Rookie Attempting Neapolitan Build

[jrodgers]

Hello All,

My yard currently has a decent-sized (about 61.5" wide x 28" deep x 28" high) brick structure with a crack across the top which I intend to expand upon and build into a Neapolitan-style oven. I've drawn up some plans based on things that I have read, and I'm aiming for a 36" diameter, with the dome height around 14" and the door height about 9".

In order for this to fit, I am going to extend the existing block out to a 46" depth, with the front 18" supported by 3 brick columns (between which I can store firewood). I am very new to this and am prone to getting ahead of myself on projects that I'm excited about, so I would love to avoid that on a project of this magnitude. Everything I know is based on what I've read or what I've seen, so I'm pretty uneducated.

My main questions are these, and any help is greatly appreciated:

1. How thick/how insulated do my cooking floor and support underneath need to be? From what I understand, thicker insulation will equate to longer heat retention but also longer heat-up time. This will be used primarily for pizzas, typically for relatively small parties (6-8), occasionally larger. Baking bread would be great, but I don't necessarily want something that needs to heat for 8 hours and stays hot for 2 days. I have 125 4"x9"x1.25" firebricks that I intended to double-layer on top of a 2" thick layer of fresh fire mortar/refractory cement of some kind. Would that be sufficient?

2. I plan to make the dome from 2.5 inch thick firebricks, with an insulation blanket on top, and then smoothed over with a perlite or fire mortar layer as the top layer. Does this seem logical?

I know I have many more questions but can't currently remember them. Help needed and appreciated!

[UtahBeehiver]

Have you purchase the cheap Forno Bravo eplans ($3)? It is good baseline for helping builders design their ovens. Highly suggest you purchase and read.

1. More or thicker insulation, does not take longer to heat up only helps retain the heat. Thermal mass, or thicker refractory material, ie bricks or refractory mortar is thermal mass is what takes longer to heat up.
2. Double layer fire brick splits (2.5") will be plenty of thermal mass for you needs as well as multi-day cooking.. You need to insulate under the bricks, skip the refractory mortar underneath, it just adds thermal mass, but you do need to insulate under the floor, min 2" CaSi board, or 4" of 5 to 1 perlcrete or vermiculate/portland mix.

[jrodgers]

Thank you for the advice, I'll definitely buy those instructions and look into making a perlcrete/portland mix.

I did think of another question: Will the existing block support the oven without sinking into the ground further? It isn't going to be a massive oven, but I didn't put it in myself so I'm not sure exactly how it was placed. It's clearly a bunch of bricks on top of a concrete slab but I don't know the depth. I would LOVE to use what is currently there and not have to start from scratch with it.

[UtahBeehiver]

Take pics and post. However, even a 36" oven will be a lot heavier than you think. Without knowing more about the existing slab, ie thickness, rebar, etc. It is a crap shoot on whether the existing brick structure and base as adequate.

[jrodgers]

I dug down a bit and that concrete only goes down 4 inches, not to mention the bricks look pretty beat up. I think I’ll take that down and start from scratch, might as well put in a nicer concrete patio around it while I’m at it. Will probably be back with more questions and pictures!

[Chach]

You have the opportunity to do it your way. I say go for it!