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Can I build a mid-size refractory pizza oven for less than $500?

Yes, you definitely can.

First, let’s clearly define what we mean by a mid-size refractory pizza oven. This is an oven with roughly a 24-30″ round, interior firebrick cooking floor, with a cast masonry (refractory castable or non-refractory fireclay mortar) oven dome, reasonable insulation and a waterproof stucco exterior. The general idea is that this oven can be placed on either a metal stand or on an outdoor kitchen counter that the builder makes.

A mid-size refractory oven is able to make 1-2 pizzas at a time, it’s big enough to roast a chicken (but not a turkey), and it can hold various roasting pans and baking sheets. The 24-30″ size is very popular, because these ovens can heat up quickly, don’t take up too much space, don’t cost too much, and they can do a lot of cooking. This size is popular with people buying both steel and refractory ovens from Fontana, Alfa Forni, Forno Bravo, Pizza Party, Forno Venetzia and plenty of others. But those ovens typically cost at least $2,500, and often closer to $4,000-$5,000 when you buy one, rather than building one for about $400.

So if you have the time, and little bit of skill, you can do it for about $400. In general, you pour the oven base in concrete, assemble the cooking floor, cast the dome using a cardboard mold and castable material, insulate the oven, and then cover the whole thing with waterproof stucco. Let’s explore how you can do this in a little bit more detail.

First, you need to pour the base for your oven. For a 24″ interior dimension oven, you can either build a 32″ square or round base, 2 1/2″ thick with wire mesh reinforcement. Be sure the let the concrete cure before remove the side and bottom forms. Then, form and pour the 3.5″ vermiculite concrete floor insulating layer, and let it cure.

Your cooking floor will be 9×4.5×1.25″ firebrick splits that should cost less than $2.00 each. The bricks will be set on their flat/wide side, giving you a 1.25″ thick cooking floor, which is great. The cooking floor will last pretty much forever. Firebricks are readily available at your local brick/masonry supply store, and they should not require a special order.

Next, you will need to cast your oven dome using an inexpensive mold—either sand or cardboard. We recommend cardboard. And you will need to cast a roughly 1.5″ oven dome using a homemade mixture of locally sourced materials—fine mesh sand, Portland cement, hydrated lime and fireclay, plus a couple of fiber additives that improve the material’s strength that you order on the Internet.

The oven will be insulated with a combination of vermiculite or perlite insulating concrete, purchased either locally or online, in 4 cu ft sacks, and one roll of ceramic blanket insulation (50 sq ft, 24″x25’x1″). That will give your oven good, though not great, insulation, where it will cook and hold heat very well. If you’re lucky, and can find more ceramic insulation at a cost-effective price, including a second insulation blanket for the dome, and 2″ of CalSil boards for the floor, that would be great. Your oven would hold heat better. But if cost is your primary concern—the question is whether you can afford to do this in the first place, you don’t need to go to that step.

Your oven will be finished with chicken wire wrapped around the insulation blanket, covered with stucco purchased from Home Depot or Lowes, and painted.

The total weight of the oven should be around 450 lbs, where two strong guys can conceivably slide a couple of 2×4’s under the oven and lift it up. If you want to build the oven in-place, or you have access to mechanical equipment to move the oven when you’ve finished building it, you can make the oven much heavier with a 2″ thick dome and 2.5″ firebrick cooking floor for very little added cost, maybe $50. The heavier oven will take longer to heat up, though it won’t be terrible, maybe 30 minutes compared with about 20 minutes for the lighter, thinner oven, and it will hold heat longer for longer periods of pizza making, and better retained heat baking and roasting.

Here are the numbers. You will love what this oven can do, and the $400 price is an incredible deal.

Homebrew Castable Pizza Oven Material Costs
Lumber 2x4x96”236
Concrete mesh12020
Concrete 80 lb2714
Firebricks 9×4.5×1.25″ floor30260
Perlite 4 cu ft floor insulation15555
Blanket 1’x24”x25’ dome insulation1100100
Portland cement 95 lb12020
Hydrated lime 50 lb12525
Fireclay 50 lb12323
Sand 150 lb12020
Chimney 6×24”14545
Chicken wire 50×2’x2”11616
Sakrete bonding cement 50 lb33090