Outdoor Pizza Oven

I have always wanted to build a pizza oven, and I finally did. I have no prior experience in making pizza ovens or working with cement, so there was a lot of learning during this process.

I started by making a rough draft of pizza ovens shapes and designs and decided on the semi barrel shape.

Supplies

OVEN:

Cement (A lot) : Regular for the base and counter, Portland for the oven mold

Perlite

Stainless Steel Needles

Firebricks

Refractory Mortar

Ceramic Insulating Fabric

Chicken Wire

Bricks

5" Stainless Steel Pipe

MOLD:

Hardboard

Plastic Light Cover (or other flexible material)

Lumber

Plastic Poly Sheet

Step 1: Foundation

I chose a flat location, and made a 5' x 4' mold for the base of the oven out of plywood. I lined the bottom of the mold with hardboard, so the cement I poured would not bond with the patio. I filled the mold with about 2.5" of cement.

Step 2: Bricks and Base

Once the base had dried I got some bricks and arranged them in a pattern I liked, then fixed them in place. Each brick is 4" tall, and there are 7 layers so the height is around 28".

Step 3: Counter

I made a mold 5'3" x 4' x 2" for the counter to allow for 1.5" of overhang on either side. I placed the mold in my garage (as it has a nice flat surface), and lined the ground with a poly plastic sheet. The mold was filled about halfway up, then a metal grid was added for additional support, before filling the mold. The mold was allowed to dry for a week before being added on top of the brick structure.

Step 4: Making the Molds

I made a mold for the fire chamber with plywood and hardboard. There were 4 parts to the mold: Entry, Main Chamber, Front and, Back.

Entry

The entry mold was made out of plywood and plastic light covers. It was 11.5" long x 24" wide (20" opening plus 2" on either side to account for wall width). The width of the walls was 2". The plastic used to create the walls of the entry was 38" x 11.5" to create a height of 12" (semi-circular shape). Although I used the plastic light covers to make the curved roof of the entry, this material was very brittle and I would suggest using something else. I made an aluminum foil "doughnut" covered in clear tape to create a space where the chimney would go.

Main Chamber

The main chamber mold was made out of plywood and hardboard. It was 33" long x 54" wide (50" plus 2" on either side to account for wall width). The width of the walls was 2". The hardboard piece used was 85" x 33" to create a barrel height of 27" (semi-circular shape).

Front

The front mold was made after the main chamber mold had dried and based off of it. It was made to sit inside the main chamber. It had an opening the same size as the opening on the entry mold. It was made of a plywood base, with a hardboard curve.

Back

The back mold was made after the main chamber mold had dried and based off of it. It was made to sit inside the main chamber. It was made of a plywood base, with a hardboard curve.

Step 5: Filling the Molds

All of the molds were filled with ~4:1 ratio of course perlite : portland cement and some stainless steel needles.

When packing the molds it is important the the cement mixture is tightly packed, and when filling the main chamber mold the mixture will need to be packed regularly as you go.

I let the molds dry for 2 weeks.

After dry I removed the cast pieces from the molds. After being removed from the molds all pieces were covered in a thin layer of portland cement.

Step 6: Firebrick Floor

I arranged the firebricks in a pattern I liked, and that I thought would allow a pizza peel to easily slide across. I marked the edge of the oven floor on the bricks, and used one brick to fill more than one edge gap where I could. The bricks were then cut and arranged in the pattern before being attached to the surface with an insulating cement.

Step 7: Oven Assembly

The 4 mold parts were assembled around the oven floor and attached together with refractory mortar.

Step 8: Insulating Fabric

A 2" ceramic insulating blanket was placed over the main chamber and back, then tightly wrapped in chicken wire.

Step 9: Chimney and Finishing Up

The Insulating fabric was then covered in portland cement. It took 3 layers to fully cover it, and then some finishing touches after that to make it nice and smooth. To attach the chimney, a stand was made to hold the chimney up in the entry. The chimney was placed onto the stand, and the gaps around the chimney were filled with refractory mortar to secure it in place.

Step 10: Test Fire

I started with a small curing fire lasting only around 10mins. Two days later I did a larger fire lasting around 30mins. I then did a fire lasting around 45mins.

