DIY Wood-Fired Pizza Oven

Can Also be Used to Bake Bread and Used as a Grill!

DIY Wood-Fired Pizza Oven

Reading Time: 8 minutes

The kids and I had a pizza from a wood-fired pizza oven at a restaurant. We liked it so much that we decided to build a pizza oven of our own. But not only for making pizzas, if done properly, it can bake bread, chicken, and for up to 72 hours after the fire goes out, it can be used as a grill.

I decided a 36” inside diameter oven made from firebrick would be the best for our wood-fired pizza oven. It would allow cooking for up to four pizzas at a time, and would be small enough to heat fast and keep clean. I made the cooking surface of the oven 42” high. I am 6’2” tall so that was a comfortable height for me.

I used a 22” wide door to allow room to slide a pizza and baking pans into the oven. The downside was, the bigger the opening, the faster the oven would lose heat. Using an insulated door took care of that problem.

I poured a 10’x10’ base due to the size of the oven and the need for the oven to be at a 45-degree angle. Next, the first two layers of concrete block were dry-stacked in place.

The rest of the blocks were dry-stacked in a crisscross pattern as that provides a lot of stability and strength to the structure. I left an opening of 24” wide and 36” deep to provide storage space for the wood I will use while cooking.

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The outside corners were then framed in and filled with rocks and steel before concrete was poured. Once both outside corners were done, the rest of the blocks were filled with steel and rocks.

The wood storage area was framed and poured at the same time when the concrete blocks were filled with concrete. (When you do this, have someone hitting the sides of the block with a rubber hammer. This will cause a vibration and minimize any voids in the concrete.) The next day, I built a frame for the gentle curve in front.

To support the base countertop, I added support using an angle grinder with a diamond blade and I cut grooves into the blocks to hold some old bed frames. I then placed concrete board over the wood storage area and added hog panels to act as rebar.

Once the oven is completed, there will be a second coat of concrete that will become the counter top.

I built a door frame that was 11 3/8” tall. While I was playing with the layout of the doorway, I was also looking at the location and size of the chimney. With this configuration, the chimney base was 4-1/2” wide and almost 11” long. (You can get an “oval to round” wood stove adapter that will let you use 6” stovepipe for the chimney.)

Because I don’t want to spend days heating up my oven, I used firebrick inside of it (2 1/2” thick, 4 1/2” wide and 9” long). This allows heating the oven in roughly an hour to 850 degrees F with no fear of the brick cracking and crumbling. I used roughly 170 bricks that were then cut down to fit as needed. I used my miter saw with a diamond blade and a stop to cut the bricks in half at a consistent size.

For the cooking floor of the oven, there were several options. Most people use full-sized firebricks for the floor. I went another route. I chose to use soapstone for several reasons.

• Soapstone can handle up to 3,000 degrees F without a problem.
• It’s easy to cut using woodworking tools with carbide bits.
• It will be smoother and easier to slide the pizzas in and out of the oven and there’s no worry about cracks in the firebrick floor.
• Soapstone heats up faster and will hold the heat longer than firebrick.

The only downside is that soapstone is not porous, which means any steam coming from the bottom of the pizza will not be able to escape as easily. This is handled by lifting the pizza every 30 seconds to let the pizza “breathe,” and since the pizza is in there only 90 seconds, that is not that hard to do.

From a company that makes countertops, I was able to get two pieces of soapstone “cutoffs,” 36”x 36” and 21”x 21”. I laid out the dimensions and made the circle cut on the big piece for the floor of the oven.

When building the oven, the cooking floor can be placed right on top of the concrete, but it will cause problems. Namely the concrete will suck away the heat from the oven so it will take a long time for the oven to get up to temperature. To stop this, I put insulation under the cooking surface and the concrete that supports it. This is to provide a thermal barrier and allows the oven to heat up in an hour. “Hard board” ceramic insulation is rated for 2,400 degrees F and the size I got from the local fireplace store was 2” thick x 24” wide x 36” long.

For my 36” oven (interior dimensions), three of the hard insulation boards needed to be cut. A small piece with an arched top will be for the door that I’ll be making.

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I wrapped aluminum foil around the insulation before the bricks were placed. This will stop the insulation from sucking moisture away from the concrete base and also from the mortar. The area where the door insulation was cut was filled in with extra pieces of foil.

