Here's a mostly photographic account of the building process

Foundation

This is a corner oven and the foundation is made in stone, with two openings for easy access to the wood storage underneath, with a capacity of about 1.5 cubic meter.
My neighbour, who is a professional stone mason, built the foundation -a good learning experience by observing how he was operating which helped me later on in the project.

In the beginning there was nothing

Lower stone wall started.

Base almost finished. The stone lintels are recuperation of old doors frames. You can see the hinges.
I'll be able to store about 1.5 m³ of wood.

Steel rebar frames to pour the oven hearth.
The orange pipe is for electricity in case I want to integrate a light on the oven opening.

Oven hearth done

Hearth insulation

As I mentioned earlier, insulation is of primordial importance if you want to heat your oven instead of your neighborhood. Good insulation means less wood to reach a given temperature and better heat retention, which means more bread and pizza for the same quantity of wood.

Perlcrete insulation

I used a mix of perlite and Portland cement + heat resistant fibers for the hearth insulation.
I divided the earth insulation layer in two parts: one for the core, just under the cooking floor and one for the part supporting the dome wall. Since the two areas have to sustain very different pressures, I wanted to use the highest perlite mix ratio possible for each area.

internal part under the cooking floor: I used a mix of 8-9 parts perlite for 1 Portland
For the bricks I used, I found that the floor bricks would correspond to a pressure of about 0.011 kg/cm² so I could use a much higher percentage of perlite.
the part just under the dome wall is subjected to a much higher pressure since it has to support the whole dome mass.
A minimal estimate can be calculated as follow:

P = total dome bricks weight/supporting area.

The supporting area corresponds to the floor surface comprised between the internal and external walls
A = ϕ/2(R_e² - R_i²)
with
Ri₌internal radius
R_{e =}external radius
ϕ = total dome angle less door aperture (5Π/3 rad = 300 deg in my case)

In my estimation, the dome would use about 155 bricks, of 2.7 kg each, so the resulting pressure would be:
Dome mass: 155*2.7 = 418.5 kg
Supporting surface: Ri = 46 cm, Re = 46 + 11 = 57 cm
=> A = 5Π/3/2*(57² - 46²) =~ 2966 cm²
Which yields a pressure of P = 418.5/2966 =~ 0.141 kg/cm^{2
This is without counting the joints mortar, the refractory mortar coating on top of the dome, the dome insulation and the mortar water (which will evaporate after curing)
This is more than 10 times what the cooking floor supports, but well under the compressive strength specifications you can find for perlite concrete mixes.
Based on this and other readings, I set the mixing ratio to 1/4 for that part of the hearth insulation, mixed with fibers for added strength.}

Perlcrete mixing

I prepared the perlcrete by first mixing the dry ingredients Portland, perlite and reinforcing fibers. Once I got a homogeneous mix, I added water. I used about 1.5 parts water for 1 part cement. For the higher perlite ratio (used for the dome) I used a little more water as the mix wouldn't hold together. The mix shouldn't be runny.

Perlite is quite brittle and needs to be mixed gently as it would breakdown otherwise if you were to use a cement mixer or even a hand mixer.
I mixed everything in a wheelbarrow which was really easy since density of the mix is very low thus not requiring any power tool. I used a hoe/a large piece of plywood to do the mixing. Everything was done with a few wheelbarrows.

Perlite I used, ~ 5mm granularity, 90kg/m3 density

Perlite, Portland cement and fibers

Mixing the perlcrete. The mix has a dry consistency. I used about 1.5 - 2 volumes of water for 1 cement

Core hearth insulation

Filling the core hearth insulation

15 cm of 1:8 perlcrete

Cake is ready!

Outer hearth insulation

Outer hearth insulation ring: 1:4 perlcrete

Outer hearth insulation ring finished

Dome construction

The dome construction is where things start to be funny and take a totally unexpected turn.

Painful attempt to dry fit the dome

My initial idea was to do a dry fit, index the bricks by layers and then reassemble everything 'on site'.

My motivation was that while I was doing the dry fit (not on site), the earth slab and hearth insulation would have all the time to cure and then dry, while if I was building the dome directly on top, there would be liters of captive water underneath which would take ages to dry.

I quickly found that it wouldn't work as I overlooked some important points.

In my initial plans, I wanted to taper the bricks on all four sides so that I would get a 'perfect' dome. I thought this would require less mortar and would be structurally stronger. The first layers would be half bricks and I would use thirds in the last layers.
The problem is that I quickly realised that the wet saw I had (which someone graciously lent me) didn't have enough room to cut the bricks along their wider side. I ended up tapering only along the dome meridians and had to cut brick wedges to compensate for the spaces between layers. In these conditions, doing a dry fit cannot really work as the bricks tend to slide and things start to collapse starting from the third layer. If the bricks had been tapered on four sides without using wedges, I believe that it would have worked. Added to that the fact that there's a whole world of difference between idealised tapered bricks and real life (eg: diamond blade thickness, cuts inaccuracies, brick uneven dimensions, sloppy work, etc.), which means that I wouldn't be able to assemble the 'perfect dome' I had in mind. You can see examples of domes using tapered bricks, done by a professional oven brick builder here and also here

So I forgot about the dry fit and started to build it directly on site. A good example of non feasible theoretical planning!

