman dome was built over 2,000 years ago and yet still keeps tons of rock “hanging” above your head without any seeming support is what I consider a miracle of construction. That said, when I cleared out the supporting materials under my WFO’s completed dome I was really cautious/fearful of putting my head into the oven. While knocking that first support out, I actually stood off to the side in case the oven collapsed (after all, I'm not Roman).

Turns out, the structure and design of a dome is something that even someone with no Roman ancestry or masonry experience (such as moi) can create successfully by following a few simple instructions. When I cleared out the sand from the oven chamber, I was struck not by hundreds of falling firebricks but simply by the high humidity of the interior. It didn’t take long for it to sink into my beady brain that the dome was not going to collapse or shift in any significant way. It was an incredible relief to finally believe my oven was really going to work as an oven and not become a final monument to my ineptitude (while doubling as my tomb with the poignant, yet simple inscription, "Here Lies a Dome Builder Who Should Have Stuck With His BBQ").

My plastic covered sand form worked well to help make pretty smooth & consistent angles on the inside of the dome. Just before clearing out the sand trash, I put some thinner concrete blocks along the oven front to raise the outer landing. I needed to raise this area so when I put bullnose bricks on top of them, the bricks would be flush with the inner landing (on the other side of the ash slot). After doing a final inspection & cleaning inside the oven, I started thinking about the building of the front arches for the chimney. In the “putting more than faith inside the oven” picture, note the piece of angle iron across the opening. The bricks forming the outer faux chimney will be laid along this angle iron to get them even & horizontal across the dome's curvature. The actual chimney flue pipe will span the gap between the inner & outer arches while resting on each arch (or so I hope).

As I stood back and collapsed the sand form, I really did
wonder if the structure would remain standing.

As I cleared most of the plastic bags and sand from the oven
chamber, I was pleasantly surprised to note that;
#1 The dome was still intact and #2 The dome inner surface
didn't look half bad...some people might just be polite and
say "Well, it is unique..." 

This is looking up at the dome roof. The bottom
right is pointing towards the front opening.
Again, this short beavertail design of the dome
is most apparent when looking from the top
or bottom of the oven's dome.

It was more than a little intimidating crawling into the oven
  chamber the first time...all the while I was wondering if I'd
applied the mortar properly. Apparently my wife was
thinking, "Well, if we can't afford cremation, I'll
know we can DIY the job here".