Because firebrick stops heat better than mortar, the less mortar you use, the better the performance will be. I started at the door opening making sure to remain level at all times.

Firebrick will not stick to the mortar unless it is soaked in water for 30 seconds prior to using it. This is because it will suck away the water from the mortar before it has a chance to “bond” to the brick.

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The first row of bricks were placed upright. They went around the soapstone but were still sitting on the insulation. This is also when the small soapstone piece was shaped to match the concrete base.

After several layers of firebrick were placed, mortar was placed on the outside of the bricks to fill in any cracks and to help hold everything in place.

TIP: Once the bricks become almost vertical, they will slide easy. You can use hot water to soak the bricks in. This will speed up the bonding process but will not affect the structure in any other way.

Because the bricks were almost vertical and I didn’t trust my masonry skills, I used an exercise ball to hold the last of the bricks. Once the dome was built, I covered the oven with the leftover mortar. The oven sat for six days with the ball in place.

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The stovepipe was put on the oval to round adapter and the whole assembly was mortared into place and let dry overnight.

The insulation that goes over the oven is also made from ceramic, but instead of being a “hard board,” it’s more like a blanket. For every inch you have, it will reduce the outside temperature of the oven by 200 degrees. Since I will have the oven baking in the 850-degree F range, I used 4” of insulation. The insulation I used was 2” thick, 24” wide and 12’ long. I used three bundles. With this type of insulation, you will need to be careful on how you handle it. You do not want to breathe it in. I used a respirator, glasses, and gloves (with a long-sleeve shirt) and cut it into strips roughly 8” wide.

The first piece was cut into strips and put on vertically. After packing the vertical pieces as tightly as possible, the second layer went on horizontally.

Over the top of the insulation, chicken wire was installed to hold the insulation in place and to act as rebar for the stucco. Two coats of “brown” or “base” stucco were applied. I applied one coat one day and a second coat the following day. After letting the stucco dry for two days, I painted the oven with several layers of exterior grade paint to waterproof it.

The wood-fired pizza oven is almost ready to start cooking/baking, but not quite. If you light a fire to cook pizza, the water in the bricks and mortar will expand as it heats up and your oven will crack. It could even explode a few bricks. To stop that from happening, you have to cure the oven with a series low-heat fires that last at least five hours at a time. This will allow the water to escape and will also help the oven to get stronger as the water escapes. You do not have to do this on consecutive days.

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These are the temps/days that were used. Do not heat above the temperatures listed:

Day one: 140 degrees F

Day two: 215 degrees F

Day three: 300 degrees F

Day four: 400 degrees F

Day five: 525 degrees F

Note: You start with a very small fire, no bigger than your hand. Using an infrared thermometer, you watch the temp rise, only adding twigs when the fire is running out of wood. It takes a little time to warm the oven up. If it starts getting too hot, pull some of the burning material out. Slow and easy is the way to go.

When you cure the wood-fired pizza oven, use pure wood, nothing that is treated, glued, painted, etc.

Getting it up to 100 degrees F took only 15 minutes and the chimney drafted very well. The last day it didn’t take long to heat it up to 400 degrees F and when the outside of the oven was checked, it was at the temperature of the outside air.

I applied stucco over the concrete blocks to make them look nice. Next, it was time to pour the concrete countertop. After the frame was built, a countertop-sand mix was used to get a smooth surface. The concrete was colored black in the mixing process. Once the countertop was dry, I removed the forms and painted the base with an exterior-grade oil-based paint.

To cook a pizza in your wood-fired pizza oven, you want the interior of the oven to be no lower than 806 degrees F and it will take 60-90 seconds to cook. If the temperature is lower, the pizza will lose moisture and be very crisp. It will also take longer to cook (three minutes). You do not want the temperature any higher than 869 degrees F or the pizza will burn.

Once you have made a few pizzas and are comfortable with monitoring the temperature, try your hand at bread baking, using it to grill, etc. You will love the flavor your new oven gives to anything you cook up!

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Are you going to construct a wood-fired pizza oven of your own?

Originally published in Countryside July/August 2020 and regularly vetted for accuracy. 

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