Introduction: Brick Oven

Picture of Brick Oven

For this Instructable, I have decided to go through a project that I completed a couple of years ago. I designed and built a brick oven in my back yard through a lot of hard work and several visits to the chiropractor. Most of the brick oven was hand built and this was due to two main reasons. First, my backyard has two levels which prohibit the use of any excavation equipment. The second reason is that I am not made of money. More time than money means that a lot of the things I want need to be handmade or modified. I also like to build stuff so it is not all bad.

If you are wondering where I got my plans to build the brick oven go to fornobravo.com. They have great kits for residential and commercial brick ovens. They also have free plans for you to build your own oven and a great community of brick oven enthusiasts that are more then willing to help you with issues.

After spending about 3 months on the site and deciding what I wanted to build and designing the oven, I faced the hardest part of the build, convincing the wife. This involved showing her that my brick laying skills did not totally suck by building a small brick wall between my upper and lower yard. As you can see, it worked. Your results may very...

Step 1: Building Permits and Foundation

Picture of Building Permits and Foundation

First thing you need when doing a project like this is a building permit. This is important! Without a building permit, the city can ask you nicely to dismantle your oven and start over. In my case, when getting the building permit, the city had never issued a permit for a brick oven. They had just issued a permit for an outdoor fireplace. Close enough of a match that I the same requirements when building my oven, yay.

Here are pictures of my foundation. I am built an oven that has a base measuring 5 feet by 6 feet. Because I live in a fairly northern area, Northern Illinois, I needed a hefty foundation. I hand dug a foundation that is 1 foot deep into the top soil and an additional 3 feet into the clay. Each of the trenches is a foot wide. Additionally, there is an 8 inch deep, rebar reinforced slab that will hold the oven. Lots of work and at least one visit to the chiropractor.

Step 2: Pouring the Slab

Picture of Pouring the Slab

After pouring the slab and getting an inspection (building permit remember?), it was time to pour the slab. Based on my calculations, I had to hand mix almost 3 cubic yards of cement. Nope, time to call a cement truck. Three cubic yards, while a lot to me, is a really small order to a cement company. Then there was the issue of my two layer yard. I decided to build a ramp to dump the cement into the foundation. This actually worked really well. It took 23 trips with a wheelbarrow to move the cement from the street to the back yard. Oh yeah one more thing about cement trucks, they charge you for every five minutes over 20 minutes for delivery. This added an extra $20-40 dollars for delivery and gave me a work out but it was better then mixing by hand.

Once you have poured your foundation, smooth off the top and let it sit for a week. This will allow time for the cement to cure and you to recover. You can then remove the forms and move to the next step.

Step 3: Supporting Walls/base

Picture of Supporting Walls/base

For this step, I build the base of the oven. This involved approximately 90 cinderblocks arranged in a "U" shape. The center section will stored the firewood and keep it dry. The number of courses needed will be determined by your finished height. In my case, I had to bring up the level to my deck and then add about 30 inches. A good set of plans will make these decisions much easier. Anyway, I dry stacked the cinder blocks. Made sure that they were at the height I wanted and then used "Quikwall" by Quikcrete instead of mortar. This is cement with fiberglass fibers used to tied all the the cinder blocks into a cohesive whole. I also figured that with the brick oven on top it was unlikely to move even without the mortar.

Step 4: Oven Slab

Picture of Oven Slab

Once the base has been completed, it is time to move on to the slab that will support the actual brick oven. I started with some 2 by 12 boards cut so that I could make a form around the top of the base. This form would allow me to pour an 8 inch, rebar reinforced, slab that would support the rest of the oven. I also used cement board as the base of the slab. Cement board is used to back tile installations where there is the likelihood that water will be involved.

Here are the layers for the slab.

  • 2x4's used to support the 3/4 inch plywood.
  • 3/4 inch plywood to support the cement board. The plywood needs to fit inside the walls of the base.
  • Cement board, these boards need to go all the way to the outside of the walls. Otherwise, you will be filling the walls of the base with concrete before filling the slab. Use duct tap to seal the gap between cement board.
  • Rebar is placed every 8 inches. Mine is supported, temporarily, by some extra bricks.
  • The form is placed around the outside of the walls. One tip, drive nails all the way through the form about 8 inches from the top. This will support the form and be fairly easy to remove once the slab has set.

Once your form is setup, find your brother-in-law (thanks Vic), and mix the 27 bags of concrete that will be used for the slab. Pour your slab and you are done for the day.

