There’s a lot written about building a wood-fired brick oven, but possibly the most psychologically difficult barrier to beginning once you’ve built a base – for most of us who haven’t laid a brick before – is the assembly of the 3-dimensional arch which is the dome.
Once you’ve sketched it out, you probably realise the second biggest challenge will be working out how the opening arch (through which the food will pass) meets the dome, and finally – if you do include a chimney in your design, how on Earth you build that on top of your structure without weakening the dome or opening arch – given that there is going to have to be a hole for the smoke to pass through. The number of collapsed chimney arches I discovered in my online research reminded me that enthusiasm and drive will not overcome physics.
If you were building a wall, you’d use a spirit level, but if you are building a hemispheric dome (bread oven), or flattened hemisphere (pizza oven, Naples-style), you need something else to help guide how far each brick must lean inward, in successive layers of brick.
Part of the solution will be creating a dome gauge, which I’ve never seen for sale commercially. I looked at a lot of online forums, and came up with my own design utilizing things I could get from hardware and DIY stores. In particular 6mm screw thread rod was integral to the design, inserted through a rotating trolley wheel in which I’d drilled a 7mm hole – secured with wood resin. The dome gauge is held in place in a wooden frame on your brick hearth, the frame being a rigid straight-edged figure of 8 affair, jammed inside the first brick layer.
I used a handful of 6mm steel components, and these have definite names in the trade, the rod being “Steel M6 Threaded Rod” (£2.18 per metre from B&Q), I used two M6 Threaded bars, and a variety of M6 bolts, nuts and washers. It may be worth considering using a serrated flange nut, because the frequent manipulation of the dome guage can cause your nuts to loosen. The right-angle is called an “angle bracket” or corner brace, and this is what will make contact with your half-bricks in your build. If you are building for a potentially commercial operation baking bread, or community bakery, you might want to build using full bricks, but this is not necessary at all for domestic baking or pizza.
You can also see this dome gauge in use in the photograph below as I added the third layer of dome bricks. Note: the hearth is protected from the fire mortar with plywood, and no holes have been drilled in the hearth bricks.