Smokehouse firebox/oven

[archeryrob]

The attached photo shows what I have and what I would like to do. The fire box would be built bigger, mainly to support the oven, even though the size it is now is plenty fine. The red shows the oven and the green the future chimney on top and smoke flow. The oven is not

The blue is where my heat bypass is now and I can use the oven as a heat bypass and likely to put a 1/4" steel plate as a damper over the entry to the oven. There is already a damper to the smokehouse. I have problems with this rusting as the roof drains right on it and I would fix this.

Now, my assumption is that I have too build an inner and outer box design for the oven and fire box. The inside of both to be built with firebrick and "Homebrew" mortar. The fire box and oven joined with a clay pipe and a clay pipe for the chimney and surrounded by brick.

Now assumption 1 - The outside brick to be separated with perlite/mortar mix but only concrete over the roof fire box dome to the oven. Assuming this hold and traps heat to the oven
Assumption 2 - Perlite insulation continues around the oven, but it not needed on the chimney.
Question 3 - Perlite mixture will not be strong enough to line the brick and substitute fire brick, correct? Nothing better than fire brick, correct?

Anything I just way off on or just skipped right past? I am real handy, but hardly qualified to be a masonry helper right now.

[wotavidone]

Just download the FB plans and build an oven.
Don't hook it up to your smoker.
Don't do funny shit with insulation.
Don't do funny shit with fireboxes
Just build an oven.

Regards,
Mick

[archeryrob]

The entire plan is to hook it up to the smoker, I do not want separate fire houses for an oven and the smoker. It can be done a guy on here built a pizza oven that have a separate smoker fire box. I need to rebuild my firebox better and wish to add an oven to it.

I did not see FB plan, but I will look.

I do know with an upward vent to the oven if that damper is open at all and the smokehouse damper shut it will always flow to the oven. I messed up with my original build with not completely lining it with fire brick. I also seemed to have learned it would work better if making it a 2" space, or more, between the fire brick and normal brick and filling with perlite mix.

I guess the question is should the space between the fire box and oven be homebrew type filled, or perlite topped with homebrew and fire bricks? Home brew would server to warm the floor of the over more, but when using it as a smoker only it would be heating the oven some when not needing too.

I am looking for experienced answers to questions, not just build a separate oven, as everyone else has. I have a different application and wish to learn to be able to build it.

[Gulf]

Like Mick, I belieive that combining the two just leads to many problems that effect the efficiency of both the cold smokehouse and the wfo.

Here is a link to Forno Bravo's Pompeii Oven Ebook Plans. I think that it would be best for you to learn how an efficient oven is designed. Your drawing depicts an oven with the flue inside the cooking chamber. That is not an efficient design.

As for as a cold smokehouse is concerned, there should never be a raging fire in the the firebox at anytime. A good practice is to burn the wood down in a separate firebox and then transfer some coals after the nasities have been burned out of the wood. You could use the oven for that separate chamber. However, I would not tie the two together.

[deejayoh]

I'd vote with Mick and Joe. If you want to connect them, I'd put them under the same roof or in the same housing - but not try to get any synergy out of the firebox. A pizza oven and a smoker are as different as chalk and cheese. They have fire in common, that's about it

[SableSprings]

Since you are not intending on changing the existing (and working) smokehouse. The oven would be simply an option to expand on what you are already producing in the smokehouse. The oven you are thinking about building is very similar in concept to a Gueulard Oven. These ovens were originally designed for bakeries in Europe and are still in use in several high end "artisan" bakeries such as Poilâne's.

For the following comments, "directions" assume you are facing the smokehouse with the smoke pipe coming out at you. Far side is against the smokehouse porch, near side would be 5' to 10' from the porch at what would be the front of the new oven. Placement of oven & firebox opening(s) - based on your smoker roof overhang, you'll probably want the firebox and oven to be accessed from one of the three sides away from the porch (you wouldn't want to be straddling your existing pipe to the smokehouse). I'd be looking building the upgrade/addition, so the firebox opens on either left or right side (even though you might get dripped upon while feeding the fire during rain ). That means with your new WFO in place, you'd be loading your loaves of bread in the oven from the near side and be able to look at the far side smokehouse over the top of the dome. I hope that made sense.

Basic reasoning is that I would not want my firebox directly under the opening to the oven (I've been burnt enough being close to hot metal, thank you) and building your oven to access it from the porch doesn't look like it would work, simply because you do not appear to have the height needed to stand in front of the oven and actually work it (and based on personal experience, you don't want sparks & cinders popping out onto your porch ).

Take a look at the two Gueulard design pics on the next post and think about what you want/need in a WFO. The advanced/multiple damper systems involved can be incorporated into your existing smokehouse but I really think this is worth continuing to flesh out and explore possibilities before doing any actual construction. Looking forward to your thoughts & comments about your intended use for this oven project.

[SableSprings]

I'm attaching two pictures (sorry, one is quite small/poor resolution) showing the basic design...one commercial size and one more Tuscan (Pompeii - high dome) size and a third photo of the flame from the firebox into the baking chamber of a commercial Gueulard. From the pictures you'll note that although possible to build, the design is fairly complex compared to the ovens on this forum.