You might have noticed the missing rectangle in the top of the slab, this is for the "insulating concrete" that will be under the brick oven floor. "Insulating concrete" is a mixture of vermiculite and cement, 2 parts vermiculite to 1 part cement. We want this insulating layer so that we don't waste time heating the whole slab when using the oven.

Step 5: Brick Oven Floor

Picture of Brick Oven Floor

Now we get to the part where we actually start building the oven. For the building of the oven floor we use fire bricks laid on a thin layer of sand. As you can see, I have laid the brick in a herringbone pattern. Where the brick extend beyond the edge of the brick dome, I used a tile saw to trim them to shape. The bricks are not mortared to the slab so that, if need be, I can pull up and replace any brick that becomes damaged over the years.

One word of note, only use fire bricks when building the actual oven part of the brick oven. Other bricks are not made to handle the 850-900 degree heat and all of your hard work will not last for long.

Once you have placed the floor of the oven, it is time to move on to the walls.

Step 6: Oven Walls - First Layer

Picture of Oven Walls - First Layer

For the first layer of bricks, I choose to stand the bricks on end. You can choose to cut the bricks in half and then build up the layer, it is your choice. On the floor of the oven, I used a pencil and drew the placement of the bricks. I then dry fit the bricks. If you are wondering, the inside diameter of the oven is 36 inches. Once I was happy with the placement of all of the bricks, I mortared the bricks in place using firebrick mortar. The joints are around 1/4 inch, with the bricks almost touching on the inside of the oven.

Step 7: Oven Walls - Dome

Picture of Oven Walls - Dome

Once I started the second layer, the tile saw paid for itself. Each of the layers consists of half bricks that are angled inward at a slight angle. I initially used wedges to hold the angle of each brick but soon found that this was not necessary. When placing a brick, try not to line up seams between bricks. This will create a line of instability that will be prone to fracture. Think of the bricks as being similar legos, when you build a wall, you want to stagger the joints so that your wall is strong.

The opening of the oven is important in both size and shape. There is no opening in the top of the oven so the air used to fuel the fire and the exhaust from the fire use the same opening. The correct proportion for this opening is that the door needs to be 2/3rds the height of the dome height. So, if your oven height is 12 inches the door height should be 8 inches. Once the oven door size is determined, your can build your door. To get the arch for the door, I used a form that I built. Just outside the oven door, I have a chimney that will move the smoke from the fire up and away.

So for each of the layers of the oven, I cut the bricks in half, staggered the joints, and slowly moved toward the top of the oven. For the last couple of layers, I used a leftover board, some bricks and sand to create a form. This allowed me to place the last couple of layers without the bricks falling into the oven. I am sure that there are people that can do this portion without using the form, I am not that person. If I were to do it again, I would remove the form sooner and clean the sand from the top of the oven. No one sees it but I know that it is there.

Step 8: Oven Chimney

Picture of Oven Chimney

Here are some more shots of the chimney. Using fire brick and mortar for the lining. Not much else interesting to say.

Step 9: Insulating the Oven

Picture of Insulating the Oven

As you can see from the pictures, I have finished the dome of the oven and now need to insulate it. I had two options: insulating concrete or a rock wool blanket. One was cheap and the other was not, can you guess which one I chose? So I mixed cement and vermiculite as mentioned earlier in this Instructable and applied a 4 inch layer to the sides and a 6 inch layer to the top.

Side note: cement is used to create concrete (cement and aggregate). I used concrete for the foundation and oven slab. I used cement to make the insulating concrete.

The insulating concrete is kind of a pain to work with as it does not stick that well to itself. Once completed though, it is fairly sturdy. On top of the insulating concrete I applied a layer of Quikwall to water proof the oven.

Step 10: Finishing the Oven

Picture of Finishing the Oven

The facade for the oven was created using bricks that I pulled up from an old patio the previous owner of my house had built. These bricks do not have to be fire rated so just about anything will do. The better your brick laying skills, the better it will look. I wish I was better. Since the oven is complete, you can now start the curing fires. There is a progression of fires needed to cure the oven while not damaging it. I would suggest no more then one fire per day. Fornobravo.com has a full schedule that you can follow when curing your oven. My schedule was the following:

  1. Small fire with just a little bit of kindling. No medium or large logs. Let the oven cool before progressing to the next fire.
  2. Another small fire with one or two small pieces of wood.
  3. Medium size fire with 3-4 medium pieces of wood.
  4. Large fire as shown in the picture.
  5. Use as desired.

