Here is my desire coming to fruition

[steffen]

I am convinced the Forno style oven will work the best for my vision.
I am in the early stages of construction, and have just poured the
concrete pad. My structure will have both an open bar-bq (Firepit) and also
a Forno style pizza oven, the concept being to transfer some of the
good wood coals to the bar-bq pit for some steaks in between pizza's.

I appreciate the time anyone takes to read through this, and hope some
light will be shed upon my project.

Thank you;

Steffen

[steffen]

As it rises out of the ground

Well I have at least paid for, and slugged the concrete block structure into my backyard. Not alot of fun, but a testament to what good things will come. 2000lbs worth of concrete block should be around for a while. I have only dry laid them to this point, just in case there are any things which need to be re-thunk before putting it all together. I have my best results, Engineering on the fly. The left side of the pit will be for the open flame cooking and Saturday night campfires. The middle section is the prep area, unto which I will put a butcher block top and some shelves underneath, and the far right side is where the pizza dome will go. I will try and rope some of the friends into a little mortar and blocking this weekend, but at least all of the hard slugging is done. I will keep all in the loop as it rises out of the ground.

Steffen

[steffen]

The Engineering of it all...

I think I will be sticking to the brick design as it is the easiest to engineer on a computer. Here are the preliminary drawings of the pit and pizza oven. Any thoughts, comments or suggestions is greatly appreciated.

Steffen

[Marcel]

Consider a 4-1/2 block square Hearth Stand

Dear Steffen,

(M) I am not far ahead of you. I have tried to read almost every entry on this forum. I have poured a 10' x 10' Foundation slab because like you, I too am considering adding some outdoor kitchen conveniences and wanted to build on the same slab.. I have pre-laid a waste line, a water line, and an electrical line. They are buried under the slab in their respective conduit materials.

(M) It was easiest for me to construct the Hearth stand of 4-1/2 blocks on each side. It involved no cutting and I figured that a square was the most economical closed "curve" for the circular foot print of the "igloo". The size is close to a 6' foot on a side square but actually, because each concrete block is only 15.5", it would be 69.5" if it were possible to stack them without *any* gaps. My Hearth Stand walls are closer to 70.5" so that's why I think of it as a nominal 6' x 6'

(M) I opted for a less interesting design than yours with the Y shaped Hearth Slab (if I correctly interpreted your drawings) and did so with some reluctance. But I read of many talented builders who were bemoaning the fact that they were using more wood than they had hoped. As a non-engineer I still realized that because heat rises that the greatest heat loss would be through the roof of the igloo dome. I knew then that I needed to build a facade that would allow me to pour in lots of perlite after I finish the igloo dome to cover it and prevent that loss.

(M) Your beautiful design seems to have less provision for insulation around and above your dome. I'm just a newbie so perhaps I'm missing something, but I suggest you look at the photos of Jim Hatch's oven. His help, along with Paulages, Robert Musa, and James Bierney, the moderator of this site, has been invaluable. I suggest you don't get wedded to any floor plan until you have at least read their many helpful suggestions. I have been at least 6 weeks in the planning stage before I even built my slab form. I'm glad I waited.

(M) If you like to write to me outside of the forum, I can send you some images of their good work as well as images of the stages I went through up till now. My email address is marceld@efn.org

(M) Good luck in any event!

(M) Ciao, Marcel

[james]

Hello Steffan,

One quick question. Are you allowing yourself enough room for insulation between the oven and the back upper wall? You should allocate 5" or so. I can't tell if your upper walls are wire/stucco, blocks, durock, stone, etc., or if there is room.

I like the grill idea. What are you going to use for the grill, stand, etc. Are you planning on using wood coals from the oven -- that would be great.

James

[steffen]

Good input, this is why I never rush a build

Thanks for the input Marcel and Moderator.

I have tried to squeeze as big a dome as possible on the concrete foundation as I could. There were many considerations in my design, if you can believe it this project started in my mind back in January as just a smoker. I am a fanatic about ribs, and this is what prompted me to begin investigating a design for a smoker.
But due to my kind heart, I dont think I could smoke up the neighbourhood with the sweet smell of ribs smoking away for hours at a time. Plus I have a Beagle who would have but one purpose in life; to break into my smoker and steal the ribs! Then the design turned into an Alan Scott Brick Vault design, then emerged into an Adobe Style Vault, and now after months of research on the internet, and pages upon pages of helpfull information, it has turned into a Forno style Authentic Dome design.
I know there needs to be a good 4-6" of insulation on the outside of the dome. I have been educated in Architecture, but havent used any drafting skills for the past 5 years, so my drawings are a quaze between what you would really see, and how i put it all together, so the drawings are not of engineering standards, but give me some key dimensions.
The finish will have an insulated blanket, then some wire mesh, then a good coating of stucco? Or is it supposed to be refractory mortar 4-6" and then an inch or less of finishing stucco for weather protection?
I will have some good photo's throughout the weekend, but coincidentally it is our annual ribfest here where I live, so the construction will have to be put on hold a few times whilst I suckle on some ribs.