I believe this would be a fun project, but not a simple (or inexpensive) one. I think of these ovens as gray ovens - because you could build a fire in the oven chamber (Black oven: for pizza & higher temps) or use the heat from the firebox below (white oven) to do lower temperature baking (bread, roasts, BBQ, etc.).

[archeryrob]

Thanks.

First, the roof is wood storage for the smokehouse. You are correct with there being no access on the left side of that picture.

The door to the fire box is currently on the right side of the box that you cannot see in the picture. Direct flow right to left to the smokehouse. I currently have a 3' deep and 4' wide concrete pad the fire box is setting on as seen in the pictures aspect ratio. I poured a second similar pad for feeding the fire box to the right of it. I planned on filling the first pad with FB/oven. I had figured on having the firebox door and oven door on the same right side over top of each other. You are suggesting having a door for the oven on the side facing in the picture and the fire box where it is now on the right side, correct? This would make a narrowly deep oven. Probably forcing the door on that side to be wider. You think there would be a problem having the fire box door under the oven door?

i and unfamiliar with the Gueulard Oven, and will read on it. The flame shooting out like that, looks like a blow torch fire. Seems a lot to cook by.

[archeryrob]

I'd vote with Mick and Joe. If you want to connect them, I'd put them under the same roof or in the same housing - but not try to get any synergy out of the firebox. A pizza oven and a smoker are as different as chalk and cheese. They have fire in common, that's about it

So you would say, if they are together the fire box and the over would be total separate, except for the oven being mounted on top of the fire box. A separate chimney for the fire box as a heat bypass and chimney on the right for a oven and the oven fired like a traditional pizza oven, correct?

I only have a 3' wide base down now. Does the oven have to be round? Can it be a dome rood from side to side and blocked ends? 3' seems to narrow to make a pizza oven.

Another thought, with all this separate oven discussion. The cost of all that fire brick and insulation I might as well build a separate base with cinder block and fill in the center and a concrete table. Then maybe make a clay/mud oven and cover it with a metal roof. I am not sure I am up for the costs of that many fire bricks and all. I am sure you all have minimum $750 raw costs in them ovens on the low end, correct?

[SableSprings]

I currently have a 3' deep and 4' wide concrete pad the fire box is setting on as seen in the pictures aspect ratio. I poured a second similar pad for feeding the fire box to the right of it. I planned on filling the first pad with FB/oven. I had figured on having the firebox door and oven door on the same right side over top of each other. You are suggesting having a door for the oven on the side facing in the picture and the fire box where it is now on the right side, correct? This would make a narrowly deep oven. Probably forcing the door on that side to be wider. You think there would be a problem having the fire box door under the oven door?

I was only thinking of having the firebox door on the side because it would be "safer" than having it just below where you might be working the oven. Most white/gray ovens have the firebox directly below the oven opening...I just think it does not affect the working of the oven and really would be less of a potential problem to have the ability to feed the fire from the side on this type of oven. In terms of the size of the oven, one of our members in Australia has a 21" diameter oven and has fed a lot of people with a lot of pizzas and other tasty treats. You do not have to have a dome shaped oven, it's just more structurally stable (vault - half barrel ovens need buttressing to keep them from pushing/collapsing outward). If you are looking at having a pizza/bread oven that you can use occasionally, then simply adding an insulation layer on top of your smokehouse firebox and building a separate dome or vault WFO on top is going to be your quickest and easiest solution. As you mentioned in post #9, having a firebox exhaust that bypassed your oven chamber and/or tied into the oven chimney system would be fairly easy to do (and be the least expensive option). Several of our members do hot smoke on BBQ in the oven without need of a separate firebox.

i and unfamiliar with the Gueulard Oven, and will read on it. The flame shooting out like that, looks like a blow torch fire. Seems a lot to cook by.

The Gueulard ovens are primarily used in commercial baking (bread), so the flames you see in the picture are from the firebox below during the oven heating phase. When the oven gets to temp, the bakers pull out the metal elbow piece and cover the hole with a pot of water to provide humidity in the cooking chamber and keep fire/smoke from flowing out of the firebox over the bread while baking (note that these ovens have a secondary exhaust chimney for when the access through the oven chamber is closed). Yes, the flame looks pretty ferocious in the picture...maybe having marshmallows on a stick during the firing process would be in order

As you also noted in Post #9, casting an oven would be less expensive...but the reason so many of us are always looking for "used/surplus" materials is that it can be pretty spendy to build a brick or cast WFO that's enclosed so you can use it year round ($750 new raw materials costs would be really inexpensive, IMHO).

[archeryrob]

This thread has confused me more than actually helped me. StableSprings, You've help me the most. I was figuring it would be like an offset hot smoker and refered to it as an oven. Maybe that term oven made things different in other peoples minds. I would assume even if made from Fire brick inside and I would get some radiant along with the fire, just not the same as a pizza oven would. I guess I was figuring someone here would have done something similar to what I was proposing.

So, if I build a arched fire brick roof its likely to push outward?

[UtahBeehiver]

Sorry the forum cannot help you much, we just do not see combination ovens/smokers like you want to build and the ones that have tried it do not give updates on whether their projects worked or not. But what Mike said about arch domes with vertical walls, is the vertical walls are subject to outward pressure from the dome so the wall need reinforcing (buttressing) to offset this outward pressure, just like you would see on old gothic churches in Europe. So keep us informed on how you project comes along.