Step 11: Pizza!

Char is flavor

Step 12: Failures

As stated at the start, I am a novice when it comes to working with cement, and as such there were several things that did not go too well along the way.

The original molds for the Front, Back and Main chamber ended up being redone.

The Main chamber mold piece cracked, due to inadequate concrete packing.

The Front mold piece did not fit, because the main chamber deformed a bit in the mold.

The back mold piece broke as it was knocked over.

Thanks for Reading!

Comments

[fablagrenouille]

Hi, nice Instructable but I'm planning to build my own bread and pizza oven and I'll use more
ecological and healthy
materials especially for
those in contact or above the food.



Cement
and refractory mortar contain bad chemical substances and refractory
bricks contain alumina (see
this article https://pubmed.ncbi.nlm.nih.gov/12214020/
on Aluminum exposure and Alzheimer's disease).




Normal
bricks are sufficient because they can admit temperature of 800°C
(1472°F) or
more
when the temperature of the surface of
the oven
will reach more or less 350°C (662℉) and the top of the chamber
500°C (932°F). Normal
bricks bricks
are
made
of clay, a
natural product. Mortar can be made of clay + sand + lime instead of
mortar
of cement
or
refractory mortar.
The thermal insulation above
the oven can
be made with natural products : a mix of 50% clay and 50% straw. In
the ancient times, cement didn’t exist but every where in the world
bread ovens were built with local and natural products.

[ld82625]

Hi, I love the oven. My question is how did you lift the concrete counter onto the structure, without breaking it? Alot of horse/man power I assume, but do you have advice on this, please? Thank you, Laura

[rower-11]

I got help from my brother and 3 friends. We lifted it onto a flat cart, rolled it beside the base then lifted it onto the base from the side. Once one side of the counter was on it was just a matter of getting it into the correct alignment. The slab was very strong, and won't break unless you drop it. I don't know how much it weighed but with 5 people lifting it was no problem.

[ld82625]

Thank you!

[Cueball21]

What are the stainless steel needles you speak of? What was their purpose? Where did you obtain them?

[rower-11]

The stainless steel needles were used to reinforce the concrete. I got them from an industrial supply retailer (OCL Industrial Materials), but you can find them on amazon I believe.

[Professor-Mousedude]

You should use a refractory cement designed to tolerate heat. Portland cement will degrade when you heat it, and will eventually start to crumble.
It should be called "castable refractory cement". Not the stuff in the plastic tub. You want the dry mix that comes in bags. Common brands are Shilp or Heatcast

[rower-11]

Thanks for the advice, If I make another I will use the refractory cement

[Microbe]

"metal grid" = reinforcing steel

[rower-11]

Thanks, I don't know the terminology

[dennisoersted]

Hey. Thanks for the great instructable - I'm looking forward to building my building my own pizza oven in the garden. I've got a question about step 2. How do you adhere the bricks together? Didn't see anything about it on the images or in your description.

[rower-11]

Oops, forgot that, I used Lepage premium PL. Thanks

[dennisoersted]

Thanks for that :)

[pdavis19]

While I appreciate the simple design, I wonder if this could be improved by having a couple of layers of brick underneath the cement slab and more bricks around the side and top.
Part of the idea of a brick oven is to use the bricks and cement to retain heat. If you have several layers of bricks underneath and up top, then you can throw some wood in, get the oven nice and hot, clear out the wood, and your oven will stay hot enough to cook for a few hours.
Contrarily, the more bricks you use, the longer it will take to bring the oven up to heat, so somewhere there's a happy medium and I guess it depends on your goal and how much you plan to use it.

[rower-11]

Thanks! That's sounds like a great way to improve the design

[Starkey0417]

I've wanted to build one of these! This looks awesome! I have to ask.....about how much did it cost?

[rower-11]

Thanks! It was around $650

[kbitznelson]

Thank you so much for your instructions in building an outdoor pizza oven. It's the thing that I have been (secretly-so my family doesn't moan) planning on for our patio. I especially appreciate your including the oops moments.

[rower-11]

Thanks you!

[yrralguthrie]

I know nothing about pizza ovens, but why is the chimney so close to the front? It looks like smoke would build up in the oven before it managed to exit up the chimney.