Regards

Steffen

[james]

Enjoy the ribs. I think there are some postings in the forum on smoking inside a brick oven, so there is lots to look forward to.

Counting out from the outer edge of oven dome, you want 5" for insulation (loose, blanket, castable -- though 1" blanket to keep loose insulation from ever falling in, and 4" loose is a good rule of thumb and inexpensive), then your 3/4" stucco upper wall (pencil rebar (optional), chicken wire and stucco).

Enjoy the long weekend.

James

[paulages]

bear in mind that even if the dome walls butt up against what is shown as a solid wall in the drawing, there will in fact be 3.5 inches available for insulation inside the 2x framing, unless the upright walls are solid brick or whatever. in other words, the actual wall in a backerboard/stucco type finish would sit on the outside of what is shown as a wall in the blueprint.

[steffen]

The big one

Hey Paul, I like your moto

My brother in law and I have a saying which is simply "Solid" if we build it to last we both know its "Solid"

The back of the structure is 4"x8"x16" blocks, so it will be a challenge to fit in as much insulation as I can. I have seen hope's design, and this will be similar to what I will end up creating on that side of the structure.

I have a great time having so many other sets of eyes on my project.

Steffen

[steffen]

What is the smallest dome diameter recommended?

Can anyone tell me what the minimum dome diameter can be? Is there a calculation based on how big the opening can be based on the dome diameter. I am just working on the concrete block, and am worried that there may not be enough room for a big dome. Is 30" too small a dome?

Steffen

[dmun]

small ovens

Forno Bravo sells a 31.4 inch oven, the casa 80 (cm), so it can't be a completely impossible size. One US vendor, superior clay, sells an 18 inch oven, but I don't know what you would bake in it, a cupcake?

http://www.superiorclay.com/oven/articleoven.html

That said, almost everybody here who has made the Pompeii oven has made the 42 inch size. I think, for my own use, that would be too big and I have done drawings for the 36 inch. As I've written elsewhere on this forum, I'm not convinced that the dome as designed is too thick, and you could pick up a couple of inches on each side by making a half-thickness dome, like the modular ones.

I think that part of the problem with small ovens would be that with the door big enough to get anything in and out, it would be too big a hole in terms of heat loss. I know that in my work with electric kilns, the area near the door is always a "cold" spot.

Maybe James could jump in here and report the experiences that customers have had with the Casa 80.

[paulages]

if you look back far enough in the older threads, you'll find where this same question was asked (in the title of a thread), and a good answer. i believe the answer was that 30" is as small as you would want to go and still retain an adequate opening that will vent properly.

[Marcel]

Is this the quote for "the answer was that 30" is as small as you would want "

(M) Paul, is this the quote you sought?

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I am beginning the design of a Pizza Oven and BBQ grill combination. However, I do not have a lot of space.

The total floor area is around 180x120cm (180 could be extended slightly if needed).

Any advice for fitting in such a space would be gratefully recieved.

Also - does anyone have advice for sourcing fire bricks in the UK. I could just order them from a builders merchant, but I would like to build the entire thing from reclaimed materials if I can.

Thanks in advance.

James

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Here's my idea on minimum oven size. If it is possible, I would try to "fit" a 30 internal oven floor. I installed a 26.5" prefab a while ago as an experiment, and for me, it was too small. There wasn't room for the fire and food at the same time, and the ratio of oven volume to oven opening was out of kilter because the minimum oven open to fit pans and food was too big relative to the oven size. It did not hold heat very well.

Here's my math for minimum size from side to side (in inches, if that's OK).

30" Oven floor
9" Wall thickness (both sides)
8" Insulation (both sides)
1-2" Upper walls

That gives me 48"-49". What do you think?

A prefab would know 4-5" off that because the walls are thinner.

James

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Ciao,

Marcel

[paulages]

that's it.

[steffen]

Looks like I will be getting creative today

With all of that being said, my concern was the ratio of the open door to the actual cooking/heating area. I may end up pouring a bit more concrete now to support a larger footprint for the oven. Originally I had designed the oven with an angled front to it, but as I started dry fitting the angled front yesterday, I realized how amateur of a mason I am. I can only imagine that trying to fit in these strange angles with a square block will only create a weak structure which will be filled with gaps and even holes. My main concern as well is that I can build an oven with a door at least wide enough to fit a standard peel into, what is the minimum door openening 14"? Thank you as always the many sets of eyes on the project.

Steffen

p.s. pictures to follow this afternoon.