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Mike D 10-30-2010 09:33 PM

Round shape
 
I am very close to starting but I have a few things to work out first. I want to close in the dome with a round brick form, kind of like Balty Knowles. I went to Pizza Bianca in Phoenix and fell in love with their round shape. I need help on how many bricks thick I need to make this enclosure (so I can build the base and slab appropriately).

-I think Balty Knowles did 2 bricks, is this necessary (can I get away with just one brick, or will this be too unstable)?

-Do I need to use cored bricks (the ones with the holes in them)?

-Do I need to use High temp mortar?

- If I use vermiculite/concrete insulation on top of the slab, will it support the weight of the bricks? I read somewhere that this type of mix is a little spongy?

-I was planning on filling in the top with extra insulation and covering it with a stucco type cap.

Any thoughts?

Mike

dmun 10-31-2010 04:48 PM

Re: Round shape
 
If these questions are about the decorative enclosure, one course of bricks is fine, as is regular type S mortar. You need extra support to support your slab, either another course of bricks, or a course of four inch blocks up to the height where you pour your slab.

Vermiculite concrete is lightweight.

I don't understand your stucco question. I thought you were planning a brick enclosure.

Mike D 10-31-2010 10:07 PM

Re: Round shape
 
Dmun, Thanks for responding (I love this forum)

Yes this is for the decorative enclosure, and the stucco would be to put on the top of the dome to seal everything in so I don’t have to build a roof. I just want to see the clean look of the brick.

What do you mean about the extra support of the slab? Do I need the extra support in the middle of the slab or on the sides and back inside the normal blocks? Wouldn’t the decorative enclosure brick be mostly or almost on top of the blocks around the edge?

I was worried that where the decorative enclosure brick joined the vent area it would get too hot, and that a different mortar would be needed. I guess I could just use a high temp in these areas, right?

I was worried that the Vermiculite concrete wouldn’t be able to support the weight of the dome and a decorative brick enclosure. Would it dent or get compress? I could just make more of an island insulating layer, as to just have it under the dome but not on under the decorative brick enclosure.

Mike

Muscats 11-01-2010 03:42 AM

Re: Round shape
 
Quote:

Originally Posted by Mike D (Post 101613)
Yes this is for the decorative enclosure, and the stucco would be to put on the top of the dome to seal everything in so I don’t have to build a roof. I just want to see the clean look of the brick.

I'm still confused, if you apply stucco to the outside, wont it hide the bricks anyway? You do not have to build a roof if you render the outside of the insulated dome. Is the round enclosure you are asking about like another dome on the outside of the insulated dome? or like a cylinder going straight up?

Quote:

Originally Posted by Mike D (Post 101613)
I was worried that the Vermiculite concrete wouldn’t be able to support the weight of the dome and a decorative brick enclosure. Would it dent or get compress? I could just make more of an island insulating layer, as to just have it under the dome but not on under the decorative brick enclosure.

are you concerned about the vermiculite concrete in the slab or on the dome not being able to bare the extra weight.

If it is the insulation on the dome and you are building another dome over the top then the second dome should end up being somewhat selfsupporting should'nt it?

Mike D 11-01-2010 08:58 AM

Re: Round shape
 
The decorative brick is in a cylinder shape (round form around the dome), as opposed to a square like most ovens. Sorry about the confusion.

I was worried about the extra weight of the decorative brick (cylinder) denting the vermiculite concrete, is this and issue? Would it be better to just put it on the slab.

Mike

azpizzanut 11-01-2010 10:51 AM

Re: Round shape
 
Hi Mike D,

You might get answers to some of your questions by downloading the free Forno Bravo Pompeii oven plans. They describe an oven building process from start to finish. There are tables that show how to size the base and hearth.

I recently made hearth insulation from perlite and portland cement. It hardened and became strong enough to support the hearth bricks and dome bricks.

Cheers,

Neil2 11-01-2010 12:39 PM

Re: Round shape
 
"- If I use vermiculite/concrete insulation on top of the slab, will it support the weight of the bricks? "

A picture or diagram would be useful, but if I understand correctly, you should cut back the vermicrete layer so that your outer brick shell rests directly on the edge of the structural slab.

You don't need the vermicrete layer over the entire slab - just under the hearth, inner brick dome and dome insulation.

dmun 11-01-2010 12:53 PM

Re: Round shape
 
Quote:

I was worried about the extra weight of the decorative brick (cylinder) denting the vermiculite concrete, is this and issue? Would it be better to just put it on the slab.
I'm thinking a sketch is in order here. I can't envision why the decorative brick wall would be on top of the vermiculite layer. That means the vermiculite would be exposed to the outside, which is never a good idea.

So let's see. Your block base is already built, the support slab poured, and the vermiculite is spread from edge to edge. Am I right so far?

Is your decorative brick not going to cover the base? That's what my assumption was. I was envisioning a single cylinder rising from the base, with the support slab cast inside the brick ring, hence my call for a support layer inside the brick ring.

As far as the cover, neither brick nor stucco is particularly waterproof. At the very least you will need a significant slant to prevent standing water on your top.

Muscats 11-01-2010 05:38 PM

Re: Round shape
 
1 Attachment(s)
I think I am getting the idea of what you are planning now.
Correct me if I am wrong, but you want to build a Pompeii oven and then build a cylindrical shaped enclosure around it. The cylinder being larger than the dome circle to allow the front of the cylinder to include the arch? So the circle of the dome and the circle of the cylinder will not have the same center? I have modified one of my sketches to illustrate, see attached.

If this is what you are going for, I would consider a slopping roof within the cylinder, you would not be able to see the roof from the outside and you can make it out of whatever roofing material you want, you would just need seal around the edge and to allow somwhere (at the back) for the water to get out.

Adding the cylinder would add weight, but no more than a square enclosure would, but you wouldn't want this weight on the insulating concrete.

One option that comes to mind would be to lay the hearth slab in normal full strength concrete lay a ring of bricks for the cylinder enclosure and then fill inside this ring with insualting concete, build the dome, build the cylinder, fill with insulation, build the roof and you are done.

dmun 11-01-2010 06:01 PM

Re: Round shape
 
I like muscat's idea of the concealed internal roof, especially since it's not likely to fill with snow in Arizona. Around here that plan would entail serious flashing, but in Arizona, a layer of roofing membrane would seal the oven. Do I envision an elaborate lipped spout with a copper downspout? Hmm.


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