2024 Neapolitan oven build

[daidensacha]

Hi All,

I’m Daiden. I’m new to this forum, but after discovering the Forno Bravo plans online many years ago, it has long been on my bucket list to build my own oven. I’ve built it many times over in my head, and in Sketch-up, refining and changing the specs, working out details so I can be clear when the day comes.

I’ve decided 2024 is the time, and now waiting for the ground to thaw so I can get started with the foundation. I’m building a 40” (1020mm) Neapolitan style oven, with dome height of 426mm. I’ve got my list of materials pretty much sorted, but still not 100% certain on the final order could use some input and would really appreciate any feedback from those with experience and knowledge.

My love of pizza goes back to 1984 when I got my first job working as a pizza cook for 2 years at Mateos Pizza in the hills of Kalamunda, Perth, Western Australia. That experience stood me in good stead and I often make pizza at home, using an overnight biga ferment.

Looking forward to posting as the build commences.

[daidensacha]

I’ve been working through details, making changes and refining my plans in sketchup where necessary.

It’s a new vocabulary, with new words and more importantly meanings to be grasped.

Thanks for very clear input in my post Optimum Base insulation and Floor thickness for retaining heat from david s about floor and dome insulation, thickness of floor bricks and the dome wall, and heating the thermal mass.

Oven Style.
The oven will be a Neapolitan style oven, with inside diameter of 1020mm with internal dome height of 525mm. At 425mm inner dome height, I’ve designed it slightly higher than the recommended 406mm height. I want to cook Neapolitan style pizza, and to use the ovens retained heat to cook in the days following pizza cook. To this end, I will cover the dome 75mm-100mm of fire blanket insulation, then 150mm of vermiculite/perlite mix insulation, covered at last with a layer of waterproof mortar.

Hearth and floor and insulation.
Hearth itself will be 150mm slab reinforced with rebar. The rebar will also support a landing at the front of the oven. Insulation will be 100mm ceramic fibre board, with 64mm thick firebrick floor. I was planning to use 75mm ceramic fibre board, but it was only 30 Euro more for 100mm, so it seemed worth the extra.

I’m aiming for an oven floor height of 1150mm, which will put the top of the opening at 1430mm. At 172cm, it should give me a clear view inside the oven, and is a comfortable height for me to work with.

Arch and entrance.
The inner opening will be 500mm wide with height of 280mm. The outer arch will be 24mm greater than the inner arch for sealing with an insulated oven door. The arch will be built with fire bricks as I am getting a pallet (238 bricks), which cost less than buying 200. I can use the left overs as I want to also build an open fire grill beside the oven.

Chimney.
On the oven arch I will cast a level platform for the chimney out of refractory cement. On that will be a refractory chimney, insulated with 25mm of fire blanket in a gap between the chimney and the brick. THe oven will be under cover, so a flu will then go through the roof.

Image of the plan is included below, pretty much the final draft for now.

[daidensacha]

Insulation

Very useful info in a thread Vermiculite only insulation? about Vermiculite insulation by “david s”.

Before the advent of Ceramic Fibre Blanket that is exonerated as a Class 2 carcinogen, I used to do two 35mm layers of vermicrete with a week of drying between layers ( a thicker layer does not allow moisture deeper in to dry fast enough).
Now, because the newer generation of exonerated blanket has come down closer to the older non-exonerated stuff I use blanket topped off with a layer of 10:1 vermicrete which has around the same insulation value as blanket for the equivalent thickness.I find 10:1 is about as lean as is comfortable to go without it being too crumbly.
A mix of perlite and vermiculite also seems to work better than either of them alone. A handful of powdered clay for every litre of GP cement imparts more stickiness to help application.

For this interested here's my 10:1 recipe:
By volume;
5 parts medium grade perlite
5 parts fine grade vermiculite
1 part GP cement (+ a little powdered clay)
4 parts water

Mix dry ingredients then add water slowly folding in as you go (best done in a barrow)
If water pools in the bottom add a little more dry material. Too much water will wash the cement off the grains of perlite and vermiculite.

Size grading is different in Germany, and EU.

In Germany I haven’t found Perlite or Vermiculite graded as fine or medium, but usually in a range of millimetres.

Vermiculite
In google I found fine grade vermiculite defined as 0-3mm in size. Closest I found which I have bought is 1-3mm.

Perlite
I didn’t find any definitions for medium, so assuming it’s similar to the grading sizes of Vermiculite, I decided on 2-8mm perlite.

I’ll follow the recipe as above for the vermiculite insulation over the fire blanket on the dome.