How To Build Your Own Cheap Outdoor Pizza Oven

Cob Oven How-To Instructions

The foundationcoboven-01foundation.jpg

With little more than some clay, sand, sawdust, brick, some recycled beer bottles and old cinder blocks, I had everything I needed to make my own oven. After familiarizing myself with Kiko’s cob oven design, I began building the foundation for my stove from the reclaimed cinder blocks and a few chunks of urbanite. A foundation raises the oven off of the ground and places it at a more convenient working height. (A hearth 40″ off the ground is a good average working height.)

A fire brick hearth with insulation

An insulating layer of beer bottles in a sawdust/clay mortar was assembled on top of the foundation in a ring of cob and beneath the firebrick hearth. The hearth, a simple arrangement of 17 recycled firebricks, would serve as the bottom of the cob oven, where breads and pizzas would bake directly. The hearth bricks were carefully laid on a thin bed of sand, so that they could be gently tapped to be firm and level.

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(Laying out the beer bottles, and later, filling in with sawdust/clay mortar)

Sizing the earth oven

I chose to construct a 22.5″ diameter oven, deciding that anything bigger would be beyond my current needs, and after using it, it’s definitely proven to be the perfect size. You can fit three medium-sized loaves of bread, or one or two small personal-sized pizzas in it at once. And at this small size, the entire mass can be heated to about 700 degrees in two hours of solid firing with good wood.

Making a brick arch doorway and cob dome

Before building the actual dome, I made an arched doorway with some reclaimed red brick, mortared with a sand/clay mix. (The doorway is a little narrow at 12 inches wide, but so far everything I’ve wanted to fit has slid right in. And it can’t make really big pizzas, but I’m liking the smaller sized pies.) The cob dome (nothing more than a mix of sand and clay at a 3:1 ratio) was carefully built up around a moist sand form covered with wet newspaper and up against the brick arch. The sand was piled out of the doorway after the dome had dried a bit.

coboven-08form.jpg coboven-10arch
(Tracing the brick arch to make a cardboard form, setting the bricks on the cardboard form)

coboven-12mortar coboven-15sandform
(Finishing touches on the clay/sand mortar between bricks, then making a smooth sand form)

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(Four inches of cob go up around the sand form, and later, the sand is dug out out the dome [interior view])

One more note about the door: the door is a critical 63% of the cob dome height, or 10″ high. (The dome is 16″ high, which is Kiko’s recommendation for cob ovens across the board.) This one measurement is the most critical because it allows the oven to actually draw. You see, the door is left open while the oven is firing, so that cool air is drawn in, and hot air and smoke can pass out the top half of the door. (Larger ovens frequently have a chimney, or you can make a simple firing door to help with draw, too.)

Cob dome insulation and some plaster

A several inch thick (between 2″-4″) layer of insulation (a mix of sawdust and clay slip) went over the whole dome. This layer helps to keep the heat longer, allowing for longer heat and longer bakes. Cob ovens built strictly for pizza don’t require such a layer, and more serious bread bakers may want to double up on insulation thickness, since it will allow for the baking of many loaves. Finally, a thick layer of earthen plaster covers and protects the whole thing.

coboven-20insulation coboven-22door
(2-4 inches of sawdust/clay insulation is built up, and next is the nearly finished product with earth plaster and a door)

That is pretty much the whole oven. Pretty simple, huh? Kiko’s book is a fantastic resource for how to build your own, and I highly recommend it. I didn’t work on the oven very inconsistently (due to weather, etc.), but I imagine it took less than a week of actual construction between April and I. (And much of the time is spent waiting for things to dry, too.)

Using Your New Outdoor Pizza Oven


There is nothing quite like wood-fired bread and pizza. Feeding the oven with wood, and watching the fire burn is an awesome experience. When the draw is just right, you can hear a low rumbling of the burning wood within the dome, which is rather powerful.

Other than being stupendous for baking tasty food, the oven is a great example of a simple technology that isn’t dependent on fossil fuels for its building or use. You need only simple natural and recycled materials for its construction, and wood to keep it baking. Getting away from cooking with propane is certainly in my realm of interests, and the oven has proven itself to be an important piece of that goal. This oven encompasses many of my loves: baking, cob, wood energy, and the DIY philosophy. Not only that, it cost less than $20. (The firebricks were the only significant cost at $1 each.)

If you have any interest in baking, especially baking really damn tasty bread and pizza, or baking without propane or other fossil fuels, check out Kiko Denzer’s Build Your Own Earth Oven for complete details and how you can get started! I cannot recommend it enough.

Please view all of the images of the cob oven building process here with more details!

p.p.s.: Want to get learn how to build your very own home with natural materials? Check out these exciting natural building workshop opportunities: a 2012 timber framing workshop, and straw bale  workshops at Dancing Rabbit Ecovillage in Missouri.


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  1. Built a cob oven in 1969 in Topanga Canyon…so long ago, lived in a tipi and things seemed so much easier. I’ve got a home made forge at my house here in N. Calif. and we’ve made all we can ourselves, but I have to say…there comes a point when your possesions start to possess you and it’s time to pull up stakes and just GO! I can remember being so proud that all i owned could fit in a backpack. Now I ook back, see that I’m doing okay as far as sticking to y core beliefs re; sustainablitlity, caring for the Mother and doing my part. growing food, herbs, making soaps, creams, lotions..all the stuff so many of us have done kinda behind the scenes. How did we pull up out front??

  2. I’ve always wanted to make a full authentic outdoor pizza oven – I think they add a heck of a lot of charm, and I can imagine that the pizzas you pull out just taste wonderful. Maybe I’ll get onto the DIY train one day and make one 🙂

  3. I have been longing to build an outdoor pizza oven off the kitchen for a while now, looked into the expensive oven cores that you custom build around to fit your style and hundreds of dollars and specialty masons needed and as the project of clearing a pile of timber that were felled two plus years ago to make room for the orchard, I realized we had way too much wood so I decided to do a little research on DIY outdoor pizza ovens. literally woke up one morning did a google search, found your site and started construction that morning, instead of off the kitchen I picked a spot in a shady corner of the garden. I used cinder blocks, big rocks, filled in with little rocks. I did not have any clay so I used some stone dust left from the drilling of a well years ago, some sub soil dug out of a dirt bacement, sand, to which I did add a little portland cement I had left from a tile making project cost so far $0.00 ˆdid the layer of bottles which I tried to use non returnable but total was over 2 cases worth. Bricks for the opening were saved from an old chimney and the fire brick came from a pizza oven my father had built 50+ years ago and had to take apart when his property go sold on the auction block under ’eminent domain’ ( never even knew he had built a pizza oven). The whole process took about a week and now is the hardest part, waiting for it to cure, on urging from family not to touch it or fire it for two weeks 14 days I have covered it with plastic and sprinkled it with water every other day . we are presently on day 9 stay tuned…..p.s. wish I could submit pics with this

  4. @Ziggy-How durable are these ovens to time and weather? I really want to do this up at my families’s summer house. I’m only up there a week in the summer, but my cousins are there longer. If there is no one to look after the oven during Spring/Fall/Winter, would it likely fall into disrepair? The area has been known to receive some heavy thunderstorms and wind. What are your thoughts?

    Sadly I live in an apartment with no outdoor area. Perhaps I’ll have to satisfy myself with solar ovens sitting on top of my car in the parking lot.

  5. Can i build a cob oven in december winter weather in virginia? It is in the 20’s at night and am wondering if things will dry properly or lead to cracking?

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