For my oven, I use a combination of birch and oak. Birch burns hot and fast. Oak sustains a fire while providing a fair amount of heat. It takes about 2.5 hours for the oven to heat pizza temperature, once I start the fire. I can tell that the oven is ready because all of the soot from the initial part of the fire has burned off the inside of the oven. Once the oven is at temp, I push the all of the coals to the edge of the oven. I then wait 10-15 minutes for the floor of the oven to cool slightly and start cooking pizzas. If I am cooking lots of pizzas, I add an additional log or two on top of the coals for some additional heat. If you are wondering, it takes about 1.5-2 minutes for a pizza to cook.

Step 11: Finishing the Oven - Again

Picture of Finishing the Oven - Again

So the oven was completed and we used it a lot for the first year. One thing that I noticed was that I kept getting cracks in the outside shell of the oven. This was not good as it let water into the oven. Water takes a lot of wood and time to heat up and burn off. After dealing with this for over a year, I decided to modify the oven. I build some walls and a roof using steel studs with concrete board sheathing the walls and plywood for the roof. I spent some time finishing it so that the new matched the old. I now have a water tight oven that is a joy to use.

Please let me know if you have any questions.

Time to build: 100-200 hours

Weight: about 20,000 pounds

Chiropractor visits: 5-10

Use: during the summer about twice per month

Coldest use: December, in the snow

Largest number of pizzas: 20, cub scout party

What can you cook: anything that you can do in an oven. If you don't need the oven at 900 degrees, heat it up and let it cool before starting to cook.

Comments

tonygoffe (author)2017-11-28

For the heat-proof mix ...perlite, cement.. is that 2 : 1 DRY MEASURE ??

I'm in /Jamaica, and have settled on a cast high-temp cast cement dome with perlite, cement, water glass (sodium silicate) mix.. Am building on the fire-bricked base of my 1st smoke house ..(live near a bauxite to aluminum refinery and had accumulated quite a few kiln bricks... Good post !11

Dan J Addlington-Lee (author)2017-11-21

Brilliant! I built myself a Multimedia (yeah stick with me!) Pergola this year, I plan to add my Oven this year so will be using a lot of the instructions here to implement into my oven. Great work, check out my Pergola, which I will upload the Instructable as soon as I have a moment lol!
My oven will go to the right of the Pergola, just past the Multimedia Cupboard (where our sound systems/video leads are housed and speakers/spare bits are stored, especially on Projector nights!)

Great job, I really like it. Check out Fornobravo.com as there are tons of examples to give you ideas. Everything from a brick base to a 2 in square steel support. Good luck.

Thanks I will, I actually needed reminding on this as I have not been well over the last three weeks! I will check it out now and plan my builds as soon as I am well enough...

M.J.J (author)2017-11-24

Beautiful! Thanks for showing all of the steps that are now hidden. In future designs,now that you've used this one extensively, would you think that having more of a shelf or counter on either side of the door to be helpful?As a landing place for small pizzas, or to warm plates, trays, etc? Maybe tile?

jamesdhatch (author)2017-11-21

Looks great. As the original author of the Pompeii Oven plans - yeah, I'm that Jim and the pics of the oven & kids in the plans are mine :-) I love seeing people building these. A couple of notes - the original design was a modified hybrid design that was intended to work well for both pizza (low thermal mass & short ceiling) and bread or other food (high thermal mass & tall ceiling). That's why the dome was shaped the way it was with the short bricks as the first row. With the tall bricks the roof tends to get too high for pizza unless you flatten it as you did and tilt the rising bricks more than designed. That leaves you with more mortar exposed to the fire - the original design keeps that to a minimum by aligning the edges of the fronts of the bricks. Keep an eye on that mortar as you use it. You may find the mortar spalling and need to repoint the bricks occasionally as you use it.

You switched the insulating vs thermal layer in the slab under the dome. Were you not interested in using it as a retained heat oven for bread/meat/etc? With the insulation layer under the oven deck it won't tend to retain enough heat for baking & roasting. But it does help with pizza because it heats up faster. If you want to use it for both pizza & other foods (using retained heat vs an ongoing fire), you'd want to switch the insulating and standard concrete by putting the thermal layer outside the base of the oven. That keeps you from having to heat the entire mass of the slab but allows enough to be retained so you can do a bake or two of bread or roasting using the retained heat from a fire you rake out before baking.

jbutterfield (author)jamesdhatch2017-11-21

I have used the oven for baking bread and cooking things other then pizza and find that the performance is just fine. That being said, I have not tried baking multiple loaves of bread or a large amount of meats based on retained heat. Maybe in the next house I own, I will change up the design. By the way, thanks for putting the designs on the web. It was a huge help when I designed my oven and I think the overall results were improved due to those plans.

jamesdhatch (author)jbutterfield2017-11-21

I got started on the venture after reading the Bread Bakers Apprentice but I wanted an oven that didn't take all day to heat up. Kiko Denzer's clay ovens were great but not if you live where there's no clay (I'm on sand myself). So I had to go it alone for awhile.

