Indoor pizza oven feasibility

[DanielF]

Hi, I've been researching posts here regarding pizza oven construction for a bit and before I get too far ahead of myself wondered how feasible indoor construction of a pizza oven might be.

The oven would be constructed in my new home that I'm currently in the process of building. The house is framed and closed in and in the anticipation of either a masonry heater or kitchen hearth I expanded the slab on grade from 7" to 12" where the heater or hearth would be located. All is reinforced with rebar and steel mesh. My floor plan is open so the 14' wide kitchen is open to the main living space.

Thanks, Daniel

[deejayoh]

Welcome Daniel

I've always thought an indoor pizza oven would be great. And I think it is feasible, but you do need to realize that smoke leaking out of the front of the oven on start-up is pretty much a given. It will come out the mouth until the flue heats up. So you have to plan for some ventilation for that. The other big gotcha I can see is storing wood, and just having firewood in the kitchen. It's not the neatest thing in the world. But if you have a good plan, I'm sure those things can be addressed. Another thing you might think about is a gas oven, or at least having gas as an option. No smoke, no firewood.

I think there is at least one build on the forum that has two openings, one inside and the other outside. Can't remember whose it was or what the outcome was - but seems like a good approach if you could make it work. Light from the outside, and cook from the inside.

[Gulf]

Hi Daniel,

Deejayoh has given you some great advice and some things that you need to consider about an indoor oven. I'm going to throw a couple of more things out there for you to consider. First of all is home owners insurance and the local fire codes. If you haven't, research it fully. You don't want to build something that you can't use.

As Dennis mentioned, ventilation is absolutely necessary. An air intake, inside the entry of the oven or simply slightly opening a kitchen window while firing the oven may be all that you need to do. The idea is to replace the exaust air (that which is going up the chimney) as needed. Most residential homes are fairly air tight. So, that is a consideration.

Draft is another. Draft is what pulls the exhaust smoke up and out of the chimeny. Draft is created by a heated column of air. Preheating the flue before lighting the kindling in the oven will greatly help keep any smoke from entering the room from the oven on startup

When I was young, one of the add ons that folks liked for a fireplace was a wood storage. When room for one was allowed, it was an a tunnel from the outside to the inside for a nights loading of wood. We built them of all masonry to the side of the fireplace. They were the depth of the fireplace with a door to the inside and outside. The storage was loaded from the outside through the exterior door. . Makeup wood for the fireplace was retrieved from the inside door. I can see the wood storage area under a WFO with an access to the outside and inside with much more stroage. Maybe even a cart to make it easier to stock.

[DanielF]

The fundamentals of draft and function of the chimney and archway opening on a pizza oven is my primary concern regarding an indoor oven. I'm a stone mason by trade and have worked on a couple fireplace builds, the designs of which are critical to proper draft. I'm wondering if the opening of a pizza oven functions in the same manner. Deejayoh referred to smoke spillage on startup which would be unacceptable in the house, but is this commonplace on a properly designed oven? (I'm providing dual sources for outside air for both my woodstove and pizza oven). In a fireplace the relationships of the opening dimensions to the firebox dimensions to the smokechamber height and id of flue (also height) are critiical to adequate draft. Similarly, are there dimensional rules/relationships for adequate draft on a pizza oven?
As far as local codes, the clearance to combustibles, chimney type, and structural concerns are similar to a fireplace or masonry heater. I'm good to go in that respect.

Thanks, Daniel

[Gulf]

The formula for the opening of the oven to the flue size is not used as we use for fireplaces. There have been some solid performing recommendations for oven size to flue size. Oven size being the diameter of the ovens foot print. Also, I'm referiring only to the Pompeii design. I believe that a 5" flue is recommended for up to a 32" oven. A 6" for up to a 36" oven and an 8" for up to a 42" oven. I will invite any corrections or recommendations to those. My oven is a 44" and I have an 8" square all masonry flue

I don't believe that smoke spillage into the room for an oven should be no more of a proroblem than it would be for a wood burning fireplace. There are many wood burning fireplaces that are not in use today because the owners do not know how to start a fire imo. As I mentioned above, preheating the flue is one of the key things to always do before lighting the fire a fireplace or in an oven. There are some other key points that I want to bring out after a nights rest. I go to bed when the chickens do .

[david s]

For a Pompeii style oven, that is an oven with a flue at the front, it is a cross draft system which requires good smoke flow when the oven is cold and the cool flue is not creating a draft. In fact if you visit Pompeii the large oven at the bakery has such a cross draft flue, but in operation was probably never cold, being fired every day. Taking a decent look around there are many smaller ovens in private homes there where the ovens were much smaller and had updraft systems. That is, a flue rising from the apex of the dome in much the same way as ancient Roman kilns. Having built one of these kilns, I also built my first oven using the same system. One big advantage is that it draws beautifully from cold and presumably was the preferred option in Ancient Rome for private homes. Very annoying to fill your room with smoke. A second advantage is that there is no deep tunnel to have to work past creating much better access. The down side is that the heat jumps straight to the flue so there is a higher fuel consumption.

These pics show an old oven in Penzano, Italy that utilises a fireplace to draw away the smoke. Most kitchens in old castles use the same system.

Penzano Chinonceaux
Pompeii

[DanielF]

For a Pompeii style oven, that is an oven with a flue at the front, it is a cross draft system which requires good smoke flow when the oven is cold and the cool flue is not creating a draft. In fact if you visit Pompeii the large oven at the bakery has such a cross draft flue, but in operation was probably never cold, being fired every day. Taking a decent look around there are many smaller ovens in private homes there where the ovens were much smaller and had updraft systems. That is, a flue rising from the apex of the dome in much the same way as ancient Roman kilns. Having built one of these kilns, I also built my first oven using the same system. One big advantage is that it draws beautifully from cold and presumably was the preferred option in Ancient Rome for private homes. Very annoying to fill your room with smoke. A second advantage is that there is no deep tunnel to have to work past creating much better access. The down side is that the heat jumps straight to the flue so there is a higher fuel consumption.

