Morgan, Here is a progression of the build. Hopefully the pics are in order. After the inside oven section, I added the second layer of bricks with space for the rocwool. I then stacked the bricks high enough to allow rocwool on top and then the wood frame for the roof. I had the vent custom made at a local sheet metal shop. All the bricks are firebrick because when I was building the dryfit, I didn't know how many I needed and didn't want to have a mix of bricks, this way any brick is firebrick, a little more expensive but if I modify, I don't have to worry about which brick is what. The only heat I get on the outside bricks is in the front and that is minimal (~130F right near the opening. On the sides and back it is ambient temperature. The opening changed a little so some of the initial pics were modified slightly from what you see. There is also a throat from the oven section to the opening that is 1 brick long (8.25"). The door is a box made of stainless steel that has a layer of rocwool in between. When hot and closed up, I lose about 120F every 12 hours, not the best but it could be worse.