You can cook an amazing amount of stuff in there - it's pretty cool. One of the reasons it's the size it is was to let me have a door height tall enough to slide a turkey in. I had helped a friend build an Alan Scott loaf-shaped oven so he could do Thanksgiving dinner in it - and then the turkey didn't fit :-)

James at Fornobravo was my cohort in crime on this - he was wandering the countryside of Italy at the time and would peek inside people's backyard ovens to see how they were built. We'd compare notes & I'd design and build and then he'd check ovens to see if I was doing it right. It was a fun summer. He volunteered to host the plans (and a whole group of people sprung up around it to keep them modified and updated over time) because he just thinks everyone should have a backyard oven and if they can't buy his, he'll help make sure they can build their own.

I tried to make it materials you could get from your local big box home store but I would still get emails from people in Brazil or somewhere else far away and ask "we don't have a Home Depot, what is that?" Early days of the internet and user groups.

I still bump into people who have the plans and didn't know it was me. Then we get into detailed conversations about thermal mass and insulating concrete and everyone around us backs away and shakes their heads :-D

RyanW132 (author)jamesdhatch2017-11-23

I just wanted to comment that a lack of good clay soil is not really a problem if you want to build a clay oven. I built a Kiko Denzer style clay oven using fire clay purchased from Home Depot. That saved all of the work of digging, sifting out all of the rocks, etc... and made a very consistent building material. Fire clay is very inexpensive as well!

That being said, if I could find an inexpensive source of firebrick, I would love to do brick for my next oven!

jbutterfield (author)jamesdhatch2017-11-22

Jim-

Thanks for the comments! It is really nice to get non-judgemental advice from someone that has a ton of experience. Maybe next time mine will turn out better, we can always hope to improve.

jamesdhatch (author)jbutterfield2017-11-22

:-) Yours probably heats up a tad faster - the insulating layer under the brick eliminates a bunch of mass that you'd have to heat. These things should always be built for a use case - if you don't do overnight or next day cooks on retained heat then don't put mass under the bricks or worry about dome height as much. That's how this oven got started in the first place - Alan Scott's oven (he's an old school wood burning brick oven guru that kind of started the whole movement) is best for commercial operations and lots of bread - so much mass to heat but it retained it forever. Just takes 6-8 hours to heat up :-) Everyone's experience in building these helps everyone who follows.

The reason we named it the Pompeii oven is because it's remarkably similar in design to ones unearthed in Pompeii - built almost 2000 years ago! They're great if you have family or entertain. My kids grew up with pizza parties all the time. Good way to keep an eye on them when they're at your house and not out & about causing mischief ;-)

jbutterfield (author)jamesdhatch2017-11-22

I agree, best way to know who is at the party is to host the party.

t.rohner made it! (author)2017-11-22

Very nice design.

My clay oven had its tenth annyversary this year. (Also on instructables)

meanblackbike (author)2017-11-22

About the chiropractor - if you don't already get a weight lifting belt - the bigger the better. Use it tight and do not do unwise weight lifting - use ropes and any mechanical advantage you can think of - levers... (Archimedes).

For insulation seems a good idea those rock wool with aluminum foil for ovens like this one.

However yours is classic and lovely we all like it for that.

I hope you are not running with a hammer after this comment :) to make another one.

Thanks for the suggestion. The chiropractor was more because I was bending over and doing activities that are not part of my day job. I would have liked to use rock wool but the cost and not knowing how much would be needed kept me from spending the money. Maybe next time.

GregÓ35 made it! (author)2017-11-21

Very interesting. I just completed a very similar project here in Ireland.

If I ever build another oven, I'll put vermiculite under the floor, but in my defence, at least when I noticed the roof was getting too hot I put a vermiculite layer on top of it to keep the heat in.

It's not clear why the interior of the oven needs to be a hemisphere, but perhaps that's tradition. As a newcomer to this sort of thing, old wisdom would be welcome.