Dry fit? did you say dry fit?

Building the dome

Some cabalistic drawings...

First layer of many

Using expanded polystyrene forms

Drawing an ellipse for the inner arch

Inner arch

Inner arch, similar to the Arc de Triomphe in Paris, but less famous

Refractory mortar

Regular mortar cannot be used for laying refractory bricks because it cannot stand the high oven temperatures (up to 500 degrees) and will start to break down. One solution is to buy premade refractory mortar or make your own refractory mortar using fireclay, hydrated lime, Portland cement and sand. I decided to go for that solution since I couldn't find real refractory mortar around here. There are various recipes for the mix. A common one is 3 parts sand, 1part fireclay, 1part hydrated lime, 1part Portland cement. Since I used a wet saw with a collector tank, I got plenty of fireclay at my disposal which allowed be to make enough refractory mortar for the whole project.

Cutting with a wet saw. This is really handy as the fireclay dust accumulates underneath in a collector tank.
I use it for making refractory mortar

Fireclay from the brick cuts. I collected it to make refractory mortar

Dried fireclay. I made refractory mortar using 3x sand, 1x fireclay, 1x hydrated lime, 1x Portland cement

some more layers

Finishing mortar joints. Working on a corner oven is not practical at all.

Soon will be finished

Nearly finished

Two more layers...

The end of the tunnel

Yup, that's for the keystone

Dome finished. Not that perfect!

Dome insulation

The dome insulation is done using 1:8-9 perlite Portland mix. Since It doesn't have to sustain much load I could go for higher proportions of perlite, thus providing higher insulation capability.

10 cm of 1:8 perlcrete dome insulation

10 cm 1:8 perlcrete dome insulation

Thermal breaks

One area where most of the heat escapes is through the door and door arch. Typically the interior arch supporting the dome is connected to the oven entry arch and is a cause of heat loss. By allowing gaps or 'thermal breaks' between these elements, it's possible to break the continuity between the interior and the exterior and thus to mitigate the heat losses.

Thermal break between the first and second arch

Thermal break at the chimney level

Thermal break between the first and second arch.

Oven curing

Once the oven dome is finished, it's not that you can start right away with a Chernobyl like kind of fire. No, instead you first need to keep the oven moist so that the concrete can cure. This process enables the cement to harden properly and achieve better resistance to stress.
Only after that you can slowly bring the oven up to speed with a series of gradually intense fires over a period of a few days to a week.
The gradual fires will help to slowly get the remaining water out of the masonry. If you start a big fire right away, this water will boil and will cause cracks in the bricks (which were soaked in water) and mortar which will damage the oven structure.

In my case, I kept the oven under a plastic sheet for about a week for the cement curing and I did a fire curing spreading over a week. The fires were done mostly using small branches and the flames usually never touched the dome ceiling. During this process, I moved the fire on the cooking floor to dry uniformly. I didn't have a thermometer at that time so I couldn't really measure the temperature.

One of the curing fires

Stone work

I've never done any stone work. Needless to say that it's a painstaking work which requires a lot of skill and patience. That's an art. There's some magic happening with the hammer and chisel. A wrong angle and you hardly make a dent in the stone. The chisel too tilted, and you break the stone. There's that fine balance between the chisel angle of attack, the force with which you hit with the hammer and other mysterious factors that I could only slightly grasp during this project.
More than once I had the frustrating experience of cutting a stone to an almost decent shape only to see it break in two after I would tell myself 'okay, a last cut here to make it perfect'.
How many times did I hit my hand instead of the chisel? That's another story.

Painstakingly cutting each stone...
How many times did I hit my hand instead of the chisel?

I have literally tons of stones of various sizes

Stone arch

Using a form to build the arch

Not too bad

Stone walls

I sometimes get unexpected visits from an inspector
to check on the work progress

Last brick layer before the roof

Last layer done, joints cleaned. Next will be the filling with loose perlite and light expanded clay
for extra insulation and placing the flat roof + chimney

Loose perlite/expanded clay insulation

The stone enclosure is now done and can be filled with leftover perlite I had. I used it also to fill the gaps in the rockwool panel I used. I also had a few leftover bags of light expanded clay aggregate (leca) which were used for insulating the house floor.

Loose perlite used to fill the gaps in the rockwool panels.

Loose light expanded clay aggregate

The enclosure is now filled with loose insulation. Next will be the flat roof

Roof and chimney

This is now the final stage of the construction with placing the roof.
I decided to have a flat roof, slightly slanted so that water can runoff. The roof is made in concrete.
Kiko, my neighbour who is a professional majstor (in Croatian) did most of the job for this part. I was the apprentice!

Supporting cement boards

In order to pour the cement roof, I first made 3cm thick cement boards. They are just used to retain the roof wet concrete which will be poured on top of it.
To make them, I created rectangular forms (3x 80cmx50cm and 1x 140cmx60cm) in which I poured fiber reinforced concrete. Unfortunately I erased photos of the boards.