137cm external dome diameter

[Lucag]

Hello everyone!




I have made a circolar concrete slab of 137cm diameter to support dome + entrance. This is the maximum space I can work with including dome insulation, rendering, etc.




I have calculated 86cm internal diameter for the oven.




86cm internal diameter

+

11cm brick thicknesses (each side)

+

10cm ceramic blanket (each side )

Held together by chickenwire

+

4cm external finish (each side)




Total oven diameter:

86cm+ 22 + 20 + 8 = 136cm







My questions:

———




1) does it work for you?




2) Will the entrance & cimney fit in this space? I see many builders adding the entrance way outside the dome perimeter... but I am not sure I have space for this.




3) what could be an ideal size for the door of an 86cm dome ( width /height )

[david s]

1. I think you will have to make your oven with a smaller internal diameter.
2. I am a fan of a really shallow entry that starts well inside the perimeter of the base of the oven. This allows far better access to the oven making it easier to use. Unfortunately it is quite difficult to make the entry shallow if you build it in brick because you are limited to the thickness of the brick units. A cast flue gallery would enable you to make it both shallower and thinner.Mine is only 5” deep with a separate 2.5” cast decorative arch sitting outside it.
3. The height of the oven door mouth should be approximately 1:1.6 of the internal dome height and the outer mouth at least another inch higher and wider so you have room for door fitment. The width of the door is up to you. The wider it is the better the access but gives you greater heat loss. Mine is 17.5” and I find it works well.

[Lucag]

Thanks for your answer!!
I did not get why it should be a smaller internal diameter, it’s because of the space I will need for the entrance?

I don’t mind a 70cm oven if it’s the only way... it still seems pretty big for me... I’ll cook one pizza at a time anyways.

[david s]

Yes, it’s because of the extra area required for the entry. Check your floor plan and measurements carefully before beginning. Most folk cook only one pizza at a time mostly. After all it takes less time to cook one than it takes to prepare one. At home we just share whatever comes out of the oven. A smaller oven consumes less fuel, consumption being roughly proportional to the chamber volume. This means a small increase in floor area increases the chamber volume enormously. Using less fuel also means that you will use the oven more frequently. Eg you don’t think twice about firing the oven to cook three pizzas or a small roast. You just can’t cook a whole pig or bake bread for the village.

[deejayoh]

Another thought on this. Since you don't need to insulate under the entry area, you could pour an additional concrete slab that is cantilevered over the front of the oven for your entryway. That slab could be ~2 inches - same as your insulation - and then build the entry on top of that.

The challenge would be tying the new slab into the base in a way that was strong enough to hold the weight of the entry arch. It would have been best to tie in the rebar before you poured the initial slab.

[Lucag]

I would like to keep it inside the base, I think it will look better.
i am stuck with the calculation of my ideal internal diameter.

What is the best way to calculate the ideal internal diameter of my oven based on my available space?
( 137cm diameter for the floor, which would include the entrance)

Let’s say I try to use 80cm internal diameter and I start at the very end of my base. This gives me 57cm for the entrance starting from the internal diameter.

are they enough? Where I am supposed to position the first arc and the second arc and what door size do you suggest for 80cm diameter ?

[david s]

You can push the entry well inside the internal perimeter of the oven to gain extra space. Do an accurate scale drawing.

[JRPizza]

Lucag, for talking purposes I attached is a sketch of an oven with a standard 1.5 brick entry sitting on a round base. You can see that the oven has to be shifted back on the slab to accommodate the entry which reduces the overall size. You can go with a shorter entry, especially if you cast one like David likes to do and this will allow you to have a larger interior. You can also do as Deejayoh suggested and make a cantilever entry. A friend of mine did this and as you can see in the second picture his oven looks pretty good with the periphery of the oven all the way out to the edge of his round hearth.
I am a big fan of using a cad program to sketch out different options, but you can do it like my friend Gulf on a large piece of cardboard and move it around on your hearth, but using cad lets you make changes on the fly.
I chose to use the door height and width relationships to oven ID given in the FB oven plans as a guide and scaled them for my oven size, as changing the width and position of the opening will change how much cooking area you have and how fast the oven loses heat so I wanted to go with proven designs. You might want to see if David will share some dimensions with you so you can see what you might be able to squeeze into your existing space. If I have time I might be able to get an idea of how big of a conventional design you could fit in, but I highly recommend trying a cad program so you can use it throughout your build as a guide. If you want to give it a try I use a free program called Freecad. If you do a forum search for that term you can find a few threads where I walked some builders through the process.

[Lucag]

Great suggestion. I have used adobe illustrator to draft a simple plan. What do you guys think? It seems to me that I can easily fit 80cm internal dome diameter in my 137cm concrete slab.

what am I missing ?

[Lucag]

Sorry img upload did not work... I will try uploading a screenshot from my mobile

[Lucag]

Nevermind... mobile upload does not work and I cannot edit the previous post. You can find my oven plans here:
https://www.dropbox.com/sh/579fgct23...uqgm5c7ka?dl=0

[david s]

I can't attach things to PM's, but this attachment shows what i meant about doing an accurate scale drawing of the side elevation and also the door rebate.

[JRPizza]

Lucag, here is how I set the distance from my inner arch to the center of the oven, similar to what David is showing above. This ensures that a full length brick at the top of your arch (top dead center) will mate with your dome without having to go out of round. To set the arch you will need to know how tall you want to make the opening - I'm guessing around 26cm?

[Lucag]

Thank you everyone. Profile plan is coming. JRpizza a clarification on your plan, sorry if they are stupid questions.


1) All the space under the brick in the profile view will not contain your dome correct? If I understood well the drawing It will contains more bricks of the arch, like in the image in attachment.

2) in your design what is that small square near the brick?

[JRPizza]

Think of that picture as what you would get if you split your oven in half looking straight down the opening, then removed one half and looked at it from the side. The brick in my picture is the top dead center brick sitting by itself. So that said, underneath the brick I have shown is the oven opening. There will be bricks like you have drawn to the left and right of the top dead center brick. The small square in the picture is where I took some measurements in my cad program - I sort of forgot they were there.