How do you operate the oven? Do you close off the chimney once the fire is fully developed?

jbutterfield (author)GregÓ352017-11-22

The chimney is outside the dome so I do not close it off. If I bake bread then I heat up the oven, take the remaining coals out, put the loaf in (when cool enough), and put a board in the doorway to the oven. Retains the heat for the baking process. You can also use a handheld sprayer to add a mist of water for a wet heat. I really like your oven.

Pa1963 (author)2017-11-21

A friend of mine built a similar oven out of concrete using chunks of concrete saved from a driveway demolition. Also, depending on where you live, you can buy ready mixed concrete that's loaded into a 1 0r 1 1/2 yard dump trailer, which you then tow with your own vehicle to your site. Costs a bit more per yard until you figure a less than load charge for a 10 yd mixer to deliver it, and the other charges involved. then I believe you are at parity with the big ready mix companies. Or rent a towable mixer for the job, then mix it yourself.

porgo0 (author)2017-11-21

Perfect
*push witch in it*

VICTORCAMP (author)2017-11-21

EXCELENTE

Tenire (author)2017-11-21

rock on, Jim!

chrisb1111 (author)2017-11-21

Very nice project indeed, congratulations! I have built several wood fired ovens myself and I would suggest that you put a layer of vermiculite cement of about 10 cm in between the oven slab and the brick oven floor. Otherwise the oven floor tends to cool off and dissipate a lot of energy to the oven slab. This is a disadvantage for instance when preparing pizze over a certain amount of time.

Suggested volume of vermiculite to volume of cement approximately 3 to 4:1, i.e roughly double the proportion of cement as compared to vermiculite cement for insulation of the dome.

Another hint: use chickenwire to stabilize the vermiculite cement for the dome insulation, makes the handling/sticking much easier.

My first oven was without this insulation and generally works fine. The next are with this type of additional bottom insulation, in my opinion a clear advantage.

Rickesss (author)chrisb11112017-11-21

Chrisb111,

Looking at his additional photos of the slab build, he did insulate with vermiculite/cement, using 2 parts vermiculite to 1 part cement, which was the same proportion he used with the dome covering.

2 1/2 hours to heat up the oven IS a long time, though. My buddies oven that he made was using "refractable concrete" (don't know how the efficiency compares to home brewed vermiculite/concrete) and it heats up to 800 or so in about an hour. I don't know what thickness he did the floor or dome.

I need to research the most efficient proportion of vermiculite to cement, to get the warm up time quicker.

Maybe your 4:1?

Outstanding build, jbutterfield!! 20,000lbs, wow!

RicklesssS in Oregon

jbutterfield (author)Rickesss2017-11-21

I think that insulation and oven wall thickness is a definite variable in the oven heating time. Thinner walls and more insulation would allow the oven to heat and cool faster. My walls are 4 inch thick brick, so there is a lot of mass that needs to be heated. It does stay hot for a long time though.

Kenluddite (author)2017-11-21

Beautiful work! My Italian family would be proud. One skill I have yet to tackle; Masonry. Ya got all the stats in there - but - Cost?

jbutterfield (author)Kenluddite2017-11-21

Cost was about $2000-$3000. Most of the materials are cheap. Fire bricks and refractory cement are not.

ajayt7 (author)2017-11-21

Gigantic job! You are more than a one man army! I am trying to imagine the colossal effort you must have put in. You surely are a man of solid determination. Congratulations

Beekeeper (author)2017-11-21

Excellent work. I made a similar oven http://www.setimanitoba.org/home/2017/10/4/making-a-wood-fired-outdoor-pizza-oven.html and wish I had used fire bricks for the dome. Otherwise my ideas might inspire a few people.

SusanH75 (author)2017-11-21

An ambitious undertaking. Bravo.

DIY Hacks and How Tos (author)2017-11-19

I have been thinking about making one of these. How do you monitor and regulate the temperature.

When a handful of flour thrown on the sole of the oven will become bron then black without burning, it's at about 250°C (or about 480°F) which is ideal for cooking bread.

I have three thermocouples in the oven. Top, side, and bottom. They are cool and I used them for the first three or four times I fired up the oven. Now I judge the heat based on how the inside of the dome looks.

deluges (author)2017-11-20

Very nice oven! But 20 pizzas? You gotta scale up man ;)

carlos66ba (author)2017-11-19

Amazing build! Hope you get good use for it.

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