Mistakes I Made

The oven is basically done, but if I were to do it again, here are some things I would change:

1. I should have shaped the cooking floor to fit the plan of the dome more accurately.  I laid it down without cutting many bricks thinking everything would be hidden by insulation.  Later, I went back and cut the overhanging bits off with masonry saw.  The hanging over bits made insulating the dome more difficult later.  The floor bricks need to be cut to fit the base template very accurately.
2. Insulation.  The rigid insulation has a butt-seam with the ceramic blanket just above where the cooking floor meets the base of the dome.  It would have been better to overlap this transition by at least 2 inches.  I get some heat loss at this seam.
3. I would add additional insulation to the floor.  3-4" of lightweight concrete or 2" more of ceramic board.  The underside of the slab gets up to 100° overnight.
4. I put aluminum foil in as a vapor barrier, but I think I put it in the wrong place.  I did brick, foil, insulation, vermiculite-concrete, stucco.  I think the foil would be better served between the insulation and vermiculite-concrete, where it would inhibit water penetration into the insulation, and be insulated from the hot brick
5. I would make the opening for the under-oven storage area as big as possible.  The wing-walls and the lintel do little structurally, and limit the under-oven storage capacity unnecessarily.  The lintel reinforcement could have been incorporated in the slab, and I would at a minimum, reduce the wall width to 12" on each side (it's 16" now) -- or eliminate them and make the base a U shape.  That would give me more room to store wood.  I also think that making the base H-shaped in plan could be interesting.  The openings of the base could point to the sides, or front and back, providing lots of wood storage space.
   
6. Finally, the floor of my storage area is too low and fills with a water that seeps in when it rains.  I plan to fix this issue by adding about 3/4" of concrete, sloped at 1/4" per foot toward the front to provide drainage.  I have since fixed this :)