These pics show an old oven in Penzano, Italy that utilises a fireplace to draw away the smoke. Most kitchens in old castles use the same system.

Thanks for the info. Helps a great deal.

I've noticed in some of your replies that you've built and use smaller diameter ovens. I currently make pizza at least once a week for my family of 4, and I make bread 2-3 times weekly. When I make pizzas I'm cooking 3-4 16" pies which is an ample amount for my family for dinner and next day lunches. Bread is 5 one pound loaves. This is in my gas range, of course.

I'm wondering what is a good balance of size of pizza oven that would enable me to cook the amounts I have been cooking without being oversized. In other words, I'd prefer the smallest size oven that would fit the needs described but not so small that fitting a small fire and pizza on the cooking hearth would be difficult (your experience/suggestion of size of pizzas in relation to diameter of oven would be greatly appreciated and the most important aspect of what I'm trying to understand)
Thanks very much, Daniel

[david s]

I build small (21”) cast ovens primarily to cut down manufacturing costs. But operation is largely down to management. My mobile version is used for demonstration and hire. I regularly cater for parties of between 30-50 guests and in a 2 hr period can crank out around 50 pizzas, prepping cooking and cutting all the pizzas on my own. If everyone shares whatever comes out of the oven then satisfaction is guaranteed. Individual pizzas per person would not work.

A small oven oven is far more economical with fuel. If you have a large one you won’t be firing it up on a Fri night for 3 pizzas for the family, but you can easily if your oven is small. Likewise if you want to cook bread 3 times a week.
There are times when I wished my oven were bigger, but many more that I’m happy it’s small. From the kind of cooking you intend, I’d suggest around 30” would suit you, but certainly nothing bigger than 36.

[Gulf]

Continued from above.

Sorry about getting back to this so late. One of the other key things is a good smoke collection chamber to transition from the entry to the flue. It should be a gradual transition. The cross view would look like an upside down funnel.

[DanielF]

The formula for the opening of the oven to the flue size is not used as we use for fireplaces. There have been some solid performing recommendations for oven size to flue size. Oven size being the diameter of the ovens foot print. Also, I'm referiring only to the Pompeii design. I believe that a 5" flue is recommended for up to a 32" oven. A 6" for up to a 36" oven and an 8" for up to a 42" oven. I will invite any corrections or recommendations to those. My oven is a 44" and I have an 8" square all masonry flue

I don't believe that smoke spillage into the room for an oven should be no more of a proroblem than it would be for a wood burning fireplace. There are many wood burning fireplaces that are not in use today because the owners do not know how to start a fire imo. As I mentioned above, preheating the flue is one of the key things to always do before lighting the fire a fireplace or in an oven. There are some other key points that I want to bring out after a nights rest. I go to bed when the chickens do .

Just to clarify, when you say oven size being the diameter of the oven's footprint (in relation to dtermining flue size) are you referring to the inside diameter of the oven?

[DanielF]

Continued from above.

Sorry about getting back to this so late. One of the other key things is a good smoke collection chamber to transition from the entry to the flue. It should be a gradual transition. The cross view would look like an upside down funnel.

Other than this there are no other rules that would affect draft, i.e. the width or depth of the vent landing? Also, regarding the relationship between the outer vent landing arch and the oven opening itself - are there any rules for this relationship? Does the vent landing outer arch and oven opening need to be of equal height, or does the vent landing outer arch need to be lower in height?
To clarify, if it makes any difference, I'll be casting this oven.

Thanks, Daniel

[Gulf]

The "vent landing arch" opening needs to be larger than the inner arch to allow the easy placement and removal of an insulated door. I think that an oven's vent landing should be at least deep enough to fit the flue's diameter. Casting the vent will give you a little advantage over us that build with brick. Just design a smoke gathering chamber like I mentioned above. Some, just put a hole in the top of the vent arch form for the flue. That may be okay for an outside oven but, I wouldn't want to chance it with an inside oven.

[Alomran]

[QUOTE=david s;n419688]

These pics show an old oven in Penzano, Italy that utilises a fireplace to draw away the smoke. Most kitchens in old castles use the same system.




Look at the amazing length for the pizza peel on the right hand side, it must be at least 3 meters long! the oven must be gigantic!
I was in Penzano only 4 months ago.

[Alomran]

Would you advise to have a marble platform or a landing plate outside the oven door to use for p[lacing food there?
If the oven is approx 2m in diameter, adding the smoke chamber which could be around 46cm, won't that be adding more distance between the user and the centre of the oven. Also, The length of pizza peel stick is going to be a problem!

[david s]

[QUOTE=Alomran;n419991]

These pics show an old oven in Penzano, Italy that utilises a fireplace to draw away the smoke. Most kitchens in old castles use the same system.




Look at the amazing length for the pizza peel on the right hand side, it must be at least 3 meters long! the oven must be gigantic!
I was in Penzano only 4 months ago.

My apologies, I did not label the pics in that post, and that may have caused you confusion. I have now done so.That particular pic was not the one in Penzano, I think it was in Chenonceaux, Loire river France. Although the peel on the right is very long, the oven was not. I suspect someone mistook it for an oven peel but it was more likely a barge pole/rudder used when transporting goods on the river as Chenonceaux straddles the river.